Precipitation of Gold from Cyanide Solutions by Metallic Iron and Some of Its Compounds.

Compounds of divalent iron precipitate gold from cyanide solutions. The degree of completeness of the precipitation depends on the conditions under which the process is carried out. Upon intense stirring of the slurry, followed by aeration in a highly alkaline medium, the precipitated gold goes back into the solution. In analyzing the work of a factory or shop carrying out cyanidation of sulfide ores, concentrates, or the products of their roasting at low or medium temperatures, it should be borne in mind that part of the gold loss may be caused by incomplete passage into the solution of metal absorbed by compounds of divalent iron.