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  • 1.
    Abdel-Khalek, N.A.
    et al.
    Central Metallurgical Research and Development Institute (CMRDI), Helwan, Cairo.
    Yassin, K.E.
    Central Metallurgical Research and Development Institute (CMRDI), Helwan, Cairo.
    Kota, Hanumantha Rao
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Kandel, A-H
    Chemistry Department, Faculty of Science, Helwan University.
    Effect of starch type on selectivity of cationic flotation of iron ore2012In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 121, no 2, p. 98-102Article in journal (Refereed)
    Abstract [en]

    Cationic flotation is one of the most widely accepted technologies for upgrading siliceous iron ore using polysaccharides (mainly starches) as depressing agents for iron bearing minerals while floating silica with amines. In this paper, a group of starches are investigated as depressants for haematite. These starches are wheat, corn, rice, potato and dextrin. The role of starch type on the selectivity of the separation process has been studied through zeta potential, adsorption measurements as well as flotation tests. The effects of type of starch and pH of the medium have been studied. The results indicate that the selectivity of the separation process is strongly affected by the type of starch used, where better results are obtained with corn starch or wheat starch in comparison to the other types. Fourier transform infrared spectroscopy measurements indicated that the interaction between starches and haematite surface is intermolecular interaction

  • 2.
    Albertsson, Galina Jelkina
    et al.
    Department of Materials Science and Engineering, Royal Institute of Technology, Division of Materials Process Science, Royal Institute of Technology (KTH).
    Teng, Lidong
    Division of Materials Process Science, Royal Institute of Technology (KTH).
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Effect of basicity on chromium partition in CaO-MgO-SiO2-Cr 2O3 synthetic slag at 1873 K2014In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 123, no 2, p. 116-122Article in journal (Refereed)
    Abstract [en]

    The objective of the present work is to get an understanding of the phase relationships in the CaO-MgO-SiO2-Cr2O3 system with a view to control the precipitation of Cr-spinel in the slag phase. The equilibrium phases in CaO-MgO-SiO2-Cr2O3 slag system at 1873 K (1600°C) have been investigated experimentally and compared with the results from thermodynamic calculations. The Cr2O 3 and MgO contents in the slag were fixed at 6 and 8 wt-% respectively. The basicity (CaO/SiO2) of slag was varied in the range 1·0-2·0. A gas/slag equilibrium technique was adopted to synthesise the slag at a high temperature in air. The samples were heated to and soaked at 1873 K (1600°C) for 24 h in order to achieve the equilibrium state and subsequently quenched in water. The chromium distribution and phase compositions in the quenched slag were studied using scanning electron microscope wavelength dispersive spectroscopy and X-ray diffraction techniques. FactSage software was used for the phase equilibrium calculations. The experimental results obtained from the present work were compared with the calculation results from FactSage software. It was found that the spinel formation at 1873 K (1600°C) is favoured in the slag basicity range 1·0-1·4

  • 3.
    Andersson, Charlotte
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Mostaghel, Sina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    The need for fundamental measurements for a sustainable extraction of metals2011In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 120, no 2, p. 199-204Article in journal (Refereed)
    Abstract [en]

    The increased need for efficient material processing and efficient utilisation of more complex raw materials and the need for recycling or reusing byproduct and waste streams, are all increased challenges in material processing. To cope with these challenges, there is a need for new basic physical and thermodynamic data. The present paper gives four examples, as well as preliminary data, of areas where increased knowledge of fundamental parameters will increase the possibility for a sustainable extraction of metals. The examples include measurement of solubility of pure individual slag minerals, determination of distribution of leachable elements between different mineralogical phases in slag, influence of alumina on liquidus temperature of a copper slag and thermal diffusivity measurements in magnetite based iron ore pellets, all important in different ways to increase the sustainability of the respective materials involved

  • 4.
    Gao, Ming-Wei
    et al.
    Luleå tekniska universitet.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Simulation of batch grinding of iron ore1990In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 99, p. 142-146Article in journal (Refereed)
    Abstract [en]

    A batch-grinding process treating a natural magnetite ore was simulated by a population-balance model. Different methods of determining selection and breakage functions for the ore were investigated. Grinding tests were performed with seven monosize fractions in a pilot-scale ball-mill. The back-calculated selection function was compared with experimentally measured values of the selection function, S, and the breakage functions so determined were checked against the results of the simulation. It appears that if the breakage functions of a material are not normalizable, it is necessary to carry out a sufficient number of monosize grinding tests to allow reliable selection and breakage functions to be estimated. Graphs. 8 ref.--AA

  • 5. Hosseini, S. H.
    et al.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Smithsonite flotation using potassium amyl xanthate and hexylmercaptan2006In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 115, no 2, p. 107-112Article in journal (Refereed)
    Abstract [en]

    The influence of potassium amyl xanthate (KAX) and hexylmercaptan (HM) adsorption on smithsonite surface at various concentrations were investigated through using zeta potential, contact angle, microflotation and diffuse reflectance FTIR studies at different pH. The zeta potential measurements of KAX showed that the adsorption of ionic charge (more negative charge after KAX treatment) takes place on the surface of pure crystalline smithsonite. The charges vary between −38 and −45 mV at pH 10·5. Flotation results using potassium amyl xanthate reveal that the maximum recovery of 81·3% and the maximum contact angle of 98·7° occurs at pH 10·5 at KAX concentration of 2·96 × 10−3M in sodium sulphide (2·6 × 10−2M) and copper sulphate (9·4 × 10−3M) solutions. The highest recovery and contact angle for flotation by means of HM occurs at pH 9 at values of 78·6% and 92·3° respectively with HM concentration 1·1 × 10−2M. The FTIR spectra studies of smithsonite conditioned by KAX confirmed the adsorption of KAX and the presence of CS2 on smithsonite surface. The FTIR spectra in HM studies showed the adsorption of RS− on the oxidised zinc surface and the S-H bond in the mercaptan is destroyed on adsorption. The comparison between the results using anionic collectors showed that the presence of different amounts of reagents on smithsonite surface in two cases confer different degree of hydrophobicity on the smithsonite surface.

  • 6.
    Hosseini, S. H.
    et al.
    Islamic Azad University, Tehran South Campus.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Studies on selective flotation of smithsonite from silicate minerals using mercaptans and one stage desliming2011In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 120, no 2, p. 79-84Article in journal (Refereed)
    Abstract [en]

    The separation of oxide zinc mineral from silicate minerals in smithsonite mineral, associated silicate minerals and oxide zinc ore samples was assessed using methyl mercaptan (CH3SH), ethyl mercaptan (C2H 5SH) and hexyl mercaptan (C6H13SH; HM) as collectors. The optimal flotation conditions were defined through Hallimond tube, contact angle and batch flotation and the results were applied to a natural Angooran oxide zinc ore. The microflotation and artificial mixture flotation results showed a maximum of 78% flotation recovery using HM. Selective flotation of oxide zinc ore was also accomplished by using an HM collector at pH 9. The flotation recovery was 55% without desliming. When the initial feed was deslimed before bench scale flotation tests, the recovery increased from 55 to 75%with 22·5%zinc content in the concentrate.Whenmethylmercaptan or ethyl mercaptan was used, lower zinc recoveries and grades compared to HM flotation were achieved

  • 7.
    Hosseini, S.H.
    et al.
    Islamic Azad University.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Smithsonite flotation using mixed anionic/cationic collector2009In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 118, no 3, p. 186-190Article in journal (Refereed)
    Abstract [en]

    The surface interaction and adsorption of the components in a mixture of surfactants are of considerable interest for both practical and theoretical reasons. The flotation behaviour of smithsonite in the presence of sodium sulphide (Na2S) and a mixture of potassium amyl xanthate (KAX) and dodecylamine (DDA) and its adsorption on smithsonite surface at various concentration ratios have been investigated using zeta potential, contact angle, microflotation and diffuse reflectance FTIR studies. The smithsonite mineral has weak response to flotation in the presence of KAX alone as a collector. The presence of KAX enhanced the amine flotation recovery in the presence of sodium sulphide. The flotation results using mixed collectors showed the maximum recovery and contact angle were 95.5% and 104° at pH 12 respectively. The FTIR spectra revealed the coadsorption as amine - xanthate complex when mixed collector is used. The presence of KAX increased the DDA adsorption due to decrease in the electrostatic head - head repulsion between the two adjacent surface ammonium head group cations because the anionic KAX sitting between these two cations screens the electrostatic repulsion and increased the lateral tail-tail hydrophobic bonds.

  • 8. Lager, Thomas
    et al.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Separation of antimony mineral impurities from complex sulphide ores1990In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 99, p. 54-61Article in journal (Refereed)
  • 9.
    Lennartsson, Andreas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Engström, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Thermodynamic process modelling of black copper addition to a Peirce-Smith converter: effect on the distribution of antimony and bismuth2014In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 123, no 3, p. 157-164Article in journal (Refereed)
    Abstract [en]

    The effect of adding black copper, originating from treating waste electrical and electronic equipment (WEEE), to a Peirce-Smith converter has been investigated by using a thermodynamic process model. The model was formulated, by the authors, in an earlier publication and expanded, in the present work, to include the minor elements antimony and bismuth. The results show that the model describes the distribution of Bi well, whereas the distribution of Sb is not described as well and should only be used for trends. Addition of black copper lowers the removal of Bi and Sb compared to a converter cycle without addition. To maintain a good removal of Bi and Sb, black copper should be added as early as possible during a converter cycle.

  • 10.
    Minz, Friederike
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bolin, Nils-Johan
    Division of Process Technology, Boliden Mineral AB.
    Lamberg, Pertti
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Wanhainen, Christina
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Bachmann, Kai
    Helmholtz Zentrum Dresden-Rossendorf, Helmholtz-Institute-Freiberg for Resource Technology, Freiberg.
    Gutzmer, Jens
    Helmholtz Zentrum Dresden-Rossendorf, Helmholtz-Institute-Freiberg for Resource Technology, Freiberg.
    Particle-based Sb distribution model for Cu–Pb flotation as part of geometallurgical modelling at the polymetallic Rockliden deposit, north-central Sweden2017In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 126, no 4, p. 212-223Article in journal (Refereed)
    Abstract [en]

    The polymetallic Cu–Zn ore of the Rockliden massive sulphide deposit in the Skellefte District in north-central Sweden contains a number of deleterious elements in relevant concentrations. Of particular concern is the amount of antimony (Sb) reporting to the Cu–Pb concentrate. The aim of this study was to compare different model options to simulate the distribution of Sb minerals in a laboratory flotation test based on different degrees of details in the mineralogical information of the flotation feed. Experimental data obtained from four composites were used for the modelling and simulation. The following different simulation levels were run (sorted from least to highest level of detail of their mineralogical information): chemical assays, unsized bulk mineralogy, sized bulk mineralogy and particle information. It was shown that recoveries simulated based on bulk mineralogy are mostly within the error margin acceptable in the exploration stage of the Rockliden deposit. Unexpected high deviation in the simulation using particle information from the original recovery has been partly attributed to the fact that recovery of non-liberated particles cannot be modelled appropriately in the present version of the modelling and simulation software. It is expected that the implementation of full particle information in simulation will improve the Sb distribution model for the mineralogically complex Rockliden deposit.

  • 11.
    Mostaghel, Sina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Matsushita, Taishi
    Kungliga tekniska högskolan, KTH.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Seetharaman, Seshadri
    Kungliga tekniska högskolan, KTH.
    Influence of alumina on physical properties of an industrial zinc-copper smelting slag: Part 1: Viscosity2013In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 122, no 1, p. 42-48Article in journal (Refereed)
    Abstract [en]

    The rotating cylinder method was applied to measure the viscosities of an industrial iron silicate slag and mixtures of this slag with 5, 10 and 15 wt-% alumina addition, in temperature range 1100–1300°C. The measured viscosities were compared with the predicted values using two of the commercially available software products for viscosity calculations, namely Thermoslag®1.5 and FactSageTM6.2. As the models can only predict viscosities for a solid free melt, obtained values by FactSageTM6.2 were modified using the Einstein–Roscoe equation. Results show that aluminium behaves as a network former cation in this type of slag, and by increasing the alumina concentration, the melt becomes progressively polymerised. Consequently, the viscosity of the slag increases at a given temperature, which is supported by thermodynamic predictions. According to the modified FactSageTM6.2 calculations, the viscosity of the solid containing slag increases from 2.1 to 5.5 poise at the industrial operating temperature (∼1250°C).

  • 12.
    Mostaghel, Sina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Matsushita, Taishi
    Kungliga tekniska högskolan, KTH.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Seetharaman, Seshadri
    Kungliga tekniska högskolan, KTH.
    Influence of alumina on physical properties of an industrial zinc-copper smelting slag: Part 2: Apparent density, surface tension and effective thermal diffusivity2013In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 122, no 1, p. 49-55Article in journal (Refereed)
    Abstract [en]

    Apparent density, surface tension and effective thermal diffusivity of an industrial iron–silicate based slag and mixtures of this slag with 5, 10 and 15 wt-% alumina addition were measured using the sessile drop and the laser flash techniques respectively. A comparison is made between corresponding values obtained from the commonly applied models and the experimental measurements. Results show that increasing the alumina concentration in slag increases the degree of polymerisation of the melt and, consequently, its effective thermal diffusivity. By alumina addition to the system, the surface tension increases progressively from 338 mN m−1, in the reference slag sample, to 488 mN m−1, in the mixture of slag and 15 wt-% alumina addition. The apparent density of the liquid–solid containing slag is continuously decreased due to the increased alumina concentration. However, the effect is more pronounced between 8 and 12 wt-% total alumina content in the slag.

  • 13.
    Mostaghel, Sina
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Matsushita, Taishi
    Kungliga tekniska högskolan, KTH.
    Samuelsson, Caisa
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Björkman, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Seetharaman, Seshadri
    Kungliga tekniska högskolan, KTH.
    Influence of alumina on physical properties of an industrial zinc-copper smelting slag: Part 3: Melting behaviour2013In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 122, no 1, p. 56-62Article in journal (Refereed)
    Abstract [en]

    A combination of different experimental techniques and thermodynamic calculations has been used to investigate the melting behaviour of an industrial iron silicate slag and mixtures of this slag with 5, 10 and 15 wt-% alumina addition. Differential scanning calorimetry (DSC) and thermooptical observation were applied to monitor the solidus temperature and softening behaviour of the samples respectively. Estimation of the liquidus temperature was made using the second derivative of activation energies for viscous flow, with respect to temperature. All experimentally detected values were compared to predictions made using the FactSageTM6.2 thermodynamic package. Results show that as the slag lies in the fayalite primary phase field, the liquidus temperature decreases due to the increased alumina concentration. In the hercynite primary crystallisation phase field, however, alumina addition to the system increases the liquidus temperature. The solidus temperature does not vary significantly due to the current changes in the total alumina content of the slag.

  • 14.
    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.

  • 15.
    Rao, K. Hanumantha
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Samskog, Per-Olof
    Forssberg, Eric
    Pulp chemistry of the flotation of phosphate gangue from magnetite fines1990In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 99, p. 147-156Article in journal (Refereed)
  • 16.
    Su, Fenwei
    et al.
    Luleå tekniska universitet.
    Rao, K. Hanumantha
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Forssberg, Eric
    Samskog, Per-Olof
    Dephosphorization of magnetite fines: Part 1: evaluation of flotation kinetic models1998In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 107, p. C95-C102Article in journal (Refereed)
    Abstract [en]

    Dephosphorization of magnetite fines by flotation in such a way as to minimize the fatty acid coating left on the magnetite surfaces is the principal technical challenge facing the mineral processing division of LKAB, Sweden. Modelling of flotation kinetics enables the influence of chemical and operational variables on apatite flotation from magnetite fines to be predicted. Five typical first-order flotation kinetic models are evaluated by statistical techniques, after an estimation of model parameters by a nonlinear least-squares fitting program, with use of the authors' own results and results taken from the literature. Evaluation of the models is based on two aspects: goodness of fit to the experimental results and suitability to describe the flotation behaviour. The first-order models with a rectangular distribution of floatabilities and with fast and slow floating components (F-S model) gave an excellent fit to the experimental results of apatite flotation when compared with the other models, the latter being superior not only in the goodness of fit to apatite flotation and other mineral flotation results but also in its description of flotation behaviour. The kinetic parameters (percentage recoveries and rate constants of fast and slow floating particles) in the F-S model have a physical significance and can thus be used for qualitative as well as quantitative interpretation of flotation performance. The influence of collector dose can be effectively included in the F-S model by making realistic simplifications and relating the collector dose to the fraction of slow floating particles. The ratio of fast and slow rate constants can be used to describe the selectivity of apatite flotation from magnetite.

  • 17.
    Su, Fenwei
    et al.
    Luleå tekniska universitet.
    Rao, K. Hanumantha
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Forssberg, Eric
    Samskog, Per-Olof
    Dephosphorization of magnetite fines: Part 2: Influence of chemical variables on flotation kinetics1998In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 107, p. C103-C110Article in journal (Refereed)
    Abstract [en]

    The influence of chemical and operational variables on the kinetics of apatite flotation from magnetite was investigated through batch flotation tests in a specially designed, temperature-controlled cell. The significance for the apatite flotation kinetics of four variables - collector, dispersant, pulp pH and temperature - and their interactions was examined through experiments conducted according to a full factorial design. The kinetic parameters of a first-order model with fast and slow floating distribution were utilized in judging the influence of reagent dosage on flotation performance. Statistical tests on phosphorus kinetic data show that collector and dispersant doses have a significant effect on phosphorus recovery. However, pulp temperature is the dominant factor for flotation rate. Increase in pulp temperature increases the flotation rate. The recovery of phosphorus increases with increasing collector dose at a given dispersant dose; however, the flotation rate decreases at doses of collector exceeding 65 g/t when the dispersant is at a higher level. The effect of dispersant dosage on flotation rate is observed to be nonlinear and quite complex owing to the interaction effects between collector and dispersant doses. The maximum recovery of phosphorus with minor loss of magnetite concentrate was obtained at pH 9, with either 30 or 65 g/t collector. The optimum flotation conditions were 65 g/t collector, 350 g/t dispersant, pH 8-9 and a pulp temperature of about 20 deg C

  • 18.
    Zeng, Yigen
    et al.
    Luleå University of Technology.
    Forssberg, Eric
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Application of digital signal processing and multivariate data analysis to vibration signals from ball-mill grinding1993In: Transactions of the Institution of Mining and Metallurgy Section C - Mineral Processing and Extractive Metallurgy, ISSN 0371-9553, E-ISSN 1743-2855, Vol. 102, no Jan-Apr, p. 39-43Article in journal (Refereed)
    Abstract [en]

    During mechanical grinding high-intensity vibration is emitted that contains information on the operating state of the mill. To study the influence of operating parameters on the vibration signature tests were performed with a laboratory ball-mill. Five operating parameters were considered: mill speed, powder filling (as a percentage of voidage), pulp density, grinding period, and pulp temperature. Vibration signals were detected by an accelerometer, amplified by a portable vibrometer and recorded with a digital audio tape recorder. A digital oscilloscope was used to convert the signals into an IBM-compatible data format.

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