WEBJan 28, 2023 · The evolution process of land subsidence in the study area from 2000 to 2020 under the action of groundwater extraction and coal mining was obtained through numerical simulation. Results showed that coal mining was the main cause of land subsidence compared to groundwater extraction in the study area.
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WEBFeb 3, 2016 · Pillar extraction, (also referred to as retreat mining; pillar recovery; stooping; pillar robbing; and bord and pillar second workings) is the practice of forming a series of pillars and then partially or totally extracting some or all of the pillars, usually with mining operations retreating out of a panel. There are a number of basic pillar extraction .
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WEBCoal liquefaction. Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals. This process is often known as "Coal to X" or "Carbon to X", where X can be many different hydrocarbonbased products. However, the most common process chain is "Coal to Liquid Fuels" (CTL).
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WEBThere are two main methods for extracting energy fuels from the Earth: mining and drilling. Mining is used to extract solid fuels, such as coal and uranium. Drilling is used to extract gaseous or liquid fuels, such as natural gas and crude oil. Subsurface mining describes the process of extracting resources from deep underground, using tunnels ...
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WEBJan 4, 2023 · The main reason for this was the lower amount of the active metakaolin structure in coal gangue at 900 °C, which was not conducive to the geopolymerization process. View Show abstract
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WEBMar 1, 2017 · A new coal gangue(CG) activation additive was studied in this paper, carbide slag(CS) was used as an auxiliary agent on the extraction of Al2O3 from coal gangue activated by Na2CO3 through acid ...
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WEBOct 1, 2007 · After roasting stone coal at 850 °C for 3 h, vanadium in stone coal could be leached with NaOH solution, and the leaching degree of vanadium reached %. (2) By this technology, vanadium could be recovered from stone coal with recovery of % in the whole process, which was higher than the classical technology, and the purity of the ...
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WEBHighefficiency extraction of Al from coalseries kaolinite and its kinetics by calcination and pressure acid leaching has been studied in detail. Calcination process promoted a phase transform from crystal kaolinite to amorphous compounds. Subsequently, Al occurred in the compounds was efficiently extracted by pressure acid leaching. At optimal conditions, .
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WEBExtraction and refining. ... The primary product of the smelting process outlined above is a carbonsaturated ferroalloy containing 76 to 80 percent manganese, 12 to 15 percent iron, up to percent carbon, and up to percent silicon. ... To obtain a product of low carbon and silicon content, manganese ore, lime flux, and coal are fused in ...
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WEBAug 1, 2018 · The efficient utilization of aluminum and silicon resources simultaneously is expected to reach by the process of alumina extraction from coal fly ash via Na 2 CO 3 activationacid leaching method. The impurities in the system, CaO and Fe 2 O 3 especially, would affect the process.
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WEBJul 1, 1996 · By in situ analysis of supercritical extraction of coal, the present authors8 confirmed that the main role of tetralin in supercritical toluenetetralin extraction of coal is the stabilzation of radicals through hydrogen transfer from the tetralin: tetralin stabilizes free radicals of the pyrolysis products and in effect inhibits both ...
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WEBMar 25, 2018 · The process of Extracting Coal from the ground can be conducted via two methods: • Surface mining • Underground mining Both these techniques include different types of mining, but all f them use giant machines to remove coal from under the ground. ... The machines used for this type of coal extraction can excavate at depths of more than ...
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WEBMar 10, 2014 · A novel process for the coupling treatment of coal gangue and red mud is reported. Red mud containing % Al2O3, % SiO2, and % Na2O by weight was used as the blended ingredients of coal gangue for alumina extraction. Calcination of coal gangue with the addition of Na2CO3 at 850 °C could obtain more than 90% of Al2O3 .
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WEBMay 1, 2017 · Novel process of alumina extraction from coal fly ash by predesiliing—Na2CO3 activation—Acid leaching technique article{Guo2017NovelPO, title={Novel process of alumina extraction from coal fly ash by predesiliing—Na2CO3 activation—Acid leaching technique}, author={Yanxia Guo and Zesen Zhao and Qian .
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WEBJun 15, 2021 · 1. Introduction. Coal fly ash is a byproduct of coal combustion in thermal power plants, and it causes serious pollution of the surrounding soil, air, and water [1], [2].The latest global annual coal fly ash production is estimated to be 750 million tonnes [3].To alleviate the pressure of storing coal fly ash, the extraction of valuable elements, .
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WEBOur process for REE production from coal ash involves two main stages: a physical enrichment step and a chemical enrichment/extraction step. The process comprises several key steps, shown in Figure 1, including screening, flotation, magnetic separation, size separation, aqueous washing, nitric acid digestion, and solvent extraction.
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WEBJan 9, 2017 · Coalbed methane (CBM) was first extracted from coal mines as a safety measure to reduce the explosion hazard posed by methane gas in the mines. Today the methane is captured and used as a source of energy. Deeper coal formations might require hydraulic fracturing to release the natural gas. Tight Sands.
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WEBFeb 20, 2019 · The synergistic extraction process was simulated to acquire the parameters with treatment 130 t/h coal gasifiion wastewater. The removal efficiencies of phenols and treatment costs for the synergistic extraction process had been addressed.
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WEBMay 21, 2015 · The integrated extraction of coal and gas combines coal mining with gas capture. Taking into account the gas deposition and flow conditions in the Chinese coal basins, this paper describes the status of the theory and key technologies of this integrated extraction system, and presents its appliion and practice in the Shaqu, Z, .
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WEBJan 1, 2024 · An innovative GORA vanadium extraction process was proposed for the treatment of stone coal in Shaanxi. This process effectively improved the roasting and leaching indices of stone coal. Because the GORA process removed carbon and produced a porous honeycomb structure, the stone coal was resistant to hightemperature .
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WEBFeb 1, 2024 · The gas migration provides a "material basis" for the gas extraction from the fractured zone of the goaf. The pressurerelief gas from the layer adjacent to the coal seam, as well as the residual gas from the mining process, flow through fracture channels and accumulate in the goaf, creating an area of gas enrichment.
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WEBJan 1, 2024 · The main carbon skeleton and the ash of the coal were the insoluble part during the extraction process, which was the UC. Download : Download highres image (403KB) Download : Download fullsize image; Fig. 10. Schematic diagram of aromaticrich low rank coal extraction process. Download : Download highres image (373KB)
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WEBPublished online: 01 Aug 2018. stone coal is directly carried out by metallurgical processes. Salt process, acid process and. alkali process three types of stone coal leaching including nine ...
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WEBJan 4, 2023 · To reveal how CaF2 improves the dissolution ratios of aluminum and iron ions in coal gangue, CaF2 and hydrochloric acid are used to extract Al3+ and Fe3+ from the coal gangue calcined powder. The leaching ratios of Al3+ and Fe3+ are measured, and the filter residues are analyzed by BET, XRD, and SEM. The results show that adding 3% .
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WEBFeb 14, 2016 · The various methods of mining a coal seam can be classified under two headings, surface. mining and underground mining. 2. 3. Methods of extraction. The most economical method of coal ex traction ...
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WEBJun 5, 2021 · 1. Introduction. Vanadium (V)bearing shale is a unique and abundant V resource in China, with an estimated reserve of approximately 62 billion tons [11], [25], [28].With the increasing demand for Vcontaining products, especially the implementation of China's new rebar standards, and the continuous development of the V redox flow .
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WEBSep 1, 2019 · It is difficult to utilize stone coal with a vanadium grade of below %. With the aim of effectively utilizing the silicon and vanadium in stone coal, the vanadium concentration and silicon extraction processes by alkaline leaching under reducing conditions were investigated. The effect of NaOH mass fraction, temperature and the .
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WEBMar 23, 2018 · Mining coal is a lot like mining any other metal or ore, it's just processed differently. Oil extraction is much different because oil is a liquid, not a solid like coal. There are many different ways of extracting it because oil is found in very diverse forms such as shale, liquid oil deposits, etc. ... which they extract, and then process by ...
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WEBFeb 15, 2020 · However, when coal bed is oxidized and heated up to 80 °C, compound disasters of CBM and coal spontaneous combustion tend to occur, which severely threatens the safety of CBM extraction. Therefore, the study on the coaloxygen reaction process of selfigniting coal in CBM wind flow at 80 °C is essential for improving CBM .
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WEBJan 25, 2018 · Coal also serves as fuel in the extraction of iron from iron ore and for the production of cement. Due to a rise in demand for coal, many mining techniques have evolved to extract the fossil fuel. A largescale mining of coal requires the use of draglines, trucks, conveyors, hydraulic jacks and shearers. ... This process is referred to as out ...
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WEBOct 1, 2016 · In our laboratory, a new process of alumina extraction from highalumina fly ash with a NH 4 HSO 4 + H 2 SO 4 mixed solution had been proposed. As shown in Fig. 1, the steps in this procedure include pressure leaching, filtration and washing, cooling crystallization and filtration, and this process, the leaching was enhanced by .
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WEBJun 6, 2022 · Lithium extraction from the coal gangue was systematically investigated via the integrated process of roasting and acid leaching with the mechanism analysis. The majority (94%) of lithium was extracted when raw samples are roasted at 400°C for 20 min before 4 h leaching with 2 mol/L hydrochloric acid at 60°C, which represented the .
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WEBApr 8, 2014 · The lowgrade vanadiumcontaining stone coal used in this experiment was collected from Wuxi Country, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through optimizing the process conditions of an effective and environmentallyfriendly technology, named calcified roastingsulfuric acid .
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