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  • 101.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A New Insight Into Oxidation Mechanisms of Sulphide Minerals2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sulphide minerals during grinding was examined. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite ((Zn, Fe) S), and galena (PbS) generated H2O2 in pulp liquid during wet grinding and also when the freshly ground solids are placed in water immediately after dry grinding. Pyrite produced more H2O2 than other minerals and the order of H2O2 production by the minerals was found to be pyrite > chalcopyrite > sphalerite > galena. The pH of the water influenced the extent of hydrogen peroxide formation with greater amounts of H2O2 produced at highly acidic pH. Furthermore, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite-galena on the formation of H2O2 showed increasing H2O2 formation with increasing pyrite fraction. There is clear correlation of the amount of H2O2 production with the rest potential of the sulphide minerals; the greater the rest potential of a mineral the greater the formation of H2O2. This study highlights the necessity of revisiting the electrochemical and/or galvanic interactions between sulphide minerals, and interaction mechanisms between pyrite and other sulphide minerals in terms of their flotation behaviour in the context of inevitable H2O2 existence in the pulp liquid

  • 102.
    Lund, Cecilia
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lindberg, Therese
    LKAB, Research & Development, 983 81 Malmberget.
    A new method to quantify mineral textures for geometallurgy2014Konferensbidrag (Övrigt vetenskapligt)
  • 103.
    Jonsén, Pär
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Häggblad, Hans-Åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    A novel method for modelling of interactions between pulp, charge and mill structure in tumbling mills2014Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 63, s. 65-72Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Modelling the pulp fluid and its interaction with both the charge and the mill structure is an interesting challenge. The interaction is normally modelled with a combination of CFD and DEM, where the DEM particles (grinding balls) create the structure through which the fluid penetrates, and in its turn creates forces on the grinding balls. However, in a tumbling mill, many free surfaces are found and that limits the use of CFD. An alternative computational approach is here necessary.The smoothed particle hydrodynamic (SPH) method has earlier been used to model a ball charge and its interaction with the mill structure. In the present contribution, a SPH description of the pulp fluid is introduced. The lifters and the lining are still modelled with the finite element method (FEM), and the grinding balls with DEM. This combined computational model makes it possible to predict pressure within the pulp fluid. It is also possible to predict how the dampening effect of the pulp liquid is affected by its viscosity and density. The charge induced torque in a laboratory-scale ball mill is used for validation, and the mechanical shock waves travelling in the mill system are described

  • 104.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    A way forward in process mineralogy: using automated mineralogy for modelling and simulating beneficiation processes2014Konferensbidrag (Övrigt vetenskapligt)
  • 105.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Karlkvist, TommyLuleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Conference in Minerals Engineering 20142014Samlingsverk (redaktörskap) (Övrigt vetenskapligt)
  • 106.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Design and Development of Mineral Structure Specific Collectors in Flotation2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The success of mineral flotation processes depends on the hydrophobization of the surface for the desired mineral particles whilst keeping, or making, all other minerals hydrophilic. This is achieved by adding several reagents to the flotation pulp to adsorb selectively at the mineral/water interface. The reagents (surface active agents) which selectively adsorbs on minerals to be floated are called collectors. It is realized that many of these commonly used reagents are highly toxic and often potential threats to the environment. Use of many of theseconventional chemicals will therefore be restricted soon and must eventually be stopped. An immediate effort is necessary to develop alternative eco-friendly reagents in order to continue to extract valuable minerals from ores. In addition, with the steady depletion of high grade, relatively easy to process ores, the mineral industry is confronted with a challenging task of finding more efficient techniques so as to exploit low grade, complex and disseminated typeof ore deposits and old tailing dumps. The development of new selective and environmentally acceptable substances containing almost tailor-made reagents is thus inevitable for sustainability. Several known chelating agents have been appropriately modified to make those behave as selective flotation collectors with some degree of success. The problem is that almost all of the chelating groups form complexes with almost all of the transition and many non-transition metals. As a consequence, absolute selectivity does not exist. Besides beingunsatisfactory from a scientific viewpoint, it assumes that the metal ion specificity observed for a functional group in bulk aqueous system would remain valid during surface chelation at the interface, while in actual practice, the specificity based on metal ion is neither valid nor useful where the cations participating in the complexation reactions are the same, for example separation among the calcium minerals.It is clear that a selective reagent should be based on the reagent interactions not merely with the metal ion on the surface, but with the whole surface. It is more appropriate to design reagents having functional groups so spaced that those are compatible with the relative positions of the metal ion sites available on the surface, that is, to design not just metalspecificbut structure-specific reagents. The understandings of molecular interactions involved in the recognition of surfaces by organic molecules in biomineralization process suggest the possibility of reagents specific to the crystal structure. These understandings have been successfully applied to the rational design and synthesis of molecules either for the control of crystal morphology or to inhibitcrystal growth processes through the recognition of specific crystal surfaces. The idea of molecules consisting of two groups having appropriate spacing between them to achieve structural compatibility during interaction with surface exhibit structure-specificity is of direct relevance to the reagents selectivity in flotation processes. The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying spacing between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant withthe same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite, calcite and fluorite mineral surfaces was studied using Hallimond tube flotation, ζ-potential and FTIR measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much moreselective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ-potential and infrared spectroscopy data. Our investigation revealed that it is possible to design and develop mineral specific reagents in flotation.

  • 107.
    Patra, Anuttam
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Karlkvist, Tommy
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rao, Hanumantha
    Fredriksson, Andreas
    LKAB.
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Design and development of novel mineral-specific collectors for flotation2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Almost all of the flotation reagents used today were discovered by continued application of empirical methods and/or trial and error experimentation. Moreover, with the metal-ion specific approach used so far, it is difficult to separate the minerals containing the same constituent metal ion. A critical assessment of molecular recognition processes involved in biomineralization suggested the possibility of using reagents which are surface specific. The concept that the molecules consisting of two or more functional groups having appropriate spacing between those so as to achieve structural/stereochemical compatibility during interaction with the mineral surface exhibit structure-specificity is thought to be extended to the design of specific collectors in flotation processes. In the present study, for the first time, a rational design of surface active molecules, and thereby the recognition of crystal faces (of minerals) by these molecules through structural and stereochemical matching is being utilized successfully to selectively float various minerals. For this purpose, carboxylate-based collectors (for mineral specific flotation of calcium minerals) as well as xanthate-based collectors (for mineral specific flotation of sulphide minerals) with a fixed alkyl chain length but having two functional groups with varying geometrical distances (separated by a spacer of one, two and three carbon atoms) between them have been synthesized. In this article, we have discussed the design, synthesis, purification of these novel mineral specific collectors as well as their important solution parameters in relation to flotation processes.

  • 108.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Development of Novel Reagents for Mineral-Specific Flotation2014Konferensbidrag (Refereegranskat)
  • 109.
    Jonsén, Pär
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Häggblad, Hans-Åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Tano, Kent
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Berggren, Andreas
    Boliden Mineral AB, New Boliden AB.
    Development of physically based tumbling mill models2014Ingår i: Proceedings of XXIII International Mineral Processing Congress: XXVII, Santiago, Chile 20-24 October 2014, Santiago: IMPC , 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Numerical modelling of grinding in tumbling mills is traditionally done with the discrete element method (DEM). The grinding balls are then represented by DEM particles and the mill structure is considered rigid. To include more physical phenomena several numerical methods can be combined. One important improvement is to include the mill structure response, using the finite element method (FEM). The interaction between charge and lining can then be studied in detail. The pulp can also be included using a particle-based continuum method e.g. smoothed particle method (SPH). The strength of SPH lies in modelling of free surface flows and very large deformations and it is suited to model simultaneous fluid and granular flow. Still, the coarse particles (grinding balls) in the charge are suitable to be model using DEM. Each of these methods has their strength and weaknesses, but combined they can successfully mimic the main features of the charge movement. With these numerical tools the complex interaction between the different components of the grinding process; pulp, charge, lining and the mechanical behaviour of the mill, can be studied together. This work will present novel numerical approaches to model, simulate and validate charge behaviour in tumbling mills. These numerical models give possibilities to better understand the physical and mechanical behaviour of particulate material systems during grinding in a tumbling mill. This is important in order to develop and optimise future high-capacity grinding circuits and save energy.

  • 110.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bolin, Nils-Johan
    Boliden Mineral AB, Luleå tekniska universitet.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Bachmann, Kai
    TU Bergakademie Freiberg, Helmholtz Institute Freiberg for Resource Technology.
    Gutzmer, Jens
    TU Bergakademie Freiberg, Helmholtz Institute Freiberg for Resource Technology.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Distribution of Sb-bearing minerals in the Cu and Zn flotation of Rockliden massive sulphide ore in north-central Sweden2014Konferensbidrag (Övrigt vetenskapligt)
  • 111.
    Sand, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Education Related to Mineral Raw Materials in the European Union: D3.1 Preliminary report on available study programmes and existing skill shortages2014Rapport (Övrigt vetenskapligt)
  • 112.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Effect of grinding environment on galena flotation2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The participation of H2O2 in oxidation of the galena mineral and as a result in decreasing of the concentrate recovery of galena mineral has not yet been shown. In this study the effect of two types of grinding media in wet and dry grinding on the formation of hydrogen peroxide and galena flotation was investigated. Laboratory stainless steel ball mill (Model 2VS, CAPCO Test Equipment, Suffolk, UK) was used for grinding galena with mild steel and stainless steel media. Galena ground with mild steel generated more hydrogen peroxide than galena ground with stainless steel media. Galena ground with mild steel has a lower galena recovery than galena ground with stainless steel media. Solutions of 2, 9-dimethyl-1, 10-phenanthroline (DMP) were used for estimating H2O2 amount in pulp liquid with DU® Series 700 UV/Vis Scanning Spectrophotometer. This study highlights the necessity of relooking into galvanic interaction mechanisms between the grinding medium and galena in terms of its flotation behavior.

  • 113.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Evaluation of the applicability of ultrasonic velocity profiling in conditions related to wet low intensity magnetic separation2014Ingår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 62, s. 2-8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The internal material transport and selection processes of the wet low-intensity magnetic separators (LIMS) are poorly understood; this calls for improved measurement techniques. In this work an ultrasonic velocity profiling (UVP) technique for measuring how material flow velocity varies with penetration depth is presented. A measurement depth of just a couple of centimetres would greatly improve the understanding of the separation process in a LIMS.When applied to flows of mineral suspensions with high volumetric solids concentration, similar to those in the separators, UVP is unique in combining:•Non-intrusive measurements.•Operates using just one sensor element (transducer).•Relatively good spatial resolution.•Penetrates opaque suspensions.•Fast sampling rate.Here, flows are studied in a rectangular duct (50 × 75 mm). Using magnetite suspensions, measurement through the whole depth of 50 mm is made with good accuracy. Velocity profiles are presented for solids concentrations of 5% and 9% solids by volume (20% and 36% by weight). Even at 9 vol% solids it is possible to reach a penetration depth of more than 25 mm.

  • 114.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Formation of hydrogen peroxide by chalcopyrite and pyrite2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by chalcopyrite (CuFeS2), which is a copper iron sulfide mineral, during grinding, was investigated. It was observed that chalcopyrite and pyrite generated H2O2 in pulp liquid during wet grinding and also the solids when placed in water immediately after dry grinding. The generation of H2O2 in either wet or dry grinding was thought to be due to a reaction between chalcopyrite and water where the mineral surface is catalytically active in producing •OH free radicals by breaking down the water molecule. When chalcopyrite and pyrite are mixed in different proportions, the formation of H2O2 was seen to increase with increasing pyrite fraction in the mixed composition. The results of H2O2 formation in pulp liquid of chalcopyrite and together with pyrite at different experimental conditions have been explained by Eh-pH diagrams of these minerals. This study highlights the necessity of revisiting the electrochemical and/or galvanic interaction mechanisms between the chalcopyrite and pyrite.

  • 115.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Formation of hydrogen peroxide by galena and its influence on flotation2014Ingår i: Advanced Powder Technology, ISSN 0921-8831, E-ISSN 1568-5527, Vol. 25, nr 2, s. 832-839Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, during the grinding of galena (PbS) was examined. It was observed that galena generated H2O2 in pulp liquid during wet grinding and also when the freshly ground solids were placed in water immediately after dry grinding. The generation of H2O2 during either wet or dry grinding was thought to be due to a reaction between galena and water, when the mineral surface is catalytically active, to produce OH• free radicals by breaking down the water molecule. It was also shown that galena could generate H2O2 in the presence or absence of dissolved oxygen in water. The concentration of H2O2 formed increased with decreasing pH. The effects of using mixtures of pyrite or chalcopyrite with galena were also investigated. In pyrite-galena mixture, the formation of H2O2 increased with an increase in the proportion of pyrite. This was also the case with an increase in the fraction of chalcopyrite in chalcopyrite-galena mixtures. The oxidation or dissolution of one specific mineral rather than the other in a mixture can be explained better by considering the extent of H2O2 formation rather than galvanic interactions. It appears that H2O2 plays a greater role in the oxidation of sulphides or in aiding the extensively reported galvanic interactions. This study highlights the necessity of further study of electrochemical and/or galvanic interaction mechanisms between pyrite and galena or chalcopyrite and galena in terms of their flotation behaviour.

  • 116.
    Javadi, Alireza
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Formation of hydrogen peroxide by sulphide minerals2014Ingår i: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 141, s. 82-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by sulphide minerals during grinding was investigated. It was found that pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite ((Zn,Fe)S), and galena (PbS), which are the most abundant sulphide minerals on Earth, generated H2O2 in pulp liquid during wet grinding in the presence of dissolved oxygen in water and also when the solids are placed in water immediately after dry grinding. Pyrite generated more H2O2 than other minerals and the order of H2O2 production by the minerals found to be pyrite > chalcopyrite > sphalerite > galena. The pH of water influenced the extent of hydrogen peroxide formation where higher amounts of H2O2 are produced at highly acidic pH. Furthermore, the effect of mixed sulphide minerals, i.e., pyrite–chalcopyrite, pyrite–galena, chalcopyrite–galena and sphalerite–pyrite, sphalerite–chalcopyrite and sphalerite–galena on the formation of H2O2 showed increasing H2O2 formation with increasing pyrite fraction in chalcopyrite–pyrite, galena–pyrite and sphalerite–pyrite compositions. The results also corroborate the amount of H2O2 production with the rest potential of the sulphide minerals; higher the rest potential of a sulphide mineral, formation of H2O2 is more. Most likely H2O2 is responsible for the oxidation of sulphide minerals and dissolution of non-ferrous metal sulphides in the presence of ferrous sulphide in addition to galvanic interactions. This study highlights the necessity of revisiting the electrochemical and/or galvanic interactions between pyrite and other sulphide minerals in terms of their flotation and leaching behaviour in the context of inevitable H2O2 existence in the pulp liquid.

  • 117.
    Lund, Cecilia
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Geometallurgy: A tool for better resource efficiency2014Ingår i: European Geologist Magazine, ISSN 1028-267X, nr 37, s. 39-43Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Higher environmental and socio-economic demands in the exploitation of the future mineral resources require comprehensive knowledge on ore bodies even in the early stages of the mining process. Geometallurgy combines geological and mineral processing information to create a spatial model for production planning and management. Applying a geometallurgical concept improves resource efficiency, reduces operational risks and helps in optimising production in such a way that sustainability and socio-economic factors also are considered. With a geometallurgical model it is possible to study different production scenario starting from exploration to the feasibility and production stages. There are some alternative ways for building a geometallurgical model but the mineralogical approach is generic and can be adopted to any kind of mineral resources. This paper describes how a concept like this has been used in the mining industry and demonstrates the benefits in terms of improved resource efficiency in different ore deposits.

  • 118.
    Mwanga, Abdul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Liberability: A new approach for measuring ore comminution behavior2014Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Crushability and grindability are traditionally used to describe the material properties in comminution. These parameters neglect the main objective of ore comminution, the mineral liberation and therefore information is incomplete. A new concept called liberability: the easiness of mineral liberation in comminution is introduced to fill the gap. Establishing a liberability map of a deposit requires grindability tests and liberation measurements for the grinding product. The liberability curve shows the degree of liberation of the mineral against grinding energy and offers better baseline for resource optimization than the grindability curve. A case study with a magnetite iron ore from Malmberget, northern Sweden, shows that certain shortcuts can be applied to keep the experimental effort reasonable which is important, particularly when applying the liberability in a geometallurgical program. In Malmberget the liberability is depending on the grade and grain size of magnetite. A significant difference between grindability and liberability can be observed.

  • 119.
    Minz, Friederike
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lasskogen, Jonas
    Boliden Mines, Exploration Department.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lithology and mineralisation types of the Rockliden Zn–Cu massive sulphide deposit, north-central Sweden: Implications for ore processing2014Ingår i: Transactions - Institution of Mining and Metallurgy. Section B. Applied earth science, ISSN 0371-7453, E-ISSN 1743-2758, Vol. 123, nr 1, s. 2-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Rockliden Zn–Cu volcanic-hosted massive sulphide deposit is located approximately 150 km south of the Skellefte ore district, north-central Sweden. Most of the mineralisation is found at the altered stratigraphic top of the felsic volcanic rocks, which are intercalated in the metamorphosed siliciclastic sedimentary rocks of the Bothnian Basin. Mafic dykes cross-cut all lithological units, including the massive sulphides, at the Rockliden deposit. The relatively high Sb grade of some parts of the mineralisation results in challenges in handling of the Cu–Pb concentrate in the smelting process. The aim of this study is to characterise different host rock units and ore types by their main mineralogy, as well as by their trace mineralogy with focus on the Sb-bearing minerals. Ore types are distinguished largely on the basis of their main base-metal bearing sulphide minerals, which are chalcopyrite and sphalerite. Several Sb-bearing minerals are documented and differences in the trace mineralogy between rock and ore types are highlighted. Based on the qualitative ore characterisation, rock- and ore-intrinsic parameters, such as the pyrite, pyrrhotite and magnetite content of the massive sulphides, the trace mineralogy and its association with base-metal sulphide minerals, are outlined and discussed in terms of relevance to the ore processing.

  • 120.
    Jonsén, Pär
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Häggblad, Hans-Åke
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Material- och solidmekanik.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Modelling of fluid, particle and structure interactions in a tumbling ball mill for grinding of minerals2014Konferensbidrag (Refereegranskat)
  • 121.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Rao, Hanumantha
    Bordes, Romain
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Holmberg, Krister
    Chalmers University of Technology, Chalmers University of Technology, Department of Chemical and Biological Engineering.
    Fredriksson, Andreas
    LKAB.
    Molecular recognition in mineral flotation: Selectivity in apatite-calcite system2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The present investigation aims to develop and distinguish mineral specific reagents with two functional groups for use in flotation of calcium containing minerals. For this purpose, a series of dicarboxylate-based surfactants with varying length between the carboxylate groups (one, two or three methylene groups) were synthesized. As reference, a surfactant with the same alkyl chain length but with only one carboxylate group in the polar part was synthesized. The adsorption behavior of these new reagents on pure apatite and calcite mineral surfaces was studied using Hallimond tube flotation, FTIR and ζ potential measurements. The relation between the adsorption behavior of a given surfactant on a specific mineral surface and its molecular structure over a range of concentration and pH values, as well as the region of maximum recovery were established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in flotation studies is substantiated by ζ potential and infra-red spectroscopy data.

  • 122.
    Rosenkranz, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sustainable Processing of Mineral Resources2014Ingår i: Society of Materials Engineering for Resources. International Journal, ISSN 1347-9725, Vol. 20, nr 1, s. 17-22Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reviews some of the recent challenges in the sustainable processing of primary mineral resources and discusses the technical prospects for meeting these challenges. The second part describes the integrated approach of geometallurgy being a prerequisite for improving resource efficiency along the production chain of minerals and metals. The different elements of a geometallurgical program are discussed and examples for ongoing geometallurgical research and education as pursued at Luleå University of Technology are presented.

  • 123.
    Lamberg, Pertti
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Systematic Diagnosis of Flotation Circuit Performance Based on Process Mineralogical Methods2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    Operators of industrial flotation circuits experience every now and then situations where the processing performance of the plant is poorer than expected. Usually this leads to a continual and useless debate whether the problems are related to the ore properties or to the process. This paper presents a systematic approach to problem diagnosis using an analysis method based on process mineralogical tools. The diagnosis first requires a base-case analysis where the key process streams of the circuit have been sampled and studied by applying mineral process simulation in combination with the particle tracking technique, i.e. by balancing mixed particles of different mineral composition. This creates the base model of the flotation process against which the deviations are compared. Common performance problems are divided in three groups, which refer to recovery, grade and impurity. The mineralogical reason can in each case be a change in (i) mineral assemblage, (ii) head grade, (iii) liberation degree, or (iv) mineral associations. The diagnosis progresses by classifying the indications and by ruling out causes by means of process mineralogical methods. The procedure is presented as a diagnosis chart with suggestions for how to cure the problem. To illustrate the application of the method several practical examples are presented.

  • 124.
    Mwanga, Abdul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Test Methods for Characterising Ore Comminution Behavior in Geometallurgy2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Comminution test methods used within mineral processing have mainly been developed for selecting the most appropriate comminution technology for a given ore, designing a grinding circuit as well as sizing the equipment needed. Existing test methods usually require comparatively large sample amounts and are time-consuming to conduct. This makes comprehensive testing of ore comminution behavior – as required in the geometallurgical context – quite expensive. Currently the main interest in the conduct of comminution test lies in the determination of particle size reduction and related energy consumption by grindability test methods, which provide the necessary information about mill throughput. In this procedure mineral liberation is regarded as a fixed parameter due to missing this information in ore characterization as well as a lack of suitable comminution models. However, ignoring the connection between particle size and mineral liberation prevents the scheduling and controlling of the production process from being optimal.For these reasons new comminution tests need to be developed or alternatively the existing test methods need to be suited to geometallurgical testing where the aim is to map the variation of processing properties of an entire ore body. The objective of this research work is on the one hand to develop small-scale comminution test methods that allow linking comminution behavior and liberation characteristics to mineralogical parameters, and on the other hand establish a modeling framework including mineral liberation information.Within the first stage of the study the comminution of drill cores from Malmberget’s magnetite ore, classified by modal mineralogy and texture information, have been investigated. It was found that there is a direct correlation between the mechanical strength of the rock, as received from unconfined compressive or point load tests, and the crusher reduction ratio as a measure for crushability. However, a negative correlation was found between crushability and grindability for the same samples. The grindability showed inverse correlation with both magnetite grade and the magnetite’s mineral grain size. The preliminary conclusion is that modal mineralogy and micro-texture (grain size) can be used to quantitatively describe the ore comminution behavior although the applied fracture mechanism of the mill cannot be excluded.With crushed ore samples from Malmberget also grindability tests and mineral liberation analyses were conducted using laboratory tumbling mills of different size. Starting from the dimensions of the Bond ball mill a modified test method was developed where small size samples of approximately 220 g were pre-crushed and ground in a down-scaled one-stage grindability test. Down-scaling was done by keeping similar impact effects between the mills. Mill speed and grinding time were used for adjusting the number of fracture events in order to receive similar particle size distributions and specific grinding energy when decreasing mill size by the factor 1.63. A detailed description of the novel geometallurgical comminution test (GCT) is given.With respect to ore crushability and autogenous and semiautogenous grinding (AG/SAG) also drop weight tests were conducted. For a more accurate and precise measurement of the energy transferred to the sample a novel instrumented drop weight was used. Initial tests with fractions of drill cores and pre-crushed ore particles showed that the simple energy calculation based on potential energy needs to be corrected. For the future work these tests will be extended to other ore types in order to investigate the effects of mineralogy and to include mineral liberation in comminution models suitable for geometallurgy.

  • 125.
    Stener, Jan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Carlson, Johan E.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Sand, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Towards the measurement of local particle mass fractions in magnetite suspensions2014Ingår i: 2014 IEEE International Ultrasonics Symposium, IUS 2014: Chicago, Ill, 3-6 September 2014, Piscataway, NJ: IEEE Communications Society, 2014, s. 939-942Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the mining industry, magnetite particles are transported in suspensions with water through different stages of the process. In some of these stages, it is of interest to monitor both the concentration and particle velocity over a cross-section of the flow. High particle concentration makes development of flow measurement techniques challenging. An additional challenge is that the flow is often accessible from one side only, which further limits the selection of applicable techniques. Previous work by the authors focused on using pulse-echo ultrasound for flow velocity profile estimation. In this paper the same setup is used to simultaneously study local variations in solids concentration. Ultrasound pulses are transmitted into the suspension, and the resulting backscatter is recorded. The statistics of the backscatter depend on solids concentration, particle size distribution, particle density, etc. We demonstrate how a short-time (windowed) Power Spectral Density (PSD) estimate can be used to obtain qualitative information about local solids concentration variations. For demonstration, a magnetite suspension carrying up to 7.5 vol% particles (29 wt%, mean particle size 34 μm) is pumped through a closed rectangular channel. When the pump is stopped, pulse-echo ultrasound (with a center frequency of 2.25 or 3.5 MHz) is used to monitor the sedimentation process. Nine snapshots of the process are included. These show a time lapse of the sedimentation, with 5 s between each image. It is clear that the short-time PSD is a good indicator of local mass fraction variations.

  • 126.
    Pålsson, Bertil
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Martinsson, Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wanhainen, Christina
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fredriksson, Andreas
    Mining Technology R and D, LKAB Kiruna Mine.
    Unlocking Rare Earth Elements from European apatite‐iron ores2014Ingår i: ERES 2014 - 1st International Conference on European Rare Earth Resources: Book of Proceedings / [ed] Efthymios Balomenos; Dimitrios Panias; Ioannis Paspaliaris, Santorini: Heliotopos Conferences Ltd. , 2014, s. 211-220Konferensbidrag (Refereegranskat)
    Abstract [en]

    Rare Earth Elements are known to occur within apatite‐magnetite ores of the Kiruna type. Previously it was assumed that the REE was associated to the apatite part of the ore. It is now shown that the REE follows the apatite to a much less degree, and that the REE are contained in the minerals monazite, allanite and some unknown REE‐phase still to be identified. Monazite occurs as inclusions in the apatite as well as free particles. Allanite is to some degree in mixed grains with magnetite but also in free particles. Monazite mainly reports to the apatite concentrate while allanite largely goes to the tailings. Laboratory flotation also shows some preferential concentration of heavy REE over light REE to the apatite concentrate. A new EU project, REEcover, will characterise the REE phases in this type of iron ore and among the different process streams within the mineral beneficiation chain.

  • 127.
    Parian, Mehdi
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lamberg, Pertti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rosenkranz, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Using modal composition instead of elemental grades in mineral resource estimate – high quality modal analysis by combining X-ray diffraction and X-ray fluorescence2014Konferensbidrag (Övrigt vetenskapligt)
  • 128.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Patra, Anuttam
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Bordes, Romain
    Chalmers University of Technology.
    Holmberg, Krister
    Chalmers University of Technology.
    Molecular recognition mechanisms in biomineralization applied to reagents selectivity in froth flotation2013Konferensbidrag (Övrigt vetenskapligt)
  • 129.
    Stener, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Project: Wet LlMS - Measurements and models2013Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 130.
    Lamberg, Pertti
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lund, Cecilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Taking Liberation Information into a Geometallurgical Model: Case Study Malmberget, Northern Sweden2012Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Geometallurgical model aims to capture geological and metallurgical variation of an ore in a 3D map. This is an important part of production planning and management. In creating such a model geological and metallurgical information is combined but current practices almost solely ignore the liberation information. This paper describes a technique how this important data can be taken into a geometallurgical model. Malmberget, the case study iron ore in Northern Sweden, consists of several ore lenses with variable mineralogy illustrated e.g. in magnetite-hematite ratio. Modal mineralogy does not fully explain the metallurgical response. To include ore texture and mineral liberation factors two sub-models were created based on liberation analyses of metallurgical testing and the Particle Tracking technique. Consequently, for each ore block, the particle breakage model gives the liberation distribution. Thereafter the process model, consisting of unit operations with property based models, forecasts the metallurgical response.

  • 131.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Activity: Minerals engineering education at LTU2011Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 132.
    Nurni, Viswanathan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Activity: Oxidation kinetics of Fe-Cr and Fe-V liquid alloys under controlled oxygen pressures2010Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 133.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Aktivitet: Konferens i mineralteknik 20092009Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 134.
    Tano, Kent T.
    et al.
    LKAB, Research and Development, SE-983 81 Malmberget.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Rannar, Stefan
    LKAB, Research and Development, SE-983 81 Malmberget.
    Alatalo, Johanna
    LKAB, Research and Development, SE-983 81 Malmberget.
    Feature Extraction of a Strain-Gauge Signal Using Wavelets for Monitoring of a Tumbling Mill2004Ingår i: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, Vol. 37, nr 15, s. 35-39Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Techniques that measure the force acting on a lifter bar, when it hits the charge inside a tumbling mill, have got an increased interest because of its direct physical relation to the behavior of the grinding charge. The possibility to combine it with discrete element modeling (DEM), which gives an opportunity to visualize the charge motion, opens new possibilities to understand the complex phenomena that takes place inside a grinding mill. In this work, a method for the measurement of the apparent filling level in a pilot ball mill, the Metso Continuous Charge Measurement system (CCM) has been used. The technique uses a strain gauge sensor, mounted on a flat steel spring, which is fitted into a recess underneath a lifter bar. Deflection of the lifter bar during every mill revolution will then give rise to a characteristic signal pattern depending on different operating conditions.

    In this work, which should be treated as an introduction, we show how the discrete wavelet transform can be used in multivariate calibration. It will be shown that by using the fast wavelet transform on individual signals as a pre-processing method in regression modeling on CCM measurements, good compression is achieved with almost no loss of information. The predictive ability and diagnostics of the data compressed regression model is almost the same as for the uncompressed.

  • 135. Johansson, Karin
    et al.
    Larsson, C.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Forsling, Willis
    Kota, Hanumantha Rao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Ronin, Vladimir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Reply to the discussion by Knut O. Kjellsen of the paper "Kinetics of the hydration reactions in the cement paste with mechanochemically modified cement: 29Si magic-angle-spinning NMR study"2000Ingår i: Cement and Concrete Research, ISSN 0008-8846, E-ISSN 1873-3948, Vol. 30, nr 8, s. 1325-1328Artikel i tidskrift (Refereegranskat)
  • 136.
    Lamberg, Pertti
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pertti, Hautala
    Pentti, Sotka
    Sari, Saavalainen
    Mineralogical balances by dissolution methodology1997Konferensbidrag (Övrigt vetenskapligt)
  • 137.
    Karlkvist, Tommy
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Bertil
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Synergism among collectors used for flotation of apatite and REE mineralsManuskript (preprint) (Övrigt vetenskapligt)
123 101 - 137 av 137
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