Minerals extraction and processing

The extraction, iincl sobsecniem processing, ol metallic anti non-metallic minerals are major application areas Tor the decanter. This classiMcation obviously overlaps considerably with the production of inorganic chemicals (covered in Section 3.9.1), and the treatment of calcium carbonate differs little, whether it be intended as a chemical or for other uses, 

Typical minerals involving the decanter in tlieir processing include calcium carbonate and chloride, clays, gypsum and potash slimes. 

A significant part of the wet extraction processes for minerals invedves either the removal of oversi/e materials from a suspension or the division of a suspension inlo two fractions by particle size. For these purposes, the decanter, operating in classiticatinn mode, is an ideal processing tool. 

Other minerals — metallic or non-metallic — are processed similarly, such as bentonite, chiilk, mica, and those minerals produced for use as pigments In paints. For these duties, the decanter should be able to operate at difl erent speeds, and have a variable speed back-drive. Full wear protection is essential. The use of ilocculants may be necessary for some mineral processing activities. 

A great deal of mineral processing ends with a concentrated slurry of the required product, and this is usually dewatered to a cohesive cake in a decanter, and may be washed as well, on the beach of a standard decanter, or in a screcn-bowl machine. 

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EPA (1984) estimated that about 0.2 Ci of thorium-230 is annually emitted into the air from uranium mill facilities, coal-fired utilities and industrial boilers, phosphate rock processing and wet- process fertilizer production facilities, and other mineral extraction and processing facilities. About 0.084 Ci of thorium-234 from uranium fuel cycle facilities and 0.0003 Ci of thorium-232 from underground uranium mines are emitted into the atmosphere annually (EPA 1984). 

These are produced, for example, during incomplete combustion processes, and mineral extraction and processing. They can be organic or inorganic, and can form aerosols in which hydrocarbons may be present (these hydrocarbons may have toxic effects). Examples include coal dust and asbestos. 

Minerals and Metals. HCl is consumed in many mining operations for ore treatment, extraction, separation, purification, and water treatment (see Mineral recovery and processing). Significant quantities are also used in the recovery ofmolybdenum (see Molybdenum and molybdenum alloys) and gold (see Gold and gold compounds). This market consumed about 36 thousand metric tons in 1993. 

See Liquid-solid Metallurgy, extractive Mineral recovery and processing. 

The treatments used to recover nickel from its sulfide and lateritic ores differ considerably because of the differing physical characteristics of the two ore types. The sulfide ores, in which the nickel, iron, and copper occur in a physical mixture as distinct minerals, are amenable to initial concentration by mechanical methods, eg, flotation (qv) and magnetic separation (see SEPARATION,MAGNETIC). The lateritic ores are not susceptible to these physical processes of beneficiation, and chemical means must be used to extract the nickel. The nickel concentration processes that have been developed are not as effective for the lateritic ores as for the sulfide ores (see also Metallurgy, extractive Minerals recovery and processing). 

Nonferrous Metal Production. Nonferrous metal production, which includes the leaching of copper and uranium ores with sulfuric acid, accounts for about 6% of U.S. sulfur consumption and probably about the same in other developed countries. In the case of copper, sulfuric acid is used for the extraction of the metal from deposits, mine dumps, and wastes, in which the copper contents are too low to justify concentration by conventional flotation techniques or the recovery of copper from ores containing copper carbonate and siUcate minerals that caimot be readily treated by flotation (qv) processes. The sulfuric acid required for copper leaching is usually the by-product acid produced by copper smelters (see Metallurgy, extractive Minerals RECOVERY AND PROCESSING). 

If a neutral chelate formed from a ligand such as acetylacetone is sufficiently soluble in water not to precipitate, it may stiH be extracted into an immiscible solvent and thus separated from the other constituents of the water phase. Metal recovery processes (see Mineral recovery and processing), such as from dilute leach dump Hquors, and analytical procedures are based on this phase-transfer process, as with precipitation. Solvent extraction theory and many separation systems have been reviewed (42). 

Pavel, S.K., Elvin, FJ., Extraction and Processing for the Treatment and Minimization of Wastes, Minerals, Metals, and Materials Society, Warrendale, PA (1994)... 

Acohols - [ALCOHOL FUELS] (Vol 1) - [FEEDSTOCKS-COALCHEMICALS] (Vol 10) - [DISTILLATION, AZEOTROPIC AND EXTRACTIVE] (Vol 8) - [COALCONVERSIONPROCESSES - LIQUEFACTION] (Vol 6) - [FLAME RETARD ANTS - PHOSPHORUS FLAME RETARD ANTS] (Vol 10) - [EXPLOSIVES AND PROPELLANTS - PROPELLANTS] (Vol 10) -as antifreeze [ANTIFREEZES AND DEICING FLUIDES] (Vol 3) -for automotive motor fuel [FUELS, SYNTHETIC - LIQUID FUELS] (Vol 12) -from castor oil [CASTOR OIL] (Vol 5) -in ceramic processing [CERAMICS - CERAMIC PROCESSING] (Vol 5) -from hydrocarbon oxidation [HYDROCARBON OXIDATION] (Vol 13) -as hypnotic and sedative [HYPNOTICS, SEDATIVES, ANTICONVULSANTS, AND ANXIOLYTICS] (Vol 13) -m metal polishes [POLISHES] (Vol 19) -from oxo process [OXO PROCESS] (Vol 17) -permanganate oxidation [MANGANESE COMPOUNDS] (Vol 15) -reactions with silanes [SILICON COMPOUNDS - SILANES] (Vol 22) -role m mineral processing [MINERALS RECOVERY AND PROCESSING] (Vol 16)... 

Ferrosilicon - [CARBON - CARBON AND ARTIFICIALGRAPHITE - APPLICATIONS OF BAKED AND GRAPHITIZED CARBON] (Vol 4) - [SILICON AND SILICON ALLOYS - CHEMICAL AND METALLURGICAL] (Vol21) - [METALLURGY - EXTRACTIVE METALLURGY] (Vol 16) - [MINERALS RECOVERY AND PROCESSING] (Vol 16) - [SILICON COMPOUNDS-SILANES] (Vol 22) -as calcium carbide impurity [CARBIDES - CALCIUM CARBIDE] (Vol 4)... 

A. Homung, W. Koch, J. Schoner, J. Furrer and H. Seifert, Stepwise pyrolysis of electronic scrap, TMS Fall 2002 Extraction and Processing Division Meeting on Recycling and Waste Treatment in Mineral and Metal Processing Technical and Economic Aspects, B. Bjorkman, C. Samuelsson, J. O. Wikstrom (Eds.), GTC-Print... 

R.J. de Klerk, G. P. Demopoulos, Continuous Circuit Production and Accelerated Ageing of Iron(III)-Arsenic(V) Coprecipitates - Probing Process-Stability Relationships , EPD Congress 2008 Proceedings of Sessions and Symposia Sponsored by the Extraction and Processing Division (EPD), ed. S.M. Howard, (Warrendale, PA The Minerals, Metals and Materials Society, 2008), 3-10... 

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