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Acid Mine Drainage Formation, Dissemination and Control: Mining and Hydrological Perspectives
Published in Geoffrey S. Simate, Sehliselo Ndlovu, Acid Mine Drainage, 2021
Mineral processing entails the use of comminution circuits for mechanical size reduction using grinding and milling to increase surface area for subsequent mineral extraction in some cases (e.g., gold extraction) and/or to meet specifications for certain applications in other cases (e.g., coal) (Giblett and Morrell, 2016; Habib et al., 2020; Martínez et al., 2020). Three processes are critical in the context of AMD: (1) size reduction may generate sulphidic solid wastes in the form of waste rock or dust, (2) the use of strong extracting solutions in metallurgical processing generates sulphidic mine tailings and wastewaters laden with fine particles and colloids, and (3) strong extracting solutions such as peroxides and acids may promote weathering and AMD formation. Fine particles and colloids are also prone to both wind and water erosion.
Magnetic Separation
Published in Ko Higashitani, Hisao Makino, Shuji Matsusaka, Powder Technology Handbook, 2019
Many kinds of forces are used to separate or filter materials of different quality and size. Mineral processing especially includes the separation of solids, recovery of valuable solids from waste materials, and water or air purification. Materials have electric and magnetic properties; therefore, electromagnetic fields are employed to separate solids with different electric and magnetic properties. Consequently, for efficient separation it is important to increase the electromagnetic forces and decrease the interaction forces between different solid particles. Here various magnetic separation methods and unit operations to separate particles by virtue of differences in their magnetic properties are described.
Converting Minerals to Metals
Published in Karlheinz Spitz, John Trudinger, Mining and the Environment, 2019
Karlheinz Spitz, John Trudinger
Mineral processing or extractive metallurgy includes all activities and processes required to extract valuable minerals from their ores to produce pure metals. Metals are rarely found in their native metal form, gold being a notable exception. Most other metals exist as oxide, sulphide or silicate minerals, and these must be reduced to extract metals. Mineral processing plants usually combine a number of methods to extract and to purify metals.
Exploratory investigation on the use of low-cost alternative media for ultrafine grinding of coal
Published in International Journal of Coal Preparation and Utilization, 2022
Qingqing Huang, Aaron Noble, Deniz Talan
Comminution is one of the most critical unit operations in mineral processing and coal preparation, as size reduction is often needed to achieve liberation prior to concentration (King 1994; Valery and Jankovic 2002). While many modern coal preparation flowsheets do not directly employ fine grinding (Noble and Luttrell 2015), several state-of-the-art technologies seek to utilize extremely high purity coal in high value carbon products and other value-added end uses. This high purity coal product often requires extremely fine grinding to achieve the liberation needed for efficient separation. For example, ARQ has recently developed a process whereby a 99% pure hydrocarbon is produced from a coal refuse after grinding to a 3 micron mean size. The high purity carbon product is then sold as an oil fuel additive for marine or other markets (Snaith and Unsworth 2017). In another example, ultrafine pure carbon is commonly used for the synthesis and production of various carbon nanotubes and nanomaterials (Moothi et al. 2012; Qiu et al. 2004, 2002). Lastly, Huang et al. (2018) has shown that ultrafine grinding can release rare earth minerals from coal refuse permitting subsequent concentration and recovery.
Investigation of Particles Breakage and Weakening Behaviors in Multi-Component Feed Grinding by High Pressure Grinding Rolls (HPGR)
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Alireza Aminalroaya, Parviz Pourghahramani
Comminution is the first stage of mineral processing, and usually, the feed of comminution equipment is a mixture of different minerals with different breakage properties. Therefore, a deep understanding of each mineral’s breakage behavior and its effect on other minerals’ breakage behavior is crucial toward efficient grinding performance. High Pressure Grinding Rolls (HPGR) is grinding equipment designed for the breakage of particles based on an interparticle breakage mechanism (Schönert 1988). HPGR is used in the third or fourth stage of crushing or in the iron ore processing plant’s final stage to increase Blaine specific surface area (Abazarpoor et al. 2018; Meyer et al. 2016; Van der Meer and Gruendken 2010). The specific surface area of iron particles has a great effect on the production of pellets (Graça et al. 2015).
Influence of magnetized water on molybdenite flotation and its mechanism
Published in Environmental Technology, 2022
Zhen Wang, Tingshu He, Hui Li, Yubin Wang
Magnetized technology has been widely used in the fields such as the anti-scaling of boilers, anticorrosion of machined emulsion, reinforcement of concrete, increase in aquaculture production and synergy of mineral processing [1–3] Ehsan et al. [4]. In the field of mineral processing, besides the magnetized separation method used in selecting magnetized minerals, magnetic technology is also used as an auxiliary method for gravity, flotation and other mineral processing methods. Magnetized technology in the application of flotation research includes magnetization of flotation water, pulp or flotation reagents [1]. Evidence suggests that that the magnetized treatment can not only change the nature of water and flotation reagents but also can improve the efficiency of flotation [5,17–20]. The properties of magnetized water were analysed by Yao et al., the results showed that the pH value increased, conductivity and viscosity decreased when the water was magnetized. Zhu et al. studied the changing relationship between flotability of quartz and pH value with magnetized water and its mechanism, the results showed that the magnetized treatment can reduce the quartz flotability and Ca2+ activated ability of quartz [6].