Gold cyanide process

Previous to the introduction of the gold-cyaniding process almost all the cyanide manufactured was made from sodium or potassium ferrocyanide, which was produced from animal matter, such as dried blood, horns, hoofs, and the residues of slaughter houses (see under Ferrocyanides, p. 79). 

Use Dyeing of textiles, waterproofing, varnishes, lead driers, chrome pigments, gold cyanidation process, insecticide, antifouling paints, analytical reagent, hair dye. 

The chlorination process, introduced in Europe in 1843, roasted ore with chlorides, followed by a hot brine leach and subsequent precipitation of the silver on copper. In 1887 it was discovered that gold and silver can be recovered by sodium cyanide, and this process displaced the dangerous chlorination process. By 1907 the cyanide process, where a cyanide solution is mixed with 2inc dust to precipitate the silver, was universally in use. 

Merrill-Crowe An improvement on the cyanide process for extracting gold from rock. The solution of gold cyanide is reduced with zinc dust, thereby precipitating the gold as a fine powder which is filtered off and smelted. Operated in South Africa. 

PAL [peroxide assisted leach] An improved cyanide process for extracting gold from its ores. Addition of hydrogen peroxide to the system improves the yield of gold and reduces the usage of cyanide. First operated in South Africa in 1987. 

Salsigne A cyanide process for extracting gold from ores containing arsenic or antimony. Pre-treatment with a lime slurry reduces cyanide losses. 

Silver is widely distributed throughout the world. It rarely occurs in native form, but is found in ore bodies as silver chloride, or more frequently, as simple and complex sulfides. In former years, simple silver and gold-silver ores were processed by amalgamation or cyanidation processes, The availability of ores amenable to treatment by these means has declined. Most silver is now obtained as a byproduct or coproduct from base metal ores, particularly those of copper, lead, and zinc. Although these ores are different in mineral complexity and grade, processing is similar. 

Cyanide. Sodium cyanide. [CAS 143-33-9]. NaCN. white solid, soluble, very poisonous, formed (1) by reaction of sodamide and carbon at high temperature, (2) by reaction of calcium cyanamide and sodium chloride at high temperature, reacts in dilute solution in air with gold or silver to form soluble sodium gold or silver cyanide, and used for this purpose in the cyanide process for recovery of gold. The perceniage of available cyanide is greater than in potassium cyanide previously used. Used as a source of cyanide, and for hydrocyanic acid. 

POSTER TITLE Simultaneous Leaching and Solvent Extraction of Gold an Alternative Technique to the Cyanidation Process for recovery of gold... 

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