Hydrometallurgical Processing of Precious Metal Ores

Abstract Precious metals have been extracted since antiquity. However, the advent of modern day hydrometallurgical technique began less than a hundred years ago. Today, cyanidation extraction of precious metals supersedes all hydrometallurgical processes and its versatility is appreciated more and more as the breadth of its applications is widened through modifications such as dump and heap leaching, carbon-in-leach. carbon-in-pulp, chemical and autoclave oxidation, roast-leach, and flotation-cyanidation. This paper reviews the advances that have taken place in the hydrometallurgical extraction of precious metals in the last century including the latest development such as bacterial oxidation and leaching with non-cyanide reagents such as thiourea and thiosulfate. Efforts have been made to cover the theoretical aspects as well as practical and economic aspects of these developments.