GB279156A - Improvements in and relating to processes for extracting or removing metals from materials containing the same - Google Patents

Abstract

279,156. Powell, A. R., Deering, E. C., and Johnson, Matthey & Co., Ltd. July 19, 1926. Amalgamating; mercury, quickening.-In a process for extracting non-amalgamable metals of the platinum group, or alloys or minerals consisting of or containing such metals, particularly applicable to ores containing a high proportion of basic substances, a coating of an amalgamable metal such as copper, tin, or silver is deposited on the platinum, &c., from an alkaline solution containing also a substance which prevents precipitation of the hydrate of the coating metal such as ammonia, cyanides, tartrates, citrates, and sugars, or a solution of a double salt of the coating-metal with one of such substances such as sodium copper cyanide, and preferably containing also a substance which keeps the surface of the deposited metal and of the mercury bright and clean, such as ammonia or caustic soda. The treated material is subjected to the action of mercury or an amalgam whereupon the coated particles are taken up by the mercury and separated from the mixture. The treated material may be agitated with mercury or amalgam, or passed over an amalgamated plate; or a soluble mercury salt may be used from which the mercury is obtained by precipitation with another metal The metal coating may be deposited from the alkaline solution electrolytically or by means of a reducing agent. The treatment with mercury or amalgam may be effected either after the deposition of the coating metal or simultaneously therewith.