| 1. |
- Awe, Samuel Ayowole, et al.
(författare)
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Leaching mechanism of tetrahedrite in alkaline sulfide solution
- 2010
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Ingår i: Conference in Minerals Engineering. - : Luleå tekniska universitet. - 9789174390971 ; , s. 13-24
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The dissolution kinetics of tetrahedrite in aqueous alkaline sodium sulfide solutions was investigated in this present study. The effect of mineral particle size, reaction temperature, sodium sulfide and sodium hydroxide concentrations on the rate of dissolving antimony from tetrahedrite were studied. The result reveals that the rate of reaction increases with increasing reaction temperature, sodium sulfide concentration, sodium hydroxide concentration and with decreasing mineral particle size. The kinetics study indicates that tetrahedrite leaching rate by the lixiviant under the selected conditions is chemically controlled through the particle surface reaction. Therefore, the activation energy of antimony dissolution from tetrahedrite was estimated to be 81 kJ/ mol, which is in agreement with the value reported for the chemically controlled reactions process.
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| 2. |
- Ikumapayi, Fatai, et al.
(författare)
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Recycling of process water : effect of calcium and sulphate ions in sulphides flotation
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 51-61
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The effects of major components of calcium and sulphate ions in process water on sulphide mineral flotation has been investigated through Hallimond flotation of pure sulphide minerals using tapwater and water containing sulphate and calcium ions as well as through bench scale flotation of complex sulphide ores using tapwater and process water and with tapwater in the presence of calcium and sulphate ions. Hallimond flotation indicated activation of pyrite and slight depression of galena and chalcopyrite in the presence of high concentration of major species of calcium and sulphate ions using potassium amyl xanthate as collector. Bench scale flotation indicated activation of zinc when processwater was used and flotation in tapwater containing calcium and sulphate ions presented similar but not identical results.
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| 3. |
- Johansson, Björn, et al.
(författare)
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Flotation and leach tests performed within a geo-metallurgical project on gold in the Aitik Cu-Au-Ag-(Mo) deposit
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 73-84
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Laboratory flotation tests were done with all samples after 7 and 11 minutes of grinding. Tail products from the laboratory flotation tests were leached for Au using cyanide. Different ore types could be distinguished from their particle size distribution after grinding. Similar mineralogical structures could be tied to samples with a lower than expected Cu-recovery and mineralogical explanations for high and low Au recoveries are given in this paper.
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| 4. |
- Jonsén, Pär, et al.
(författare)
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Prediction of mill structure behaviour in a tumbling mill
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 85-98
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Computational demands and the lack of detailed experimental verification have limited the value of Distinct Element Method (DEM) modelling approaches in mill simulation studies. This paper presents the results of a study in which the deflection of a lifter bar in a pilot ball mill is measured by an embedded strain gauge sensor and compared to deflections predicted from finite element (FE) simulations. The flexible rubber lifter and the lining in a tumbling mill are modelled with the finite element method (FEM) and the grinding medium modelled with DEM. The deflection profile obtained from DEM-FE simulation shows a reasonably good correspondence to pilot mill measurements. To study the charge impact on the mill structure two different charges are used in the simulations. The approach presented here is a contribution to the validation of DEM-FE simulations and an introduction to the description of a bendable rubber lifter implemented in a DEM-FEM mill model. It opens up the possibility to predict contact forces for varying mill dimensions and liner combinations. FEM is especially valuable in this case, since there are readily available libraries with material models. This is a follow-up work to previous preliminary result from a mono-size ball charge interaction study.
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| 5. |
- Kota, Hanumantha Rao
(författare)
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Role of non-ionic surfactant in fatty acid phosphate gangue flotation from magnetite fines
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 169-183
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Adsorption, contact angle and flotation of anionic Atrac and non-ionic ethaloxylated nonylphenol surfactant, and their mixture on apatite and magnetite were studied. The effect of calcium ions and sodium silicate on Atrac adsorption was investigated. The effect of Atrac adsorption on the contact angle data of apatite and magnetite in the presence and absence of sodium silicate was also examined. Wettability of solids depends on solids surface free energy and the surface energies of apatite and magnetite powders were calculated from polar and non-polar liquid contact angle data.A decrease in particle size increased the polar contribution to surface free energy due to unsaturated broken bonds on the surface. Atrac is seen to adsorb equally on apatite and magnetite, and the adsorption increased in the presence of calcium ions. The presence of water glass decreased the Atrac contact angle data on magnetite and also the flotation response demonstrating its role as magnetite depressant in flotation. The presence of non-ionic surfactant enhanced the Atrac flotation of apatite with no flotation of magnetite. Bench-scale flotation tests showed that 50% of Atrac can be replaced with non-ionic collector without impairing the flotation results. Results also illustrate that the non-ionic adsorbs on apatite in equal amount of Atrac collector signifying 1:1 composition of anionic and non-ionic collector on apatite surface. Non-ionic head group sitting in between anionic head groups screens the electrostatic repulsion and forms compact adsorbed layer on apatite surface thereby increasing the hydrophobicity and flotation.
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| 6. |
- Pålsson, Bertil, et al.
(författare)
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Fine screening with electrically heated screen decks : report over initial tests and their evaluation
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 155-168
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Minelco by LKAB, Technology and Business Development, has commissioned Mineral Processing at LTU to conduct a series of investigations with a new screening device hitherto not used by LKAB. The screen, Mogensen Sizer G054 with electrically heated decks, was during the trials located in the pilot plant at Mineral Processing, where a test station was built for it. The purpose of the investigations was to test some specific applications, and to prepare a standard test procedure for evaluating screening tests with a Mogensen Sizer. One application was the production of magnetite -1 mm from sinter fines, where very strong consolidation effects were discovered and had to be taken into consideration. Specifically, consolidated sinter fines with moisture content more than 1 % gave high losses.The tests show that the best way to evaluate the screening results is to plot the proportion of finished product, and the loss of the correct fraction as a function of feed rate and moisture content. These being quantity results, they need to be supplemented with quality parameters, and the best seem to be the weight percentage of too coarse and too fine particles in the finished product. The direct effect of the level of heat is not yet clear. There appears to be some threshold level for the heating, but to what extent this is related to the screen deck type, the heat capacity and density of the material, or the particle size, is not known.
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| 7. |
- Rosenkranz, Jan
(författare)
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Mineral processing at Luleå University of Technology : meeting the research and educational needs
- 2010
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Ingår i: Conference in Minerals Engineering. - : Luleå tekniska universitet. - 9789174390971 ; , s. 1-12
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- With the start of the new decade the Mineral Processing chair at Luleå University of Technology has been newly appointed. The scientific redirection of the chair includes several of the important topic areas of advanced mineral processing. From process mineralogy via comminution and concentration processes to mathematical modelling and simulation of particulate processing systems, the mineral processing research at Luleå University of Technology is shaped by the interaction of material, process and equipment. This contribution deals with the positioning of the chair in research and education to meet the upcoming needs in a time where the secured supply with high quality commodities is essential
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| 8. |
- Sellgren, Anders
(författare)
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A note on depositional behaviour and conduit flow resistance of complex slurries
- 2010
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Ingår i: Conference in Minerals Engineering. - Luleå : Luleå tekniska universitet. - 9789174390971 ; , s. 185-196
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Slurries in mineral processing typically have average particles sizes of 20 to 100μm with maximum sizes of up to 500 to 1000μm. With solids volumetric concentrations varying from a few percent up to and over 40% the corresponding slurries are here termed complex because they cover an intermediate area between "non-settling" and "settling" types of mixtures. Depositional and flow resistance behaviours, some of which may be considered counter-intuitive, are discussed based on reported observations with heavy ore concentrates, tailings and sand slurries.
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