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| 2. |
- Månbro, Carolina, 1982-, et al.
(författare)
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Chemical and Mineralogical Characterisation of Iron Ore Drillcore using µ-XRF
- 2023
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Ingår i: Proceedings Digital Conference i Minerals Engineering, 7-8 February, 2023, Luleå, Sweden. - : Luleå University of Technology. ; , s. 159-174
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Traditionally, geochemical assays have been used in geometallurgical programs to determine grade and recovery of the ore. The efficiency of this approach is questionable, since assays i) provide bulk geochemistry without providing host mineralogy for the element(s) of interest, and ii) are performed on small samples. Thus, ore mineral grade might be lower than the assays imply, due to the inclusion of elements of interest in the gangue mineralogy. Also, the samples analysed might not be representative on a deposit size scale due to their small volume. In μ-XRF, areas analysed are on a dm scale, providing a larger, and therefore more representable, analysis than e.g. a scanning electron microscope (SEM), yet providing a resolution comparable to SEM analyses. Another advantage of the μ-XRF is the possibility to detect elements as light as sodium, while simultaneously detecting heavy elements, e.g. REEs.Here, cut drillcore samples were scanned by μ-XRF at varying resolutions. The μ-XRF data was utilised for i) comparison with chemical assays, ii) identification of sample mineralogy, iii) comparison with mineralogy from X-ray diffraction (XRD), and iv) analysis of ore texture. The results show that regardless of the resolution used, the μ-XRF analyses correlate well with the results from geochemical assays, whereas for textural features a finer resolution yielded a more detailed picture, as was expected. The drillcore mineralogy compares well with the phases identified by XRD. However, mineral identification from μ-XRF is based on elemental spectrums. Therefore, polymorphs cannot be successfully discriminated and an insight into the deposit mineralogy, is needed for a correct mineral classification in these cases.
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| 3. |
- Chelgani, Saeed Chehreh, et al.
(författare)
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A comparative study on the effects of dry and wet grinding on mineral flotation separation : a review
- 2019
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854. ; 8:5, s. 5004-5011
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Forskningsöversikt (refereegranskat)abstract
- Water scarcity dictates to limit the use of water in ore processing plants particularly in arid regions. Since wet grinding is the most common method for particle size reduction and mineral liberation, there is a lack of understanding about the effects of dry grinding on downstream separation processes such as flotation. This manuscript compiles various effects of dry grinding on flotation and compares them with wet grinding. Dry grinding consumes higher energy and produces wider particle size distributions compared with wet grinding. It significantly decreases the rate of media consumption and liner wear; thus, the contamination of pulp for flotation separation is lower after dry grinding. Surface roughness, particle agglomeration, and surface oxidation are higher in dry grinding than wet grinding, which all these effects on the flotation process. Moreover, dry ground samples in the pulp phase correlate with higher Eh and dissolved oxygen concentration. Therefore, dry grinding can alter the floatability of minerals. This review thoroughly assesses various approaches for flotation separation of different minerals, which have been drily ground, and provides perspectives for further future investigations.
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| 4. |
- Guntoro, Pratama Istiadi, 1993-, et al.
(författare)
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Development and experimental validation of a texture-based 3D liberation model
- 2021
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Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 164
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Tidskriftsartikel (refereegranskat)abstract
- Prediction of mineral liberation is one of the key steps in establishing a link between ore texture and its processing behavior. With the rapid development of X-ray Microcomputed Tomography (µCT), the extension of liberation modeling into 3D realms becomes possible. Liberation modeling allows for the generation of particle population from 3D texture data in a completely non-destructive manner. This study presents a novel texture-based 3D liberation model that is capable of predicting liberation from 3D drill core image acquired by µCT. The model takes preferential, phase-boundary, and random breakage into account with differing relative contributions to the liberation depending on the ore texture itself. The model was calibrated using experimental liberation data measured in 3D µCT. After calibration, the liberation model was found to be capable of explaining on average of around 84% of the variance in the experimental liberation data. The generated particle population can be used for particle-based process simulation to evaluate the process responses of various ore textures subjected to various modes of breakage.
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| 5. |
- Isaksson, Jenny, et al.
(författare)
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Improved Settling Properties of Iron Silicate Slag by CaO Modifications
- 2023
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One of the most significant sources of copper losses from pyrometallurgical copper extraction is attributed to dissolved and entrained copper in the discarded slag. The entrained copper can be recovered via pyrometallurgical slag cleaning in a settling furnace. Reduced copper losses mean increased smelter profits by improved raw material efficiency, and, in addition, the slag will become a more environmentally safe by-product. One way to increase the copper recovery during the settling process is to modify the slag to improve the properties that decrease copper solubility and slag viscosity. In this study, iron silicate slag was modified using CaCO3 on an industrial scale to evaluate its effect on the settling process. More specifically, the changes in settling were related to the modifications and measurements of slag viscosity and copper droplet size distributions in the slag. The trial was evaluated by comparing the copper content in different batches, the size distribution of copper-containing droplets using automated scanning electron microscopy, and performing rheological studies using a high-temperature rheometer. The results showed that increasing the CaO content of the slag by modification with CaCO3 has a positive effect on the settling process and is thus a possible method to improve the industrial settling process of valuable metals in slag.
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| 6. |
- Larsson, Simon, et al.
(författare)
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A novel approach for modelling of physical interactions between slurry, grinding media and mill structure in wet stirred media mills
- 2020
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Ingår i: Minerals Engineering. - : Elsevier. - 0892-6875 .- 1872-9444. ; 148
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Tidskriftsartikel (refereegranskat)abstract
- Wet comminution is an important process in the mineral processing industry. Modelling of wet comminution in stirred media mills requires the simultaneous modelling of grinding media, a moving internal stirrer, and slurry. In the present study, a novel approach for modelling the physical interactions between slurry, grinding media and mill structure in a stirred media mill is presented. The slurry is modelled with the particle finite element method (PFEM). The grinding media is modelled using the discrete element method (DEM) and the mill structure is modelled using the finite element method (FEM). The interactions between slurry, grinding media and mill structure are modelled by two-way couplings between the PFEM, the DEM and the FEM models. The coupled model of the present study is used to predict the motion of slurry and grinding media, and to calculate the power draw during wet comminution in a pilot scale horizontal stirred media mill. Furthermore, the model is used to compare a Newtonian and a non-Newtonian model of the slurry, where the non-Newtonian model is used to capture experimentally observed shear-thinning. The coupled PFEM-DEM-FEM model preserves the robustness and efficiency of each of the methods and it gives the possibility to use large time increments for the fluid, greatly reducing the computational expense. The coupled model of the present work provide information on the complex dynamics of slurry and grinding media. The numerical model is shown to be a useful tool for increasing the knowledge and understanding of wet comminution in stirred media mills.
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| 7. |
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| 8. |
- Larsson, Simon, et al.
(författare)
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Preliminary validation of a stirred media mill model
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Wet fine grinding is an important process in the minerals industry. Modelling of wet grinding in stirred media mills is challenging since it requires the simultaneous modelling of grinding media consisting of a huge number of small grinding bodies, moving internal stirrer, and the pulp fluid. All of them in interaction with each other. In the present study, wet grinding in a stirred media mill is studied using coupled incompressible computational fluid dynamics (ICFD) and discrete element method (DEM) and finite element method (FEM) simulations. The DEM is used to model the grinding media, and the pulp fluid flow is modelled using the ICFD. Moreover, the FEM is used to model the structure of the mill body and is in combination with DEM used to estimate the wear rate in the system. The present implementation of the coupled ICFD-DEM-FEM preserves the robustness and efficiency of both methods, and it gives the possibility to use large time steps for the fluid with very low computation times.
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| 9. |
- Parian, Mehdi, 1982-
(författare)
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Development of a geometallurgical framework for iron ores - A mineralogical approach to particle-based modeling
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The demands for efficient utilization of ore bodies and proper risk management in the mining industry have resulted in a new cross-disciplinary subject called geometallurgy. Geometallurgy connects geological, mineral processing and subsequent downstream processing information together to provide a comprehensive model to be used in production planning and management. A geometallurgical program is an industrial application of geometallurgy. Various approaches that are employed in geometallurgical programs include the traditional way, which uses chemical elements, the proxy method, which applies small-scale tests, and the mineralogical approach using mineralogy or the combination of those. The mineralogical approach provides the most comprehensive and versatile way to treat geometallurgical data. Therefore it was selected as a basis for this study.For the mineralogical approach, quantitative mineralogical information is needed both for the deposit and the process. The geological model must describe the minerals present, give their chemical composition, report their mass proportions (modal composition) in the ore body and describe the ore texture. The process model must be capable of using mineralogical information provided by the geological model to forecast the metallurgical performance of different geological volumes and periods. A literature survey showed that areas, where more development is needed for using the mineralogical approach, are: 1) quick and inexpensive techniques for reliable modal analysis of the ore samples; 2) ore textural characterization of the ore to forecast the liberation distribution of the ore when crushed and ground; 3) unit operation models based on particle properties (at mineral liberation level) and 4) a system capable of handling all this information and transferring it to production model. This study focuses on developing tools in these areas.A number of methods for obtaining mineral grades were evaluated with a focus on geometallurgical applicability, precision, and trueness. A new technique developed called combined method uses both quantitative X-ray powder diffraction with Rietveld refinement and the Element-to-Mineral Conversion method. The method not only delivers the required turnover for geometallurgy but also overcomes the shortcomings if X-ray powder diffraction or Element-to-Mineral Conversion were used alone.Characterization of ore texture before and after breakage provides valuable insights about the fracture pattern in comminution, the population of particles for specific ore texture and their relation to parent ore texture. In the context of the mineralogical approach to geometallurgy, predicting the particle population from ore texture is a critical step to establish an interface between geology and mineral processing. A new method called Association Indicator Matrix developed to assess breakage pattern of ore texture and analyze mineral association. The results of ore texture and particle analysis were used to generate particle population from ore texture by applying particle size distribution and breakage frequencies. The outcome matches well with experimental data specifically for magnetite ore texture.In geometallurgy, process models can be classified based on in which level the ore, i.e. the feed stream to the processing plant and each unit operation, is defined and what information subsequent streams carry. The most comprehensive level of mineral processing models is the particle-based one which includes practically all necessary information on streams for modeling unit operations. Within this study, a particle-based unit operation model was built for wet low-intensity magnetic separation, and existing size classification and grinding models were evaluated to be used in particle level. A property-based model of magnetic beneficiation plant was created based on one of the LKAB operating plants in mineral and particle level and the results were compared. Two different feeds to the plant were used. The results revealed that in the particle level, the process model is more sensitive to changes in feed property than any other levels. Particle level is more capable for process optimization for different geometallurgical domains.
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| 10. |
- Parian, Mehdi, 1982-, et al.
(författare)
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Ore texture breakage characterization and fragmentation into multiphase particles
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The ore texture and the progeny particles after a breakage in the comminution are the missing link between geology and mineral processing in the concept of geometallurgy. A new method called association indicator matrix based on co-occurrence matrix was introduced to analyze the mineral association of ore texture and particles. The association indicator matrix can be used as a criterion to classify ore texture and analyze breakage behavior of ore texture. Within the study, the outcome of breakage analysis with association indicator matrix was used to generate particle population of iron ore texture after crushing. The particle size of forecasted particles was taken from experimental and frequency of breakage in phases was defined based on association indicator and liberation of minerals. Comparison of liberation distribution of iron oxide minerals from experimental and forecasted population shows a good agreement.
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