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Founded in 1990, [2] it is both the largest and oldest agricultural equipment maker in the country. [3] [4] Having initially only associated with the tea processing industry in Sylhet, [5] it later expanded to include the manufacture of general farming machinery, specialising in tillers, seeders and power threshers among others.
Ammonium thiosulfate (ammonium thiosulphate in British English) is an inorganic compound with the formula [NH 4] 2 S 2 O 3. It is white crystalline solid with ammonia odor, readily soluble in water , slightly soluble in acetone and insoluble in ethanol and diethyl ether .
Fixation is commonly achieved by treating the film or paper with a solution of thiosulfate salt. Popular salts are sodium thiosulfate—commonly called hypo—and ammonium thiosulfate—commonly used in modern rapid fixer formulae. [1] Fixation by thiosulfate involves these chemical reactions (X = halide, typically Br −): [2]
Bioleaching is the extraction or liberation of metals from their ores through the use of living organisms.Bioleaching is one of several applications within biohydrometallurgy and several methods are used to treat ores or concentrates containing copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, and cobalt.
Sodium thiosulfate and ammonium thiosulfate have been proposed as alternative lixiviants to cyanide for extraction of gold from ores [8] and printed circuit boards. [9] The complex [Au(S 2 O 3) 2] 3-is assumed to be the principal product in such extractions. Presently cyanide salts are used on a large scale for that purpose with obvious risks. [8]
Leaching is a process widely used in extractive metallurgy where ore is treated with chemicals to convert the valuable metals within the ore, into soluble salts while the impurity remains insoluble. These can then be washed out and processed to give the pure metal; the materials left over are commonly known as tailings .
Cyanide leaching "heap" at a gold mining operation near Elko, Nevada. On top of the large mounds of ore, are sprinklers dispensing a solution of cyanide. Gold extraction is the extraction of gold from dilute ores using a combination of chemical processes. Gold mining produces about 3600 tons annually, [1] and another 300 tons is produced from ...
Gold cyanidation (also known as the cyanide process or the MacArthur–Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore through conversion to a water-soluble coordination complex. It is the most commonly used leaching process for gold extraction. [1]