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Production of High-purity Gold from Zinc Precipitates and Steel Wool Cathodes by Hydrometallurgical Refining

G. E. McClellandMatt D. WroblewskiJudith A. Eisele

出版	U.S. Department of the Interior, Bureau of Mines, 1985
URL	http://books.google.com.hk/books?id=zlwGjtFElV8C&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋The Bureau of Mines investigated chemical methods for producing high- purity gold from precious-metal-bearing zinc precipitates and steel wool cathodes. Precious-metal-bearing zinc precipitates and steel wool cathodes are unrefined products from conventional cyanidation and heap leaching-cyanidation operations. The zinc precipitates contained 14,40 pct Au and 0.35 pct Ag. The precious-metal-bearing steel wool cathodes contained 20.65 pct Au and 4.84 pct Ag. The precipitates and cathodes were treated with dilute acid to solubilize the silver and/or base metals. The gold-bearing residue was leached in dilute aqua reqia to solubilize the gold. High-purity gold was precipitated from the aqua regia solution with oxalic acid, sulfurous acid, sodium bisulfite, and gaseous sulfur dioxide. The leaching-precipitation experiments recovered 99.9 pct of the gold. The gold precipitates ranged in fineness from 997 to 999 fine. The chemical refining method provides a viable technique for the smaller operator to produce high-purity gold without using pyrometallurgical refining methods.