Process for recovering silver and gold from chloride solutions

US4131454A · kind A · utility

Assignee

• Duisburger Kupferhutte

Inventors

• Norbert L. Piret · Duisburg, DE
• Meinolf Hopper · Duisburg, DE
• Herbert Kudelka · Duisburg, DE

Key dates

• Filing date: Nov 2, 1977
• Grant date: Dec 26, 1978
• Expiry date: Nov 2, 1997

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P10/20
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Process for selectively separating precious metal such as silver and gold from a chloride solution of the precious metals and other heavy metals which involves: PA0 (a) adding finely divided activated carbon to the solution for reduction of gold to gold metal and absorption of the gold metal by the carbon, PA0 (b) adding an aqueous solution of an iodine compound for selective precipitation of further precious metal including the silver, if present. During steps (a) and (b) the pH is below 3 so that hydrolysis with the metal ions does not occur, and the potential of the solution during step (b) is such that no substantial decomposition of the iodine compound occurs. The precipitated precious metal and active carbon are separated, dried, and admixed with an iodine binder, and the resulting admixture is subjected to reduction for formation of a regulus containing the precious metal.