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  • 1.
    Lishchuk, Viktor
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. Metso Sweden AB, Sala, Sweden.
    Koch, Pierre-Henri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Butcher, Alan R.
    eological Survey of Finland/Geologian tutkimuskeskus, Espoo, Finland.
    Towards integrated geometallurgical approach: Critical review of current practices and future trends2020In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 145, article id 106072Article, review/survey (Refereed)
    Abstract [en]

    Geometallurgy has become an important tool for mitigating production risks and improving economic performance in the modern mining industry. Multiple definitions and visions of geometallurgy have been proposed during the last decades. Most of them define geometallurgy as a bridge between geology and mineral processing. Such a definition is rather confusing since process mineralogy claims to be such “bridge” too. Therefore, the main objective of the present paper is to provide a broad image of geometallurgy covering planning, executing and evaluation of geometallurgical programs. Such a vision of geometallurgy was developed within a research project PREP, which was aimed at “resource effective mineral processing”. PREP is a holistic geometallurgical approach independent of deposit type. The approach differentiates geometallurgical programs based on the complexity of the problem and the desirable outcome. Particular attention was paid to the planning of the geometallurgical programs, data management, and new tools development. The practical usage of the approach was tested with three case studies: iron-apatite ore, VMS, and Cu porphyry deposits. Some examples of applying geometallurgy for the iron-apatite ore are shown in this paper. The result, the guidelines on planning, executing and evaluating a geometallurgical program, are given in this paper.

  • 2.
    Chelgani, Saeed Chehreh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Parian, Mehdi
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Semsari, Parisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    A comparative study on the effects of dry and wet grinding on mineral flotation separation: a review2019In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 8, no 5, p. 5004-5011Article, review/survey (Refereed)
    Abstract [en]

    Water scarcity dictates to limit the use of water in ore processing plants particularly in arid regions. Since wet grinding is the most common method for particle size reduction and mineral liberation, there is a lack of understanding about the effects of dry grinding on downstream separation processes such as flotation. This manuscript compiles various effects of dry grinding on flotation and compares them with wet grinding. Dry grinding consumes higher energy and produces wider particle size distributions compared with wet grinding. It significantly decreases the rate of media consumption and liner wear; thus, the contamination of pulp for flotation separation is lower after dry grinding. Surface roughness, particle agglomeration, and surface oxidation are higher in dry grinding than wet grinding, which all these effects on the flotation process. Moreover, dry ground samples in the pulp phase correlate with higher Eh and dissolved oxygen concentration. Therefore, dry grinding can alter the floatability of minerals. This review thoroughly assesses various approaches for flotation separation of different minerals, which have been drily ground, and provides perspectives for further future investigations.

  • 3.
    Bahrami, Ataallah
    et al.
    Urmia University, Iran .
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Sharif, Jafar Abdollahi
    Urmia University, Iran .
    Kazemi, Fatemeh
    Urmia University, Iran .
    Abdollahi, Morteza
    Urmia University, Iran .
    Salahshur, Abbas
    Urmia University, Iran .
    Danesh, Abolfazl
    Urmia University, Iran .
    A geometallurgical study of flotation performance in supergene and hypogene zones of Sungun copper deposit2019In: Mineral Processing and Extractive Metallurgy, ISSN 2572-6641Article in journal (Refereed)
    Abstract [en]

    The feed of mineral processing plants, usually consist of different minerals from various geological zones, which show different behavior in separation processes. In this research, samples from supergene and hypogene zones were provided to investigate the flotation behavior of copper minerals. Flotation experiments were carried out in three phases of supergene sample, hypogene sample and mixed samples. Based on the results, the recovery rate of the mixed sample was 83.61%, which is 7.63% and 1.79% higher than the recovery of the samples of hypogene and supergene zones, respectively. The concentrate grade values obtained for blended, hypogene zone and supergene zone are 10.32%, 2.81% and 12.37%, respectively. The maximum values of flotation constant and infinite recovery are 0.956 (s−1) and 88.833% for the mixed sample. It was also concluded that the highest amount of k and infinitive recovery were related to supergene zone sulfide flotation which are 0.831 (s−1) and 84.33% respectively.

  • 4.
    Koch, Pierre-Henri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    A numerical study of the effects of microwave pre-treatment on value liberation from a zinc ore2019Conference paper (Refereed)
    Abstract [en]

    The extraction of mineral values from ore requires liberation followed by separation steps. Liberation is achieved by size reduction operations which are energy inefficient processes typically dominating the energy consumption in a mineral concentrator. As the grade of ore reserves declines, future viability of mineral operations will be determined by energy costs of comminution. The application of high power microwave energy to secondary crusher products has been suggested as a possible commercially viable thermal treatment method for reducing comminution energy and improving value mineral liberation. Recent studies have shown that microwave pre-treatment of coarse sphalerite ore particles (> 5mm) at specific microwave heating energies (1-3 kWh/t), induces microfractures and creates new crack surfaces. This suggests that subsequent crushing of these microwave treated particles could yield enhanced liberation. However, limited studies have been carried out investigating the mode of breakage and the extent of enhanced liberation in that case. The objective of this study is to develop numerical methods for quantifying the extent of enhanced liberation and mode of breakage in crushed microwave treated and untreated particles. Sphalerite ore particles representing small (-5+4.75) mm, medium (-16+9.5) mm, and large (-25+19) mm HPGR and cone crushed particles were microwave treated at specific energies between 1-3 kWh/t. Cracks in the ore particles before and after microwave treatment were analysed with QEMSCAN and numerical models of the measured particles (before and after microwave treatment) were developed in MATLAB. The propagation of random and nonrandom cracks was investigated by simulating comminution of the modelled treated and untreated particles. Results of this study demonstrate that the breakage mechanism and the liberation of valuable minerals from gangue in microwave treated and untreated particles is significantly different. This study contributes to the development of numerical tools to quantify crack propagation in heterogeneous ore particles.

  • 5.
    Guntoro, Pratama Istiadi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Tiu, Glacialle
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Application of machine learning techniques in mineral phase segmentation for X-ray microcomputed tomography (µCT) data2019In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 142, article id 105882Article in journal (Refereed)
    Abstract [en]

    X-ray microcomputed tomography (µCT) offers a non-destructive three-dimensional analysis of ores but its application in mineralogical analysis and mineral segmentation is relatively limited. In this study, the application of machine learning techniques for segmenting mineral phases in a µCT dataset is presented. Various techniques were implemented, including unsupervised classification as well as grayscale-based and feature-based supervised classification. A feature matching method was used to register the back-scattered electron (BSE) mineral map to its corresponding µCT slice, allowing automatic annotation of minerals in the µCT slice to create training data for the classifiers. Unsupervised classification produced satisfactory results in terms of segmenting between amphibole, plagioclase, and sulfide phases. However, the technique was not able to differentiate between sulfide phases in the case of chalcopyrite and pyrite. Using supervised classification, around 50–60% of the chalcopyrite and 97–99% of pyrite were correctly identified. Feature based classification was found to have a poorer sensitivity to chalcopyrite, but produced a better result in segmenting between the mineral grains, as it operates based on voxel regions instead of individual voxels. The mineralogical results from the 3D µCT data showed considerable difference compared to the BSE mineral map, indicating stereological error exhibited in the latter analysis. The main limitation of this approach lies in the dataset itself, in which there was a significant overlap in grayscale values between chalcopyrite and pyrite, therefore highly limiting the classifier accuracy.

  • 6.
    Koch, Pierre-Henri
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Automated drill core mineralogical characterization method for texture classification and modal mineralogy estimation for geometallurgy2019In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 136, p. 99-109Article in journal (Refereed)
    Abstract [en]

    In geometallurgy, a process model operating at the mineral liberation level needs quantitative textural information about the ore. The utilization of this information within process modeling and simulation will increase the quality of the predictions.

    In this study, descriptors derived from color images and machine learning algorithms are used to group drill core intervals into textural classes and estimate mineral maps by automatic pixel classification. Different descriptors and classifiers are compared, based on their accuracy and capacity to be automated. Integration of the classifier approach with mineral processing simulation is also demonstrated. The quantification of textural information for mineral processing simulation introduced new tools towards an integrated information flow from the drill cores to a geometallurgical model.

    The approach has been verified by comparing traditional geological texture classification against the one obtained from automatic methods. The tested drill cores are sampled from a porphyry copper deposit located in Northern Sweden.

  • 7.
    Lishchuk, Viktor
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Bringing predictability into a geometallurgical program: An iron ore case study2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The risks of starting, operating and closing mining projects have become higher than ever. In order to stay ahead of the competition, mining companies have to manage various risks: technical, environmental, legal, regulatory, political, cyber, financial and social. Some of these can be mitigated with the help of geometallurgy. Geometallurgy aims to link geological variability with responses in the beneficiation process by a wide usage of automated mineralogy, proxy metallurgical tests, and process simulation. However, traditional geometallurgy has neglected the non-technical aspects of mining. This has caused wide-spread discussion among researchers on the benefits of geometallurgy and its place in industry.

    In order to improve predictability in geometallurgy, such programs should cover planning, and the testing of hypotheses, and only then should there be an attempt to develop suitable technical tools. Such approach would ensure that those tools would be useful and are needed, not only from the technical point of view, but also from the users’ perspective. Therefore, this thesis introduces methodology on how to decrease uncertainty in the production planning and thus determine how much effort to put into decreasing uncertainty in geometallurgical programs.

    The predictability improvement of a geometallurgical program starts at the planning stage. The classification system developed here, through the survey (interviews) and literature review, indicates different ways to link geological information with metallurgical responses, and suggests areas where technical development is called for. The proposed developments can be tested before the start of the geometallurgical program with synthetic data. For the iron ore reference study (Malmberget), it was shown that implementation of geometallurgy is beneficial in terms of net present value (NPV) and internal rate of return (IRR), and building geometallurgical spatial model for the process properties (recovery and total concentrate tonnages), and that it requires fewer samples for making a reliable process prediction than concentrate quality. The new process and proxy for mineralogical characterisation models were developed as part of the geometallurgical program for the iron ore case study (Leveäniemi): an estimator of ore quality (ܺ௅்௎), a model for iron recovery in WLIMS, a model for iron-oxides liberation prediction. Additionally, it was found that DT may be applied only for studying marginal ores. The evaluation of different spatial process modelling methods showed that tree methods can be successfully employed in predicting non-additive variables (recoveries).

  • 8.
    Mulenshi, Jane
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Khavari, Pourya
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Characterization and feasible physical separation methods for Yxsjöberg historical tungsten ore tailings2019Conference paper (Other academic)
    Abstract [en]

    Relatively high minerals and metals content characterize historical tailings due to less efficient extraction methods and/or relatively low metal prices at the time. Repositories of such tailings pose environmental risks but could also become metals and minerals resources. An example of such tailings is the Yxsjöberg historical tungsten ore tailings in the Smaltjärnen tailings repository in Sweden.   

    The Smaltjärnen tailings repository was sampled by collecting drill core samples from different locations. The collected drill core samples were characterized physically (colour, texture, moisture content and particle size distribution) and chemically (elemental composition and distribution, and mineralogical composition). Feasible physical separation methods (magnetic and gravity separation) were pre-selected based on the tailings characteristics and the knowledge of processes from which the Yxsjöberg historical tailings were produced.

    In this paper, results from three drill cores each representing a different location on the tailings repository are presented. The tailings mass distribution was high in the coarser particle size fractions of +300 µm and +149 µm.  Tungsten (W) and Copper (Cu) were the metals of interest with one location having higher concentrations than the other two at 0.20 %WO3 and 0.14 %Cu. Sulphur (S) was recovered in the magnetic fractions of the LIMS and HIMS. Using the Knelson concentrator, W recovery was enhanced. These results are fundamental in the development of methods for separation of minerals and extraction of metals of interest from the historical tailings in order to leave behind an inert and environmentally safe residue.

  • 9.
    Bahrami, Ataallah
    et al.
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Hosseini, Mohammad Raouf
    Department of Mining Engineering, Isfahan University of Technology, Isfahan, Iran.
    Kazemi, Fatemeh
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Abdollahi, Morteza
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Danesh, Abolfazl
    Mineral Processing Plant, Sungun Mine, Tabriz, Iran.
    Combined Effect of Operating Parameters on Separation Efficiency and Kinetics of Copper Flotation2019In: Mining, metallurgy & exploration, ISSN 2524-3462, Vol. 36, no 2, p. 409-421Article in journal (Refereed)
    Abstract [en]

    This study aims to investigate the effects of operational variables on concentrate grade, recovery, separation efficiency, and kinetic parameters of the copper flotation process. For this purpose, the effects of the pulp solids content, collector and frother dosage, and preparation and concentrate collection time were studied using a Taguchi experimental design. The results of statistical analyses indicated that the concentrate collection time and pulp density were the most influential parameters on concentrate grade. Considering copper recovery, concentrate collection time, collector dosage, and pulp density were the most significant variables, in decreasing order of importance. Also, the separation efficiency was mostly influenced by the concentrate collection time. Furthermore, kinetic studies showed that the second-order rectangular distribution model perfectly matched the experimental flotation data. The highest kinetic constant of 0.0756 s−1 was obtained from the test, which was performed with 35% solids content and 40 and 20 g/t collector and frother, respectively. The highest predicted copper recovery of 99.57% was obtained from the test at 30% solids content, and the collector and frother dosages of 40 and 15 g/t, respectively.

  • 10.
    Koch, Pierre-Henri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Computational methods and strategies for geometallurgy2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    At the interface of geology and mineral processing, geometallurgy is a powerful tool for enhancingresource efficiency. A spatial model that represents the ore body in terms ofmineralogyand physical properties is combined with a process model that describes the concentrationprocess. The performance of a given ore in the process is computed in terms of gradeand recovery of the mineral of interest in the concentrate, but also the presence of potentialpenalty elements and energy costs. The inclusion of ore performance indicators in a blockmodel yields a geometallurgical model that considers the variations in an ore body.Progress has been made in recent years to list and study different processing options interms of data requirements and implementation costs. While providing useful data, littleadvance was made to guide decision-making and to handle uncertainty. The objective has,therefore, been to develop, choose and validate computational methods that suggest optimaldecisions in the scope of geometallurgical strategies for an iron ore and a porphyry copperdeposit.The selected approach is based on an analysis of structure and regularity fromthe ore blockdown to the mineral grains. By selecting the appropriate mathematical tool for each scale,the dimension of the data is reduced and the different scales are then taken into account inmaking decisions. Methods introduced for dimension reduction include machine learningmodels, statistical models and spectral descriptors. The decision models rely on stochasticmulti-armed bandits which are a form of reinforcement learning. The presentation of thedifferent models proceeds by zooming in from coarse scale to fine scale then taking a stepback and analyze the implications. Data that was collected during sampling campaigns andindustrial plant surveys is used to design and verify the proposedmodels.iWith regard to the dimension reduction problem, results showed the method’s ability toclassify mineral textures and identify mineral phases with more than 90 percent accuracy onthe selected data sets of optical images and incorporate different physical properties into ageometallurgical ore type classification. Decision results showed that strategies in the case ofa feed grade control or when different ore types were identified, resulted in a twofold increaseof a reward function which is either Boolean (the product fulfills quality requirements ornot), or continuous (an economic objective). The cumulative value of the reward functionmeasured the optimality of a processing strategy. Quantitative methods were introduced toevaluate ore classification as well as geometallurgical strategies.The achieved results suggest the introduction of these computationalmethods in the practiceof geometallurgy. The increased knowledge of different ore type performances and appropriatemodels lead to optimal decisions for improved resource efficiency along the ore valuechain. This is achieved by bothmaximizing profit and decreasing environmental impact, forexample by choosing processing routes that minimize energy consumption.

  • 11.
    Torres, Cynthia M.
    et al.
    Departamento de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte, Antofagasta, Chile. Centro Integrado de Pilotaje de Tecnologías Mineras, CIPTEMIN, Antofagasta 124000, Chile..
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Hernández, Pía C.
    Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta,Antofagasta, Chile.
    Justel, Francisca J.
    Departamento de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte, Antofagasta, Chile. Departamento de Ingeniería Química y Procesos de Minerales, Universidad de Antofagasta,Antofagasta, Chile..
    Aravena, Matías I.
    Departamento de Ingeniería Metalúrgica y Minas, Universidad Católica del Norte, Antofagasta, Chile.
    Herreros, Osvaldo O.
    Departamento de Ingeniería en Minas, Universidad de Antofagasta, Antofagasta, Chile.
    Cupric and Chloride Ions: Leaching of Chalcopyrite Concentrate with Low Chloride Concentration Media2019In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, no 10, article id 639Article in journal (Refereed)
    Abstract [en]

    In this paper, the effect of the cupric and chloride ions concentrations on copper dissolution from chalcopyrite concentrate was studied in acidified media. Variables included three different concentrations of Cu2+ (0.5, 1.5, and 2.5 g L−1), four different concentrations of Cl (0, 5, 7, and 10 g L−1), two different pH values of 1 and 2, and a constant temperature of 60 °C. Results indicated that addition of Cl to the system improves copper extractions, especially at higher concentrations of Cu2+. Initial copper concentrations in the leaching solution did not significantly affect the copper extraction when Cl was not present. Better copper extractions were obtained at pH 1 as compared with pH 2. As the Cu2+ and Cl concentrations were increased, higher values of redox potential were obtained. According to the formation constants of the chloro-complexes, the predominant species in the Cu2+/Cl system in the studied interval were CuCl+ and Cu2+. Using a model of copper speciation in the experimental range predicted for a single copper concentration with increasing Cl concentration, the Cu2+ concentration decreased significantly while the concentration of the chloro-complex species CuCl+ increased. In the leached residue, evidence of sulfur formation was found using SEM and corroborated by XRD analysis. When chloride is present in the medium, the amounts of copper and iron in the residue decrease, confirming a positive effect of chloride on the extraction of copper from concentrate for the studied conditions.

  • 12.
    Malm, Lisa
    et al.
    Boliden Mineral, Department of Process Technology, Boliden, Sweden.
    Sand, Anders
    Boliden Mineral, Department of Process Technology, Boliden, Sweden.
    Bolin, Nils-Johan
    Boliden Mineral, Department of Process Technology, Boliden, Sweden.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ymén, Ingvar
    RISE- Research Institutes of Sweden AB, Bioscience and Materials/Surface, Process and Formulation, Sweden.
    Dynamic vapor sorption measurement and identification of mineral species in industrial-scale flotation cell samples2019In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 356, p. 1016-1023Article in journal (Refereed)
    Abstract [en]

    In order to understand flotation performance in industrial-scale, it is of relevance to understand the surface properties and mineral species of materials contained in the various parts of the cell. In this work XRPD X-Ray Powder Diffraction) and DVS (Dynamic Vapor Sorption) were used to characterise the different minerals and the wettability of the sample collected at different depths in an industrial scale flotation cell.

    DVS is a novel technique for wettability measurement in mineral processing, of higher robustness and reproducibility compared to the Washburn technique.

    In the turbulent zone of the cell, the wettability properties are relatively similar, and decreases in the froth and concentrate. Differences in radial position were only found near the froth phase close to the shaft of the agitator.

    The main finding was that wettability information obtained by DVS could be correlated with mineral composition and particle size distribution.

  • 13.
    Bahrami, Ataallah
    et al.
    Department of Mining Engineering, Faculty of Engineering, Urmia University, Urmia, Iran.
    Kazemi, Fatemeh
    PhD Student of mineral processing, Faculty of Engineering, University of Kashan, Kashan, Iran.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Effect of different reagent regime on the kinetic model and recovery in gilsonite flotation2019In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 8, no 5, p. 4498-4509Article in journal (Refereed)
    Abstract [en]

    Gilsonite is a natural fossil resource, similar to an oil asphalt high in asphaltenes. To determine the effect of reagent regime on the kinetic order and rate of flotation for a gilsonite sample, experiments were carried out in both rougher and cleaner flotation process. Experiments were conducted using different combinations of reagent: Oil-MIBC; gasoline-pine oil; and one test without any collector and frother. According to results, kinetic in the test performed using the oil-MIBC and without any collector and frother were found to be first-order unlike the kinetic in the test conducted using the gasoline-pine oil. Five kinetic models were applied to the modeling of data from the flotation tests by using MATrix LABoratory software. The results show that all experiments are highly in compliance with all models. The kinetic constants (k) in rougher stage were calculated as 0.1548 (s-1), 0.2300 (s-1) and 0.2163 (s-1) for oil-MIBC, gasoline-pine oil, and test without any collector and frother, respectively. These amounts in the cleaner stage were 0.0450 (s-1), 0.1589 (s-1) and 0.0284 (s-1), respectively. The relationship between k, maximum combustible recovery (R) and particle size was also studied. The results showed that the R and k were obtained with a coarse particle size of (-250 + 106) μm in the rougher and (-850 + 500) μm in cleaner flotation processes.

  • 14.
    Hadavandi, E.
    et al.
    Department of Industrial Engineering, Birjand University of Technology, Birjand, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Estimation of coking indexes based on parental coal properties by variable importance measurement and boosted-support vector regression method2019In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 135, p. 306-311Article in journal (Refereed)
    Abstract [en]

    Coke as a fuel has a critical role for steel making industries. Since coke is a product of blended coals, it is essential to study relationships between parental coal components with quality of their coke products. Free swelling index (FSI) and maximum fluidity (MF) are standard coking indexes that widely used for blending coals and measuring quality of products. This study has been explored interdependencies between measured coal components by mutual information (MI) method and evaluated their importance in the prediction of coking indexes for a wide range of Illinois coal samples. MI results indicated that the set of moisture-organic sulfur and moisture-nitrogen-sulfate sulfur were the best variables for predictions of log(MF) and FSI, respectively. Adaptive Boosting method based on support vector regression (SVR), called Boosted-SVR, was used the selected variable sets for predictions of coking indexes. In testing stage of models, correlation of determination (R2) between actual and predicted values for the log(MF) and FSI were 0.89 and 0.90, respectively. These results indicated that Boosted-SVR model could quite satisfactory predict coking indexes. In general, outcomes of this investigation demonstrated an appropriate potential of coking quality prediction with limited numbers of input variables and suggested that a combination of MI with Boosted-SVR model as a new powerful tool which can be used for the computation of other complex fuel and processing problems based on measurement of conventional properties.

  • 15.
    Chelgani, Saeed Chehreh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Hadavandi, Esmaeil
    Department of Industrial Engineering, Birjand University of Technology, Birjand, Iran.
    Hower, James C.
    Center for Applied Energy Research, University of Kentucky, Lexington, KY, USA.
    Estimation of heavy and light rare earth elements of coal by intelligent methods2019In: Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, ISSN 1556-7036, E-ISSN 1556-7230Article in journal (Refereed)
    Abstract [en]

    Since last two decades, several investigations in various countries have been started to discover new rare earth element (REE) resources. It was reported that coal can be considered as a possible source of them. REE of coal occur in low concentrations, and their detection is a complicated process; therefore, their predictions based on conventional coal properties (proximate, ultimate and major elements (ME)) may have several advantages. However, few studies have been conducted in this area. This study examined relationships between coal properties and REE (HREE and LREE) for a wide range of coal samples (708 samples). Variable importance measure (VIM) by Mutual information (MI) as a new feature selection method was applied to consider the heterogeneous structure of coal and assess the individual relation between coal parameters and REE to select the compact subsets as input variables for modeling and improve the performance of prediction. VIM by MI showed that Si-Carbon, and Al-Hydrogen are the best subsets for the prediction of HREE and LREE concentrations, respectively. A boosted neural network (BNN) model as a new predictive tool was used for REE prediction. BNN can significantly reduce generalization of error. Results of BNN models showed that the HREE and LREE concentrations can satisfactory estimate (R 2 : 0.83 and 0.89, respectively). Results of this investigation were approved that MI-BNN can be used as a potential tool for prediction of other complex problems in energy and fuel areas.

  • 16.
    Lishchuk, Viktor
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Evaluation and comparison of different machine-learning methods to integrate sparse process data into a spatial model in geometallurgy2019In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 134, p. 156-165Article in journal (Refereed)
    Abstract [en]

    A spatial model for process properties allows for improvedproduction planning in mining by considering the process variability ofthe deposit. Hitherto, machine-learning modelling methods have beenunderutilised for spatial modelling in geometallurgy. The goal of thisproject is to find an efficient way to integrate process properties (ironrecovery and mass pull of the Davis tube, iron recovery and mass pull ofthe wet low intensity magnetic separation, liberation of iron oxides, andP_80) for an iron ore case study into a spatial model using machinelearningmethods. The modelling was done in two steps. First, the processproperties were deployed into a geological database by building nonspatialprocess models. Second, the process properties estimated in thegeological database were extracted together with only their coordinates(x, y, z) and iron grades and spatial process models were built.Modelling methods were evaluated and compared in terms of relativestandard deviation (RSD). The lower RSD for decision tree methodssuggests that those methods may be preferential when modelling non-linearprocess properties.

  • 17.
    Seyedhakimi, A.
    et al.
    Department of Research & Development, Faravari Pouya Zarcan Agh-Darreh Company, Tehran, Iran.
    Bastami, S.A
    Department of Research & Development, Faravari Pouya Zarcan Agh-Darreh Company, Tehran, Iran.
    Ghassa, S.
    School of Mining, College of Engineering, University of Tehran, Tehran, Iran.
    Razavi, H.
    Department of mineral processing engineering, Faculty of mining engineering, University of Amirkabir, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Exploring relationships between various activations of granular activated carbon on silver and gold adsorption: A kinetic and equilibrium study2019In: Separation science and technology (Print), ISSN 0149-6395, E-ISSN 1520-5754, Vol. 54, no 11, p. 1710-1721Article in journal (Refereed)
    Abstract [en]

    This investigation examined various kinetic and equilibrium models for gold (Au) and silver (Ag) adsorption from cyanide leach solution, onto surface of granular activated carbon (GAC) with 10, 35, 70 and 100% activities. Results indicated that the initial rate for Au and Ag adsorption is similar and increases by increasing the GAC activities. Outcomes showed that the adsorption for low activity GAC is proportional to the number of adsorption sites while the rate-limiting can be chemisorption for GAC with high activity. Thus, even low amount of contaminations on the fresh GAC can significantly decrease the capacity of precious metals adsorption.

  • 18.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Exploring relationships of gross calorific value and valuable elements with conventional coal properties for North Korean coals2019In: International Journal of Mining Science and Technology, ISSN 2095-2686Article in journal (Refereed)
    Abstract [en]

    Coal in North Korean (NKC) is one of the most important products; however, based on various strategic policies its detail properties remain opaque even for general researchers. Since there are some signs for opening of the North Korea economy, this investigation as a modest effort is going to explore principle relationships among some essential parameters of NKCs such as gross calorific value (GCV), valuable elements and conventional properties by different statistical methods. Correlations indicated that ultimate parameters (carbon, nitrogen, and hydrogen) are the best GCV predictors for NKCs in comparison with proximate parameters (ash, moisture and volatile matter). Multivariable regression demonstrated that predicted GCV based on ultimate properties has a quite accuracy when correlation of determination was 0.99. Descriptive statistics processes showed that on average, the contents of valuable elements such as Ga and V for NKCs are higher than the world coal ranges and they can be considered as byproducts of combustion of NKCs. Pearson correlations indicated that Y may have a mixed organic-inorganic affinity while Ga and V mainly occur in the inorganic part (mineral matter) of NKCs. High inter-correlations between Ga-V and Al showed that aluminosilicates can be considered as their main bring minerals.

  • 19.
    Mulenshi, Jane
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Khavari, Pourya
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Feasibility of gravity and magnetic separation for Yxsjöberg historical tungsten ore tailings2019Conference paper (Refereed)
    Abstract [en]

    Repositories of historical tailings (HT) pose environmental risks but could also become new resources for valuable metals. This is because relatively high minerals and metals content characterize them due to less efficient extraction methods and/or relatively low metal prices at the time. In this investigation, geometallurgical studies were conducted by collecting drill core samples (DCS) from the Smaltjärnen tailings repository in Yxsjöberg, Sweden. The collected DCS were from the main layers of the longest drill core, and were characterized physically (color, texture, moisture content and particle size distribution) and chemically (elemental composition and distribution, and mineralogical composition). The characterization of DCS indicated that the tailings mass distribution was high in the coarser particle size fraction of +149 μm. Tungsten (W) and Copper (Cu) were the metals of interest with highest concentrations being 0.22 %WO3 and 0.11 %Cu. Feasible physical separation methods selected were Knelson concentrator, LIMS and HIMS, based on the knowledge from literature, tailings characteristics, and assessment of processes from which the Yxsjöberg HT were produced. Using the Knelson concentrator, the recovery of scheelite, which is the main W mineral, was enhanced, with 75 wt.% tungsten recovered in the 34 wt.% of concentrate produced. In magnetic separation, sulphur (S) was mostly recovered in the ferromagnetic and paramagnetic fractions with only 1.0 wt.% in the non-magnetic fraction, meaning pyrrhotite, the main Fe-sulphide mineral in the HT responsible for AMD, was separated to the desired magnetic fractions of the LIMS and HIMS. These results are fundamental in the development of methods for separation of valuable minerals from these HT in order to produce an inert and environmentally safe residue.

  • 20.
    Nazari, S.
    et al.
    University of Tehran, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Shafaei, S.Z.
    University of Tehran, Tehran, Iran.
    Shahbazi, B.
    Tarbiat Modares University, Tehran, Iran.
    Matin, S.S.
    University of Technology Sydney, Sydney, Australia.
    Gharabaghi, A.
    University of Tehran, Tehran, Iran.
    Flotation of coarse particles by hydrodynamic cavitation generated in the presence of conventional reagents2019In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 220, p. 61-68Article in journal (Refereed)
    Abstract [en]

    Hydrodynamic cavitation (HC) (typically used to generate submicron bubbles) are frequently examined to improve froth flotation efficiency of ultrafine particles (−38 µm); however, the study of their effects on flotation parameters during the process of coarse particles (+100 µm) was not significantly explored. The main aim of this investigation is to discover the impacts of HC on effective flotation variables and flotation recovery of coarse particles (FRCP). Various surfactants (frothers: Methyl isobutyl carbinol (MIBC) and pine oil (PO), and dodecyl amine (DDA)) were used for the HC conditions. For comparison purposes, two series of flotation experiments in the absence and presence of HC were conducted by using coarse pure quartz particles (−425 + 106 µm). Variable importance measurements (VIMs) of random forest were applied to compare and assess impacts of flotation parameters (particle size, flotation conventional bubble (CB) size, impeller speed, and air flow rate) on FRCP in the absence and presence of HC. Outputs of VIMs indicated that the negative effect of particle size on FRCP was decreased and the capability of CB for floating coarse particles was improved in the presence of HC. Moreover, VIM results showed that in the presence of HC, the highest FRCP can be achieved when turbulent is lower. Generally, variations in the airflow rate had negligible impacts on FRCP. Flotation experiments suggested that HC in the presence of the collector can overcome the absence of frothers in a flotation system. These results can be used for enhancement of selective separation via froth flotation.

  • 21.
    Nwaila, Glen T.
    et al.
    School of Geosciences, University of the Witwatersrand, Wits, South Africa.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Becker, Megan
    Minerals to Metals Initiative, Department of Chemical Engineering, University of Cape Town, Rondebosch, South Africa.
    Frimmel, Hartwig E.
    Bavarian Georesources Centre (BGC), Institute of Geography and Geology, University of Würzburg, Würzburg, Germany. Department of Geological Sciences, University of Cape Town, Rondebosch, South Africa.
    Petersen, Jochen
    Minerals to Metals Initiative, Department of Chemical Engineering, University of Cape Town, Rondebosch, South Africa.
    Zhang, Steven
    School of Geosciences, University of the Witwatersrand, Wits, South Africa.
    Geometallurgical Approach for Implications of Ore Blending on Cyanide Leaching and Adsorption Behavior of Witwatersrand Gold Ores, South Africa2019In: Natural Resources Research, ISSN 1520-7439, E-ISSN 1573-8981Article in journal (Refereed)
    Abstract [en]

    Gold production in South Africa is projected to continue its decline in future, and prospects for discovery of new high-grade deposits are limited. Many of the mining companies have resorted to mining and processing low-grade and complex gold ores. Such ores are technically challenging to process, which results in low recovery rates, excessive reagent consumption and high operating costs when compared to free-milling gold ores. In the Witwatersrand mines, options of blending low-grade gold ores with high-grade ores exist. Although it is well known that most of the Witwatersrand gold ores are highly amenable to gold cyanidation, not much is known on the leachability of blended ores, especially the effects of mineralogical and metallurgical variability between different gold ores. In this study, we apply a geometallurgical approach to investigate mineralogical and metallurgical factors that influence the leaching of blended ores in a set of bottle shaker and reactor column tests. Three gold-bearing conglomerate units, so-called reefs, i.e., Carbon Leader Reef, Ventersdorp Contact Reef and the Black Reef, all in the Carletonville goldfield, were sampled. The ores were prepared using a terminator jaw crusher followed by vertical spindle pulverizer (20 kg aliquot) and high-pressure grinding rolls (80 kg aliquot). Mineralogical analysis was conducted using a range of complementary tools such as optical microscopy, QEMSCAN and micro–XCT. The results show that Witwatersrand gold ores are amenable to the process of ore blending. Some of the ores, however, contain impervious inert gangue and reactive ore minerals. Leach solution can only access gold locked in impervious gangue minerals through HPGR-induced pores and/or cracks. The optimum ore blending ratio of the bottle shaker experiments (p80 = − 75 μm) comprises 60% Carbon Leader Reef, 20% Ventersdorp Contact Reef and 20% Black Reef and yields 92% recovered Au over a leach period of 40 h. Blended ores with high carbonaceous material (> 1 wt% carbonaceous material, (Black Reef = 36–60%) yield lower recoveries of 60–69% Au). Ore leaching at the mixed-bed reactor column (− 75 μm and − 5.6/+ 4 mm) yields about 70% over a leach period of two weeks. We therefore suggest that the feasibility of ore blending is strongly controlled by the mineralogy of the constituent ores and that a mixed-bed reactor may be a viable alternative method for leaching of the low-grade Witwatersrand gold ores. Material from certain reefs, such as the Black Reef, has synergistic/antagonistic (nonadditive) blending effects. The overall implication of this study is that ore blending ratios, effects of comminution on mineral liberation, an association of gold with other minerals, and gold adsorption behavior will greatly inform future technology choices in the area of geometallurgy.

  • 22.
    Lishchuk, Viktor
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Koch, Pierre-Henri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Mattias, Gustafsson
    LKAB.
    Pålsson, Bertil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Geometallurgical characterisation of Leveäniemi iron ore: Unlocking the patterns2019In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 131, p. 325-335Article in journal (Refereed)
    Abstract [en]

    As part of a geometallurgical program for the Leveänimei iron ore mine, the Davis tube was used as proxy to classify ore types, predict iron recoveries in wet low-intensity magnetic separation (WLIMS), and to estimate liberation of mixed particles. The study was conducted by testing 13 iron ore samples with a Davis tube and a laboratory WLIMS. Ore feed was studied for modal mineralogy and liberation distribution with Automated Scanning Electron Microscopy. Data analyses to detect the patterns and data dependencies were done with multivariate statistics: principal component analysis, and projection to latent structures regression. Results show that a simple index (XLTU) based on mass pull (yield) in the Davis tube is capable of easy classification of magnetite ores. Using Davis tube mass pull and iron recovery, together with iron and Satmagan head grades may predict iron recovery in WLIMS. Also, the variability in Fe-oxides liberation pattern for magnetite semi-massive ores can be explained with the chemical composition of the Davis tube concentrate. It is concluded that the Davis tube test is better used only for marginal ores, since iron oxide minerals tend to be fully liberated in high-grade magnetite massive ores after grinding. The developed models may be used in populating a production block model.

  • 23.
    Mulenshi, Jane
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Geometallurgical study of historical tailings from the Yxsjöberg tungsten mine in Sweden: Characterization and reprocessing options2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tungsten (W) is listed among the European Union (EU) critical raw materials (CRMs) for its supply risk and economic importance. Primarily, tungsten is produced from scheelite and wolframite mineral ores with 0.08-1.5% tungsten trioxide (WO3) grade. However, as primary deposits for these resources are becoming less or lower in grade, alternative sources need to be explored. These alternative tungsten sources include scrap from end-of-life products, mine waste and rejects from the ore beneficiation processes (tailings). The latter alternative source is the focus within this thesis.

    Historical tailings repositories often pose environmental risks but may also become secondary sources of CRMs. This is because of relatively high minerals and metals content due to less efficient extraction methods and/or relatively low metal prices at the time of active mining. Therefore, reprocessing of such tailings is not only a supply risk-reducing measure but also an approach to remediation that contributes to the mining industry’s aim of moving towards a circular economy.

    The aim of this thesis has been to develop efficient methods for separating valuable minerals from the tailings in order to leave behind a stable and environmentally safe residue. Geometallurgical studies were conducted by collecting drill core samples from the Smaltjärnen tailings repository in Yxsjöberg, Sweden, for evaluating the potential of this repository for further processing. The tailings were originally produced from the ore that was mined by Yxsjö Mines while it was in operation from 1935 to 1963, with average ore grades of 0.3-0.4 wt.% WO3, 0.2 wt.% Cu and 5-6 wt.% fluorspar. The exploited minerals were scheelite for W, chalcopyrite for Cu and fluorspar. The tailings repository is estimated to have about 2.2 million tons of tailings covering an area of 26 hectares, with elemental concentrations of 1-2 wt.% S, 0.02-0.2 wt.% Cu, 0.02-0.3 wt.% W, 0.02-0.04 wt.% Sn and 0.02-0.03 wt.% Be.

    Sampling and characterization of the historical tailings were conducted based on geometallurgical units (i.e. a distinction between different layers and locations in the repository), followed by metallurgical test work. The tailings were characterized with regard to color and granulometry, particle size distribution, chemical composition, scheelite mineral occurrence, texture and mineral liberation, as well as mineralogical composition. Based on a comprehensive literature survey, tailings characteristics, and assessment of the earlier processes from which the Yxsjöberg tailings were produced, feasible separation methods were pre-selected involving dry low-intensity magnetic separation (LIMS) and high intensity magnetic separation (HIMS), enhanced gravity separation (EGS) using a Knelson concentrator, and batch froth flotation.

    The average WO3 and Cu concentration in these tailings based on the sampled locations was 0.15 % and 0.11 % respectively. Applying them to the estimated 2.2 million tons of tailings in this repository gives approximately 3300 tons of WO3 and 2512 tons of Cu. From the metallurgical test work, several feasible processing routes have been identified that need to be further assessed based on the economic and environmental criteria.

    The full text will be freely available from 2019-11-19 08:00
  • 24.
    Mulenshi, Jane
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Historical tailings as secondary sources of critical raw materials: Feasibility of reprocessing Yxsjöberg historical tungsten ore tailings2019In: In-use stocks and secondary supply of Critical Raw Materials (CRMs): 4th International Round Table on Materials Criticality (IRTC) Round Table, 2019Conference paper (Refereed)
    Abstract [en]

    The research shows the role historical tailings will play in the secondary supply of critical raw materials like tungsten. It also shows how the geometallurgical approach will play a significant role in assessing the feasibility of reprocessing such mine wastes, and developing efficient methods where residues that are inert and environmentally safe will be left behind. This holistic approach to reprocessing such historical mine wastes will contribute to the mining industry moving towards the circular economy. The Yxsjöberg case study is a good example of how the supply risk-reducing measure in material criticality would contribute to a circular economy in the mining industry.

  • 25.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Investigating the occurrences of valuable trace elements in African coals as potential byproducts of coal and coal combustion products2019In: Journal of African Earth Sciences, ISSN 1464-343X, Vol. 150, p. 131-135Article in journal (Refereed)
    Abstract [en]

    There is a growing attention in valuable trace elements (TEs) in coal and coal combustionproducts as they can potentially be future resources of valuable TEs. Therefore, understanding the mode of occurrences of valuable TEs in coal has several advantages for their economical and industrial extractions. Since there is limited information on the affinity of valuable TEs in the structure of African coals, this study explores correlations between conventional coal properties and concentration of vanadium, yttrium, gallium and lithium as valuable TEs for a wide range of African coal samples (139 samples) from South Africa, Botswana, Egypt, Tanzania, Nigeria and Zambia by statistical methods. Statistical assessments indicated that the concentrations of Y, V, Li and Ga for these countries are higher than their value in the world coal (on average). The outcomes of assessments showed that the Li, Ga and V are associated with the mineral matter fraction (inorganic affinity) of the coal where they have significant positive correlations with ash and Al (as a major element) and potentially clay minerals are their main bearing minerals. However, statistical explorations suggested that Y may have both the organic and inorganic occurrences in the African coal samples

  • 26.
    Sabzezari, Behrouz
    et al.
    Department of Mining Engineering, Tarbiat Modares University, Tehran, Iran.
    Javad Koleini, Seyed Mohammad
    Department of Mining Engineering, Tarbiat Modares University, Tehran, Iran.
    Ghassa, Sina
    School of Mining, College of Engineering, University of Tehran, Tehran, Iran.
    Shahbazi, Behzad
    Department of Mining Engineering, Tarbiat Modares University, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Microwave-Leaching of Copper Smelting Dust for Cu and Zn Extraction2019In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 12, no 11, article id 1822Article in journal (Refereed)
    Abstract [en]

    Industrial wastes may contain high concentrations of valuable metals. Extraction and recovery of these metals have several economic and environmental advantages. Various studies showed positive effects of microwaves as a pretreatment method before the leaching of minerals. However, there are empty rooms for exploring simultaneous microwave and leaching (microwave-leaching) of industrial waste material for the production of valuable metals. This investigation examined the microwave-leaching method to extract copper and zinc from a copper-smelter dust (CSD). The results of microwave-leaching mechanism were compared with conventional heating leaching based on kinetics modelling. The final Cu recovery in the conventional heating and microwave irradiation was 80.88% and 69.83%, respectively. Kinetic studies indicated that the leaching reactions follow diffusion across the product layer. Based on X-ray powder diffraction (XRD) analyses, during conventional experiments sulfate; components formed with high intensity as an ash layer which prevents reagent access to the solid surface and decreases the Cu dissolution. While the sulfate components did not detect in the microwave-leaching residuals which means that microwave irradiation helped to decrease the ash layer formation. Taking all mentioned results into consider it can be concluded that microwave-leaching can be considered as an efficient method for extraction of valuable metals from waste materials.

  • 27.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Prediction of specific gravity of Afghan coal based on conventional coal properties by stepwise regression and random forest2019In: Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, ISSN 1556-7036, E-ISSN 1556-7230Article in journal (Refereed)
    Abstract [en]

    Coal can be considered as the main fuel for electricity generation in Afghanistan. However, there is a quite limited data available about the overall quality, distribution, and character of coals in Afghanistan. Specific gravity (S.G) of coal as a key factor can be used for the estimation of potential tonnage production and be a fundamental parameter for the selection of coal washery process method. However, there is no investigation which comprehensively explores relationships between S.G and coal properties. In this investigation, the potential of S.G prediction based on conventional properties for Afghan coal samples was explored by stepwise regression and random forest. Pearson correlation (r) and variable importance measurement (VIM) of random forest (RF) were applied to select the most effective variables among conventional parameters for the S.G prediction. Results of VIM indicated that ash and carbon content of coal samples had the highest importance for the S.G prediction. Stepwise regression and RF models were developed based on these two coal variables. Testing the generated models indicated that S.G of Afghan coals can quite accurately predict by these models (R2 > 0.90). Modeling outcomes showed that the highest S.G (S.G > 2) for Afghan coal occurred when ash was higher than 40% and carbon was lower than 30%.

  • 28.
    Jonsén, Pär
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Hammarberg, Samuel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Pålsson, Bertil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lindkvist, Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Preliminary validation of a new way to model physical interactions between pulp, charge and mill structure in tumbling mills2019In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 130, p. 76-84Article in journal (Refereed)
    Abstract [en]

    Modelling of wet grinding in tumbling mills is an interesting challenge. A key factor is that the pulp fluid and its simultaneous interactions with both the charge and the mill structure have to be handled in a computationally efficient way. In this work, the pulp fluid is modelled with a Lagrange based method based on the particle finite element method (PFEM) that gives the opportunity to model free surface flow. This method gives robustness and stability to the fluid model and is efficient as it gives possibility to use larger time steps. The PFEM solver can be coupled to other solvers as in this case both the finite element method (FEM) solver for the mill structure and the DEM solver for the ball charge. The combined PFEM-DEM-FEM model presented here can predict charge motion and responses from the mill structure, as well as the pulp liquid flow and pressure. All cases presented here are numerically modelled and validated against experimentally measured driving torque signatures from an instrumented small-scale batch ball mill equipped with a torque meter and charge movements captured from high-speed video. Numerical results are in good agreement with experimental torque measurements and the PFEM solver also improves on efficiency and robustness for solving charge movements in wet tumbling mill systems.

  • 29.
    Larsson, Simon
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Pålsson, Bertil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Parian, Mehdi
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Jonsén, Pär
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Preliminary validation of a stirred media mill model2019Conference paper (Refereed)
    Abstract [en]

    Wet fine grinding is an important process in the minerals industry. Modelling of wet grinding in stirred media mills is challenging since it requires the simultaneous modelling of grinding media consisting of a huge number of small grinding bodies, moving internal stirrer, and the pulp fluid. All of them in interaction with each other. In the present study, wet grinding in a stirred media mill is studied using coupled incompressible computational fluid dynamics (ICFD) and discrete element method (DEM) and finite element method (FEM) simulations. The DEM is used to model the grinding media, and the pulp fluid flow is modelled using the ICFD. Moreover, the FEM is used to model the structure of the mill body and is in combination with DEM used to estimate the wear rate in the system. The present implementation of the coupled ICFD-DEM-FEM preserves the robustness and efficiency of both methods, and it gives the possibility to use large time steps for the fluid with very low computation times.

  • 30.
    Bahrami, Ataallah
    et al.
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Mirmohammadi, Mirsaleh
    School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Kazemi, Fatemeh
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Abdollahi, Morteza
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Danesh, Abolfazl
    Complex of Copper Processing-Sungun, East Azerbaijan Province, Tabriz, Iran.
    Process mineralogy as a key factor affecting the flotation kinetics of copper sulfide minerals2019In: International Journal of Minerals, Metallurgy and Materials, ISSN 1674-4799, E-ISSN 1869-103X, Vol. 26, no 4, p. 430-439Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to apply process mineralogy as a practical tool for further understanding and predicting the flotation kinetics of the copper sulfide minerals. The minerals’ composition and association, grain distribution, and liberation within the ore samples were analyzed in the feed, concentrate, and the tailings of the flotation processes with two pulp densities of 25wt% and 30wt%. The major copper-bearing minerals identified by microscopic analysis of the concentrate samples included chalcopyrite (56.2wt%), chalcocite (29.1wt%), covellite (6.4wt%), and bornite (4.7wt%). Pyrite was the main sulfide gangue mineral (3.6wt%) in the concentrates. A 95% degree of liberation with d80 > 80 µm was obtained for chalcopyrite as the main copper mineral in the ore sample. The recovery rate and the grade in the concentrates were enhanced with increasing chalcopyrite particle size. Chalcopyrite particles with a d80 of approximately 100 µm were recovered at the early stages of the flotation process. The kinetic studies showed that the kinetic second-order rectangular distribution model perfectly fit the flotation test data. Characterization of the kinetic parameters indicated that the optimum granulation distribution range for achieving a maximum flotation rate for chalcopyrite particles was between the sizes 50 and 55 µm.

  • 31.
    Malm, Lisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering. New Boliden AB.
    Sampling from large flotation cells: An invastigation of spatial distribution2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The general trend in flotation technology today is towards larger flotation cells, which enables a higher throughput. However, adverse effects such as segregation and reduced froth transport efficiency have also been observed in larger cells. To better understand these problems it is of relevance to understand how the minerals of interest are moving and distributed inside flotation cells.

    A sampling investigation of industrial scale tank cells has been carried out. The samples have been analyzed by their physical properties, such as grade, solid concentration, particle size distribution and mineral composition. A novel method of measuring the wettability has been validated against traditional techniques for characterizing the surface properties of mineral samples. Different techniques and devices for sampling has also been evaluated.

    The results showed segregation inside the cells, with the quiescent zone having lower particle size (P80) and lower weight % solid. The grade profile in the vertical direction was relatively constant even though the P80 and weight % solid decreased in the quiescent zone.

    The smaller particles in the quiescent zone contained higher fraction of soft clay particles, which also correlated with a higher degree of hydrophilicity.

  • 32.
    Tohry, Arash
    et al.
    Yazd University, Yazd, Iran.
    Dehghan, R.
    Yazd University, Yazd, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rahmani, O.
    Chadormalu Mining and Industrial Company, Yazd, Iran.
    Selective Separation of Hematite by a Synthesized Depressant in Various Scales of Anionic Reverse Flotation2019In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, no 2, article id 124Article in journal (Refereed)
    Abstract [en]

    Demand for high-quality iron concentrate is significantly increasing around the world. Thus, the development of the techniques for a selective separation and rejection of typical associated minerals in the iron oxide ores, such as phosphorous minerals (mainly apatite group), is a high priority. Reverse anionic flotation by using sodium silicate (SS) as an iron oxide depressant is one of the techniques for iron ore processing. This investigation is going to present a synthesized reagent “sodium co-silicate (SCS)” for hematite depression through a reverse anionic flotation. The main hypothesis is the selective depression of hematite and, simultaneously, modification of the pulp pH by SCS. Various flotation experiments, including micro-flotation, and batch flotation of laboratory and industrial scales, were conducted in order to compare the depression selectivity of SS versus SCS. Outcomes of flotation tests at the different flotation scales demonstrated that hematite depression by SCS is around 3.3% higher than by SS. Based on flotation experiment outcomes, it was concluded that SCS can modify the pH of the process at ~9.5, and the plant reagents (including NaOH, Na2CO3, and SS gel) can be replaced by just SCS, which can also lead to a higher efficiency in the plant. 

  • 33.
    Jafari, Mohammad
    et al.
    School of Mining, College of Engineering, University of Tehran, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Shafaie, S.Z.
    School of Mining, College of Engineering, University of Tehran, Tehran, Iran.
    Abdollahi, H.
    School of Mining, College of Engineering, University of Tehran, Tehran , Iran.
    Hadavandi, E.
    Department of Industrial Engineering, Birjand University of Technology, Birjand, Iran.
    Study effects of conventional flotation reagents on bioleaching of zinc sulfide2019In: Journal of Industrial and Engineering Chemistry, ISSN 1226-086X, E-ISSN 1876-794X, Vol. 78, p. 364-371Article in journal (Refereed)
    Abstract [en]

    Although flotation and bio-extraction of metals from its products are extensively investigated, there are few studied which evaluated the effects of reagents on bioleaching process. Both structure and concentration of flotation reagents are effective factors on microorganism activities. In this study, Kendall’s tau (τ) as a statistical method was used to statistically access the effect of typical sulfide flotation surfactants (collectors: potassium amyl-xanthate, potassium isobutyl-xanthate, sodium ethyl-xanthate, potassium isopropyl-xanthate, and Dithiophosphate), and frothers: pine oil and methyl isobutyl carbinol) on the bioleaching of Zn sulfides in a mixed culture (Leptospirillum ferrooxidans, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans). To consider both structure and concentration of these reagents, their molarities were used for the statistical evaluations. The Kendall assessments indicated that by increasing in the molarity of reagents, the pH value (the most effective factors of bioleaching) was increased (τ: 0.56) while the ORP value (τ: -0.54), Fe ratio (τ: -0.51) and numbers of oxidizing bacteria (τ: -0.38) in the solution were decreased. Therefore, as a result of these multi-interactions, by increasing the molarity of reagents, Zn recovery was decreased (τ: -0.45). These results potentially can be used for selection of flotation reagents when bioleaching would be the metallurgical metal extraction method.

  • 34.
    Bahrami, Ataallah
    et al.
    Department of Mining Engineering, Urmia University, Urmia, Iran.
    Kazemi, Fatemeh
    University of Kashan, Kashan, Iran.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    The Order of Kinetic Models, Rate Constant Distribution, and Maximum Combustible Recovery in Gilsonite Flotation2019In: Mining, Metallurgy & Exploration, ISSN 2524-3462Article in journal (Refereed)
    Abstract [en]

    Kinetic models are the most important tool for predicting and evaluating the performance of flotation circuits. Gilsonite is a natural fossil resource similar to an oil asphalt, high in asphaltenes. Here, in order to determine the kinetic order and flotation rate of a gilsonite sample, flotation experiments were carried out in both rougher and cleaner stages. Experiments were conducted using the combinations of oil–MIBC and gas oil–pine oil, with one test without collector and frother. Five kinetic models were applied to the data obtained from the flotation tests using MATLAB software. Statistical analysis showed that the results of the experiment with oil–MIBC were highly in compliance with all models. Kinetic constants (k) were calculated as 0.1548 (s−1) and 0.0450 (s−1) for rougher and cleaner stages, respectively. Rougher and cleaner tests without collector and frother also matched all models well (R2 > 0.98), with kvalues of 0.2163 (s−1) and 0.284 (s−1), respectively. The relationship between flotation rate constant, maximum combustible recovery, and particle size showed that the maximum flotation combustible recovery and flotation rate were obtained in the size range of −250 + 106 μm in the rougher and cleaner stages. The combustible recovery and flotation rate were higher in the rougher flotation process than in the cleaner stage.

  • 35.
    Guntoro, Pratama Istiadi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Use of X-ray Micro-computed Tomography (µCT) for 3-D Ore Characterization: A Turning Point in Process Mineralogy2019Conference paper (Refereed)
    Abstract [en]

    In recent years, automated mineralogy has become an essential enabling technology in the field of process mineralogy, allowing better understanding between mineralogy and the beneficiation process. Recent developments in X-ray micro-computed tomography (μCT) as a non-destructive technique have indicated great potential to become the next automated mineralogy technique. μCT’s main advantage lies in its ability to allow 3-D monitoring of internal structure of the ore at resolutions down to a few hundred nanometers, thereby eliminating the stereological error encountered in conventional 2-D analysis. Driven by the technological and computational progress, the technique is continuously developing as an analysis tool in ore characterization and subsequently it foreseen thatμCT will become an indispensable technique in the field of process mineralogy. Although several software tools have been developed for processing μCT dataset, but the main challenge in μCT data analysis remains in the mineralogical analysis, where μCT data often lacks contrast between mineral phases, making segmentation difficult. In this paper, an overview of some current applications of μCT in ore characterization is reviewed, alongside with it potential implications to process mineralogy. It also describes the current limitations of its application and concludes with outlook on the future development of 3-D ore characterization.

  • 36.
    Guntoro, Pratama Istiadi
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    X-ray microcomputed tomography (µCT) as a potential tool in Geometallurgy2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In recent years, automated mineralogy has become an essential tool in geometallurgy. Automated mineralogical tools allow the acquisition of mineralogical and liberation data of ore particles in a sample. These particle data can then be used further for particle-based mineral processing simulation in the context of geometallurgy. However, most automated mineralogical tools currently in application are based on two-dimensional (2D) microscopy analysis, which are subject to stereological error when analyzing three-dimensional(3D) object such as ore particles. Recent advancements in X-ray microcomputed tomography (µCT) have indicated great potential of such system to be the next automated mineralogical tool. µCT's main advantage lies on its ability in monitoring 3D internal structure of the ore at resolutions down to few microns, eliminating stereological error obtained from 2D analysis. Aided with the continuous developments of computing capability of 3D data, it is only the question of time that µCT system becomes an interesting alternative in automated mineralogy system.

    This study aims to evaluate the potential of implementing µCT as an automated mineralogical tool in the context of geometallurgy. First, a brief introduction about the role of automated mineralogy in geometallurgy is presented. Then, the development of µCT system to become an automated mineralogical tool in the context of geometallurgy andprocess mineralogy is discussed (Paper 1). The discussion also reviews the available data analysis methods in extracting ore properties (size, mineralogy, texture) from the 3D µCT image (Paper 2). Based on the review, it was found that the main challenge inperforming µCT analysis of ore samples is the difficulties associated to the segmentation of the mineral phases in the dataset. This challenge is adressed through the implementation of machine learning techniques using Scanning Electron Microscope (SEM) data as a reference to differentiate the mineral phases in the µCT dataset (Paper 3).

  • 37.
    Guntoro, Pratama Istiadi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Koch, Pierre-Henri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    X-ray Microcomputed Tomography (µCT) for Mineral Characterization: A Review of Data Analysis Methods2019In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, no 3, article id 183Article in journal (Refereed)
    Abstract [en]

    The main advantage of X-ray microcomputed tomography (µCT) as a non-destructive imaging tool lies in its ability to analyze the three-dimensional (3D) interior of a sample, therefore eliminating the stereological error exhibited in conventional two-dimensional (2D) image analysis. Coupled with the correct data analysis methods, µCT allows extraction of textural and mineralogical information from ore samples. This study provides a comprehensive overview on the available and potentially useful data analysis methods for processing 3D datasets acquired with laboratory µCT systems. Our study indicates that there is a rapid development of new techniques and algorithms capable of processing µCT datasets, but application of such techniques is often sample-specific. Several methods that have been successfully implemented for other similar materials (soils, aggregates, rocks) were also found to have the potential to be applied in mineral characterization. The main challenge in establishing a µCT system as a mineral characterization tool lies in the computational expenses of processing the large 3D dataset. Additionally, since most of the µCT dataset is based on the attenuation of the minerals, the presence of minerals with similar attenuations limits the capability of µCT in mineral segmentation. Further development on the data processing workflow is needed to accelerate the breakthrough of µCT as an analytical tool in mineral characterization.

  • 38.
    Malm, Lisa
    et al.
    Boliden Mineral, Department of Process Technology.
    Kindstedt Danielsson, Ann-Sofi
    RISE – Research Institutes of Sweden AB, Surface, Process and Pharmaceutical Development.
    Sand, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ymén, Ingvar
    RISE – Research Institutes of Sweden AB, Surface, Process and Pharmaceutical Development.
    Application of Dynamic Vapor Sorption for evaluation of hydrophobicity in industrial-scale froth flotation2018In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 127, p. 305-311Article in journal (Refereed)
    Abstract [en]

    The particle surface properties are essential for understanding froth flotation, particularly for the evaluation of various chemical or reagent effects.

    Dynamic Vapor Sorption (DVS) is used in the pharmaceutical industry for the evaluation of surface properties and has to the knowledge of the authors not been used for applications in mineral processing. This paper describes an evaluation of industrial ore samples using DVS.

    Four samples (feed, CuPb concentrate, Cu concentrate and Pb concentrate) from each of the Cu – Pb flotation processes in the Boliden and Garpenberg concentrators, Sweden, were analyzed by DVS in order to investigate if this technique could be used to estimate differences in their hydrophilicity. The DVS measures the water uptake as a function of the relative humidity (%RH) at constant temperature.

    For both series of four samples, it was found that the DVS-data are in precise agreement with the flotation theory on hydrophobicity (indicated by differences in water uptake). The feed material, without any collectors, adsorbed more water compared to the CuPb bulk concentrate, which in turn adsorbed more water than the Cu concentrate. The lead concentrate on the other hand, which had been depressed by dichromate and should be more hydrophilic, showed a higher adsorbance of water than that of the CuPb concentrate.

    The repeated measurements of three sub samples from one of the ore samples gave a mean value and an estimated standard deviation of 0.13 ± 0.01%. This shows that the method gives highly reproducible results and that the differences between the samples had high significance. This also shows that the DVS method can serve as a useful complement to traditionally used contact angle or capillary absorption-based measurement methods, especially when screening for new flotation reagents on industrial ore samples.

  • 39.
    Leiva, Claudio A.
    et al.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Arcos, Katheryn V.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Poblete, Diego A.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Serey, Eduardo A.
    Department of Chemical Engineering, Universidad Católica del Norte, Chile.
    Torres, Cynthia M.
    Department of Metallurgical and Mining Engineering, Universidad Católica del Norte, Chile.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Design and Evaluation of an Expert System in a Crushing Plant2018In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, no 10, article id 469Article in journal (Refereed)
    Abstract [en]

    This document presents a proposal for designing an expert system in the Gabriela Mistral Division’s crushing plant belonging to Codelco (Chile) with the objective of maximizing stacked tonnage, allowing the improvement of operational variables that directly interact with the crushing process. In addition, this study considers the impact that occurs in both the process and operational continuity regarding the standardization of the system. In the first stage, a survey and analysis of historic operation data was carried out, which allowed the definition of benchmarking indicators. Subsequently, both modalities of operation were compared, monitoring processed tonnage and detentions related to operational failures. As a result, significant differences were observed in the performance of the critical line operating with expert control, with a 55% reduction in the detentions referred to operational failures. Added to this is the benefit of low cost and improved quality as the control provides an analysis of the variables in reduced time intervals, which is superior to human control.

  • 40.
    Ilankoon, I.M.S.K
    et al.
    Discipline of Chemical Engineering, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia. Global Asia in the 21st Century (GA21) Multidisciplinary Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Nan Chong, Meng
    Discipline of Chemical Engineering, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia. Global Asia in the 21st Century (GA21) Multidisciplinary Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia. Sustainable Water Alliance, Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia.
    Herath, Gamini
    Global Asia in the 21st Century (GA21) Multidisciplinary Platform, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia. School of Business, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan 47500, Malaysia.
    Moyo, Thandazile
    Department of Chemical Engineering, University of Cape Town, Rondebosch, South Africa.
    Petersen, Jochen
    Department of Chemical Engineering, University of Cape Town, Rondebosch, South Africa.
    E-waste in the international context: A review of trade flows, regulations, hazards, waste management strategies and technologies for value recovery2018In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 82, p. 258-275Article in journal (Refereed)
    Abstract [en]

    E-waste, or waste generated from electrical and electronic equipment, is considered as one of the fastest-growing waste categories, growing at a rate of 3–5% per year in the world. In 2016, 44.7 million tonnes of e-waste were generated in the world, which is equivalent to 6.1 kg for each person. E-waste is classified as a hazardous waste, but unlike other categories, e-waste also has significant potential for value recovery. As a result it is traded significantly between the developed and developing world, both as waste for disposal and as a resource for metal recovery. Only 20% of global e-waste in 2016 was properly recycled or disposed of, with the fate of the remaining 80% undocumented – likely to be dumped, traded or recycled under inferior conditions. This review paper provides an overview of the global e-waste resource and identifies the major challenges in the sector in terms of generation, global trade and waste management strategies. It lists the specific hazards associated with this type of waste that need to be taken into account in its management and includes a detailed overview of technologies employed or proposed for the recovery of value from e-waste. On the basis of this overview the paper identifies future directions for effective e-waste processing towards sustainable waste/resource management. It becomes clear that there is a strong divide between developed and developing countries with regard to this sector. While value recovery is practiced in centralised facilities employing advanced technologies in a highly regulated industrial environment in the developed world, in the developing world such recovery is practiced in a largely unregulated artisanal industry employing simplistic, labour intensive and environmentally hazardous approaches. Thus value is generated safely in the hi-tech environment of the developed world, whereas environmental burdens associated with exported waste and residual waste from simplistic processing remain largely in developing countries. It is argued that given the breadth of available technologies, a more systematic evaluation of the entire e-waste value chain needs to be conducted with a view to establishing integrated management of this resource (in terms of well-regulated value recovery and final residue disposal) at the appropriately local rather than global scale.

  • 41.
    Jonsén, Pär
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Lindkvist, Göran
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Pålsson, Bertil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Hammarberg, Samuel
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    First attempt to do a full-body modelling of a tumbling mill based on first principles2018In: Conference in Minerals Engineering / [ed] Jan Rosenkranz, Bertil Pålsson, Tommy Karlkvist, 2018, p. 71-84Conference paper (Refereed)
    Abstract [en]

    To efficiently model wet grinding in tumbling mills is a difficult task. Because of the complex behaviour of the pulp with free surfaces and large deformations, the difficulty is usually that the method to represent and reproduce its movements is demanding and time consuming. In this work, an investigation of the possibility to efficiently model and simulate the whole mill body, including the pulp and the charge, and its simultaneous interactions with both the charge and the mill structure is presented. This is done by the ICFD method, which is a Lagrange based method that gives the opportunity to efficiently model the pulp free surface flow, and its interaction with grinding balls and mill structure. Validation is done against experimentally measured driving torque signatures from an instrumented small-scale batch ball mill equipped with an accurate torque meter, and charge movements captured from high-speed video. Numerical results are in good agreement with experimental torque measurements.  

  • 42.
    Lishchuk, Viktor
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Koch, Pierre-Henri
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Pålsson, Bertil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Mattias, Gustafsson
    LKAB.
    Geometallurgical characterisation of Leveäniemi iron ore: unlocking the patterns2018In: Conference in Minerals Engineering / [ed] Jan Rosenkranz, Bertil Pålsson, Tommy Karlkvist, 2018Conference paper (Refereed)
    Abstract [en]

    Geometallurgy of iron ores aims at linking geological variability and responses in the beneficiation process by a wide usage of automated mineralogy, proxy metallurgical tests (e.g., Davis tube) and process simulation.

    In this study several patterns from iron ore processing, in context of their textural description, are revealed and modelling is attempted. The first one is an ore classification method with a novel quality estimator XLTU. The second one is an algorithm for predicting iron recovery in wet low intensity magnetic separator (WLIMS). The last one is predicting liberation distribution of iron oxides. Process variables are generated with a Davis tube and a WLIMS test. All streams are chemically characterised. Ore feed was studied for modal mineralogy and liberation distribution with QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy). Post-processing for detecting the patterns and data dependencies was done with multivariate statistics: principal component analysis (PCA), and projection to latent structures regression (PLS). The study was done on 13 apatite iron ore type samples from the Leveäniemi mine (LKAB).

    It is concluded that Davis tube test is better used only for marginal ores, since iron oxide minerals tend to be fully liberated in high grade magnetite massive ores after grinding. In addition, they will give high recovery and high mass pull in a Davis tube test.

    The developed models can be used in populating a production block model in the future. Furthermore, future work should cover larger variability of marginal ores in terms of Fe grades and modal mineralogy (e.g. feldspar, amphibole, apatite dominated). Variability of grain size distribution ought to be included into future studies.

  • 43.
    Vrkljan, Darko
    et al.
    Department of Mining and Metallurgy, University of Zagreb.
    Grbes, Anamarija
    Department of Mining and Metallurgy, University of Zagreb.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Frishammar, Johan
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Innovation and Design.
    Sand, Anders
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Berger, Gerald
    Wirtschaftsuniversität, Wien.
    Innovative processing: Final report including guidelines and recommendations for future policy development for innovation in mineral and metallurgical processing2018Report (Other academic)
    Abstract [en]

    ObjectivesThe aim of WP4 “Innovative Processing” is to elaborate how innovations in mineral and metallurgical processing are generated or taken up in different EU Member States and on EU‐level and how this is either facilitated or inhibited by policies and legislation on national or European level. The purpose oft he deliverable 4.3 is to complement the findings of D4.1 and D4.2 by carrying out additional interviews with representatives from different stakeholder groups (academia, industry, NGO’s and policymakers). The topics and questions of the questionnaire addressed the respondents’ perception of national and EU‐ and EU MS level mineral policies, gaps and needs with respect to innovation in mineral‐ and metallurgical processing. Questions for the questionnaire focus on previously identified innovations in mineral processing, metallurgical processing and metal recycling. Based on the input both from previous deliverables and from findings through the additional interviews and innovation cases, an analysis of needs and gaps as well as a SWOT analysis has been conducted. Recommendations for future development of mineral and metallurgical processing sector were evaluated.

    Main FindingsConclusions and recommendations for future policy development for innovation in mineral and metallurgical processing were developed based on a survey and a SWOT analysis.

    • Most of the mineral policies are addressing the entire mineral value chain. Several statutory provisions are related to mineral and metallurgical processing. National mineral policies are not very much addressing the mineral and metallurgical processing, while recycling is dislocated from mining/mineral legislation.
    • The sentiment amongst policy makers towards the raw materials industry has improved on EU level through a number of strategic policy initiatives (e.g. the Strategic Implementation Plan for Raw materials, the revised EU Industrial Policy Strategy, the Raw Materials Initiative).
    • The use of raw materials from secondary sources has been identified as being an integral part of the life cycle of materials.
    • Innovations in mineral and metallurgical processing are not supported at strategic and economic/investment level. The policy is neutral or inhibiting through long and uncertain permitting procedure, or is indifferent to innovation as to mineral and metallurgical processing.
    • The European knowledge and skills base in mineral and metallurgical processing has diminished during the past 20 years.
  • 44.
    Parian, Mehdi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Mwanga, Abdul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lamberg, Pertti
    Keliber Oy, Kaustinen.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Ore texture breakage characterization and fragmentation into multiphase particles2018In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 327, p. 57-69Article in journal (Refereed)
    Abstract [en]

    The ore texture and the progeny particles after a breakage in the comminution have been a subject of interest in mineral liberation studies and are the missing link between geology and mineral processing in the concept of geometallurgy. A new method called Association Indicator Matrix (AIM) established based on co-occurrence matrix was introduced to quantify the mineral association of ore texture and its progeny particles. The Association Indicator Matrix can be used as a criterion for classifying ore texture as well as analyzing breakage behavior of ore texture. Within the study, the outcome of breakage analysis with Association Indicator Matrix was used to forecast particle population of iron ore texture after crushing. The particle size of forecasted particles was taken from experimental and frequency of breakage in phases was defined based on Association Indicator and liberation of minerals. Comparison of liberation distribution of iron oxide minerals from experimental and forecasted population shows a satisfactory agreement.

  • 45.
    Parian, Mehdi
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Rosenkranz, Jan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Process simulations in mineralogy-based geometallurgy of iron ores2018In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855Article in journal (Refereed)
    Abstract [en]

    Mineral processing simulation models can be classified based on the level that feed stream to the plant and unit models are described. The levels of modelling in this context are: bulk, mineral or element by size, and particle. Particle level modelling and simulation utilises liberation data in the feed stream and is more sensitive to the variations in ore quality, specifically ore texture. In this paper, simulations for two texturally different magnetite ores are demonstrated at different modelling levels. The model parameters were calibrated for current run-of-mine ore and then in the simulation applied directly to the other ore. For the second ore, the simulation results vary between the different levels. This is because, at the bulk level, the model assumes minerals do not change their behaviour if ore texture or grinding fineness are changed. At the mineral by size level, the assumption is that minerals behave identically in each size fraction even if the ore texture changes. At the particle level, the assumption is that similar particles behave in the same way. The particle level approach gives results that are more realistic and it can be used in optimisation, thus finding the most optimal processing way for different geometallurgical domains.

  • 46.
    Lishchuk, Viktor
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Miroshnikova, Elena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mathematical Science.
    Simulation of a Mining Value Chain with a Synthetic Ore Body Model: Iron Ore Example2018In: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 8, no 11, article id 536Article in journal (Refereed)
    Abstract [en]

    Reconciliation of geological, mining and mineral processing information is a costly and time demanding procedure with high uncertainty due to incomplete information, especially during the early stages of a project, i.e., pre-feasibility, feasibility studies. Lack of information at those project stages can be overcome by applying synthetic data for investigating different scenarios. Generation of the synthetic data requires some minimum sparse knowledge already available from other parts of the mining value chain, i.e., geology, mining, mineral processing. This paper describes how to establish and construct a synthetic testing environment, or “synthetic ore body model” by integrating a synthetic deposit, mine production, constrained by a mine plan, and a simulated beneficiation process. The approach uses quantitative mineralogical data and liberation information for process simulation. The results of geological and process data integration are compared with the real case data of an apatite iron ore. The discussed approach allows for studying the implications in downstream processes caused by changes in upstream parts of the mining value chain. It also opens the possibility of optimising sampling campaigns by investigating different synthetic drilling scenarios including changes to the spacing between synthetic drill holes, composite length, drill hole orientation and assayed parameters.

  • 47.
    Bauer, Tobias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andersson, Joel
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. LKAB, Malmberget.
    Sarlus, Zimer
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Lund, Cecilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Kearney, Thomas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Structural controls on the setting, shape and hydrothermal alteration of the Malmberget IOA deposit, northern Sweden2018In: Economic geology and the bulletin of the Society of Economic Geologists, ISSN 0361-0128, E-ISSN 1554-0774, Vol. 113, no 2, p. 377-395Article in journal (Refereed)
    Abstract [en]

    The Malmberget iron oxide-apatite (IOA) deposit in northern Sweden is one of the largest underground iron ore mine operations in the world with estimated ore reserves in 2015 of 346 million metric tons (Mt) at 42.5% Fe. The underground operation is concentrated in 10 orebodies of 5 to 245 Mt each, which currently produce 17.4 Mt of apatite iron ore per year. Structural investigations were combined with data on hydrothermal mineral assemblages in order to reconstruct the relative timing of ore-forming, deformation, and overprinting hydrothermal events. The results improve the understanding of structural geometries, relationships, and control on orebody transposition in the deposit. A first compressional event (D1) around 1.88 Ga represents the main metamorphic event (M1) in the area and was responsible for a strong transposition of potential primary layering and the orebodies and led to the formation of a composite S0/1 fabric. A subsequent F2 folding event around 1.80 Ga resulted in the formation of an open, slightly asymmetric synform with a steeper southeast limb and a roughly SW-plunging fold axis. The result of structural modeling implies that the ore formed at two separate horizons. The folding was accompanied by stretching, resulting in boudinage of the iron orebodies. D2-related high-strain zones and syntectonic granites triggered the remobilization of amphibole, biotite, magnetite, and hematite and controlled the formation of iron oxide-copper-gold (IOCG)-type hydrothermal alteration, including an extensive K-feldspar alteration accompanied with sulfides, scapolite, and epidote. This shows a distinct time gap of at least 80 m.y. between the formation of iron oxides and sulfides. Brittle structures and the lack of an axial planar parallel fabric in conjunction with previous results suggest upper crustal, low-pressure, and high-temperature conditions during this D2 deformation phase, indicating a hydrothermal event rather than a purely regional metamorphic compression. It is proposed in the present study that the Malmberget IOA deposit was deformed and metamorphosed during a 1.88 Ga crustal shortening event. Moreover, the Malmberget IOA deposit was affected by a 1.8 Ga folding and hydrothermal event that is related to a regional IOCG overprint.

  • 48.
    Nazari, S.
    et al.
    School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Shafaei, S.Z.
    School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran.
    Shahbazi, B.
    Department of Mining Engineering, Tarbiat Modares University, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Study relationships between flotation variables and recovery of coarse particles in the absence and presence of nanobubble2018In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 559, p. 284-288Article in journal (Refereed)
    Abstract [en]

    Recent investigations indicated that using nanobubbles (NBs) in flotation separation of fine particles (<25 μm) has several advantages; however, a detail study on performances of various flotation parameters (such as hydrodynamic variables and particle properties) and their impacts on recovery of coarse particles (>100 μm) in the presence of NBs have not been fully understood. This work was explored how NBs can change impacts of Reynolds number, conventional flotation bubbles (CBs), air flow rate and particle sizes on flotation recovery of coarse particles (−425 + 106 μm). Several flotation experiments were carried out by using pure quartz in the presence and absence of NBs. Kendall’s tau (τ) as an accurate statistical method was introduced and applied through the provided dataset from the experiments to assess the impacts of NBs. In the absence of NBs; τ assessments demonstrated that there are negative correlations between particle size, air flow rate, Reynold number and recovery (τ ∼ −0.81, −0.18 and −0.12, respectively), and a positive relationship between CBs and recovery (τ ∼ 0.08). In general, results indicated that recovery of coarse particles was increased by ∼14% (on average) in the presence of NBs; however, the magnitude of relationships was not changed (just correlations between Reynolds and CBs vs. recovery were changed: τ ∼ −0.17 and 0.13, respectively). Assessing the simultaneous impacts of Re and CBs on recovery showed that in the presence of NBs; the highest recovery (on average) may receive in lower Re values and higher CB sizes in comparison with in the absence of NBs. Taking all these interactions into consideration, it can be concluded that increasing the rate of bubble-particle attachment and decreasing the impact of Re can be the main reasons for the enhancement of coarse particle recovery in the presence of NBs.

  • 49.
    Bahrami, Ataallah
    et al.
    Department of Mining EngineeringUrmia UniversityUrmiaIran.
    Ghorbani, Yousef
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Mirmohammadi, Mirsaleh
    School of Mining EngineeringUniversity of TehranTehranIran.
    Sheykhi, Behnam
    Department of Mining EngineeringUrmia UniversityUrmiaIran.
    Kazemi, Fatemeh
    Department of Mining EngineeringUrmia UniversityUrmiaIran.
    The beneficiation of tailing of coal preparation plant by heavy-medium cyclone2018In: International journal of coal science & technology, ISSN 2095-8293, Vol. 5, no 3, p. 374-384Article in journal (Refereed)
    Abstract [en]

    Dense-medium cyclones have been used for beneficiation of fine particles of coal. In this study, the usability of cyclones in the beneficiation of tailings of a coal preparation plant was investigated. For this purpose, separation tests were conducted using spiral concentrator and heavy medium cyclones with the specific weight of medium 1.3–1.8 (g/cm3) on different grading fractions of tailing in an industrial scale (the weight of tail sample was five tons). Spiral concentrator was utilized to beneficiate particles smaller than 1 mm. In order to evaluate the efficiency of cyclones, sink and float experiments using a specific weight of 1.3, 1.5, 1.7 and 1.9 g/cm3, were conducted on a pilot scale. Based on the obtained results, the recovery of floated materials in cyclones with the specific weight of 1.40, 1.47 and 1.55 g/cm3 are 17.75%, 33.80%, and 50%, respectively. Also, the cut point (ρ50), which is the relative density at which particles report equally to the both products are 1.40, 1.67 and 1.86 g/cm3. The probable errors of separation for defined specific weights for cyclones are 0.080, 0.085 and 0.030, respectively. Also, the coefficients of variation was calculated to be 0.20, 0.12 and 0.03. Finally, it could be said that the performance of a cyclone with a heavy medium of 1.40 g/cm3 specific weight is desirable compared with other specific weights.