Gold Refining at Tokyo Refinery

Abstract

Tokyo Refinery of Chugai Mining Co., Ltd. located in Keihinjima, Oota-ku, Tokyo, started its operation in August 2005. We operates a solvent extraction process for gold recovery refining. Solvent extraction can provide significant reductions in operational costs. High grade secondary metallic sources with a high precious metal content, such as jewelry scrap, are first brought into solution with aqua regia. Silver forms insoluble AgCl which is separated and recovered by filtration. Gold is extracted by the solvent extraction schemes into the organic phase, and scrubbed with hydrochloric acid for impurity removal. Gold is reduced and recovered from the organic phase with reducing agent. The capacity of gold refining process is 520kg per month. The all manufacturing processes take only three days.