METHOD FOR PROCESSING SECONDARY GOLD-CONTAINING MATERIAL TO PURE GOLD Russian patent published in 2001 - IPC

FIELD: hydraulic metallurgy of noble metals, namely methods for extracting gold out of concentrates, waste materials of electronic and jewellery industry branches for obtaining pure gold. SUBSTANCE: method comprises steps of gold extraction and its purification. All processes of gold extraction are realized during one technological operation by means of electrolysis at charging raw material to titanium anode basket covered with catalyst and adding in electrolyte salt of variable-valence metals and complexion agent. Gold is deposited out of electrolyte; remaining metals are separated on cathode. According to first variant of invention purification process is realized by any well known method. According to second variant of invention purification is realized by anode dissolution of gold extracted at first step in aqueous solution of aurohydrochloric acid at applying alternating asymmetrical electric current for depositing pure gold on cathode, argentum chloride - on electrolyzer bottom, collecting additives in electrolyte and extracting them out of electrolyte together with part of gold for depositing onto additional cathode provided with anionite or porous diaphragm. Concentration of gold and chlorides in electrolyte is controlled by means of partial electric current passing through additional cathode. Precipitation from additional cathode is returned to first step of process. In order to eliminate deposition of gold onto bottom of electrolyzer, anodes are placed to titanium basket covered with catalyst. EFFECT: ecologically safe treatment of gold- containing raw material, high degree of product purification, minimum metal losses, lowered power and reagent consumption. 9 cl, 3 ex