Physical separation processes are best understood in terms of the behaviour of individual ore particles.Yet,while different empirical particle-based separation modelling approaches have been developed,their predictive...Physical separation processes are best understood in terms of the behaviour of individual ore particles.Yet,while different empirical particle-based separation modelling approaches have been developed,their predictive performance has never been tested under variable process conditions.Here,we investigated the predictive performance of a state-of-the-art particle-based separation model under variable feed composition for a laboratory-scale magnetic separation of a skarn ore.Two scenarios were investigated:one in which the mass flow of the different processing streams could be measured and one in which it had to be estimated from data.In both scenarios,the predictive models were sufficiently general to predict the process outcomes of new samples of variable composition.Nevertheless,the scenario in which mass flow could be measured was4%more precise in predicting mass balances.The process behaviour of minerals present at concentrations above 0.1%by weight could be accurately predicted.Our findings indicate the potential use of this method to minimize the costs of metallurgical testwork while providing in-depth understanding of the recovery behaviour of individual ore particles.Moreover,the method may be used to establish powerful tools to forecast mineral recoveries for partly new ore types at a running mining operation.展开更多
The capabilities and opportunities of the application of automated mineralogy for the characterization of lithium-bearing zinnwaldite-micas are critically assessed. Samples of a crushed greisen-type ore comprising mos...The capabilities and opportunities of the application of automated mineralogy for the characterization of lithium-bearing zinnwaldite-micas are critically assessed. Samples of a crushed greisen-type ore comprising mostly of quartz, topaz and zinnwaldite (Li-rich mica) were exposed to further comminution by cone crusher and high voltage pulse power fragmentation. Product properties were analyzed by using a Mineral Liberation Analyser (MLA) and the obtained mineralogical and mineral processing relevant parameters were carefully evaluated with special focus on the characteristics of zinnwaldite. The results illustrate that both samples contain a significant quantity of very fine particles that are products of comminution. The modal mineralogy in the different sieve fractions is characterized by the accumulation of minerals of low hardness in the finest fraction and the enrichment of topaz, having a high hardness, in the somewhat larger fractions. Based on the results of mineral association data for zinnwaldite, a displacement of the muscovite-quartz ratio, in comparison to the results of modal mineralogy, was observed by indicating good quartz-zinnwaldite boundary breakage and weak muscovite-zinnwaldite breakage. Liberation as well as mineral grade recovery curves indicate that fraction 1000 to +500 μm is most suitable for beneficiation. The results of this study demonstrate that SEM-based image analysis, such as MLA, can effectively be used to investigate and evaluate phyllosilicate minerals in a fast and precise way. It is shown that the results of MLA investigations, such as modal mineralogy, are in good agreement with other analytical methods such as quantitative X-ray powder diffraction.展开更多
Solid organic matter is an important constituent not only in coal, but also in black shale-hosted ore deposits. The reliable recognition and quantification of organic carbon—as well as its microfabric relation to ass...Solid organic matter is an important constituent not only in coal, but also in black shale-hosted ore deposits. The reliable recognition and quantification of organic carbon—as well as its microfabric relation to associated inorganic minerals—plays a crucial role in characterization by scanning electron microscopy-based image analysis. However, the use of conventional epoxy resin in the preparation of grain mounts does not allow for recognition of solid organic carbon compounds. In this study we illustrate that the use of iodized epoxy resin readily overcomes this bottleneck. Best results are obtained with an addition of 15 wt% iodoform to the epoxy resin. With process samples of black shale-hosted polymetallic Kupferschiefer-type ore as a case study, it is shown that recognition and quantification of solid organic carbon are easily achieved and that tangible parameters such as particle and grain sizes, association and liberation for ore and gangue minerals can be determined in the presence of solid organic matter. Due to the inherent uncertainty of the exact chemical composition of the kerogen contained in Kupferschiefer, it was not possible to attain exact comparability between chemical Corg assays and assays calculated from MLA data. However, the results are still found to closely agree with one another. The strength of iodized resin lies in its ability to distinguish organic matter with high hydration ratios in addition to the easy integration in sample preparation. It could therefore be an attractive supplement in the analyses of other raw materials containing complex organic-matter.展开更多
基金the German Federal Ministry for Education and Research (BMBF) for funding the projects MoCa (grant number 033R189B) and AFK (grant number 033R128), which were essential to this studythe Saxore Bergbau GmbH for providing the samples for this studySabine Gilbricht (TU Bergakademie Freiberg) for support during SEM-MLA data acquisition
文摘Physical separation processes are best understood in terms of the behaviour of individual ore particles.Yet,while different empirical particle-based separation modelling approaches have been developed,their predictive performance has never been tested under variable process conditions.Here,we investigated the predictive performance of a state-of-the-art particle-based separation model under variable feed composition for a laboratory-scale magnetic separation of a skarn ore.Two scenarios were investigated:one in which the mass flow of the different processing streams could be measured and one in which it had to be estimated from data.In both scenarios,the predictive models were sufficiently general to predict the process outcomes of new samples of variable composition.Nevertheless,the scenario in which mass flow could be measured was4%more precise in predicting mass balances.The process behaviour of minerals present at concentrations above 0.1%by weight could be accurately predicted.Our findings indicate the potential use of this method to minimize the costs of metallurgical testwork while providing in-depth understanding of the recovery behaviour of individual ore particles.Moreover,the method may be used to establish powerful tools to forecast mineral recoveries for partly new ore types at a running mining operation.
文摘The capabilities and opportunities of the application of automated mineralogy for the characterization of lithium-bearing zinnwaldite-micas are critically assessed. Samples of a crushed greisen-type ore comprising mostly of quartz, topaz and zinnwaldite (Li-rich mica) were exposed to further comminution by cone crusher and high voltage pulse power fragmentation. Product properties were analyzed by using a Mineral Liberation Analyser (MLA) and the obtained mineralogical and mineral processing relevant parameters were carefully evaluated with special focus on the characteristics of zinnwaldite. The results illustrate that both samples contain a significant quantity of very fine particles that are products of comminution. The modal mineralogy in the different sieve fractions is characterized by the accumulation of minerals of low hardness in the finest fraction and the enrichment of topaz, having a high hardness, in the somewhat larger fractions. Based on the results of mineral association data for zinnwaldite, a displacement of the muscovite-quartz ratio, in comparison to the results of modal mineralogy, was observed by indicating good quartz-zinnwaldite boundary breakage and weak muscovite-zinnwaldite breakage. Liberation as well as mineral grade recovery curves indicate that fraction 1000 to +500 μm is most suitable for beneficiation. The results of this study demonstrate that SEM-based image analysis, such as MLA, can effectively be used to investigate and evaluate phyllosilicate minerals in a fast and precise way. It is shown that the results of MLA investigations, such as modal mineralogy, are in good agreement with other analytical methods such as quantitative X-ray powder diffraction.
文摘Solid organic matter is an important constituent not only in coal, but also in black shale-hosted ore deposits. The reliable recognition and quantification of organic carbon—as well as its microfabric relation to associated inorganic minerals—plays a crucial role in characterization by scanning electron microscopy-based image analysis. However, the use of conventional epoxy resin in the preparation of grain mounts does not allow for recognition of solid organic carbon compounds. In this study we illustrate that the use of iodized epoxy resin readily overcomes this bottleneck. Best results are obtained with an addition of 15 wt% iodoform to the epoxy resin. With process samples of black shale-hosted polymetallic Kupferschiefer-type ore as a case study, it is shown that recognition and quantification of solid organic carbon are easily achieved and that tangible parameters such as particle and grain sizes, association and liberation for ore and gangue minerals can be determined in the presence of solid organic matter. Due to the inherent uncertainty of the exact chemical composition of the kerogen contained in Kupferschiefer, it was not possible to attain exact comparability between chemical Corg assays and assays calculated from MLA data. However, the results are still found to closely agree with one another. The strength of iodized resin lies in its ability to distinguish organic matter with high hydration ratios in addition to the easy integration in sample preparation. It could therefore be an attractive supplement in the analyses of other raw materials containing complex organic-matter.
