Development of a process for recovery and recycling of rhodium from waste metal in the semijewels industry

• Grant number: 03/07623-1
• Support type: Research Grants - Innovative Research in Small Business - PIPE
• Duration: June 01, 2004 - August 31, 2007
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Transformation Metallurgy
• Principal researcher: Marcos Spitzer
• Grantee: Marcos Spitzer
• Company: Reaquim Indústria e Comércio de Produtos Químicos Ltda. - ME
• City: Santa Bárbara D'Oeste

Abstract

This project aims to apply and refine a process for the recovery of metal rhodium deriving from different stages in the industrial production of semijewels. The process should consist of chemical or electrochemical stages, or both combined, for the separation of rhodium from the metal substrate and its transformation into rhodium sulfate. The immediate application of rhodium sulfate will be its introduction into electrodeposition baths for the manufacture of semijewels. In the jewel and semijewel industry, rhodium is deposited in fine layers on pieces such as earrings and rings, initially made up of a base metal, generally copper. At the same time as the pieces are being covered, the tying wires, hooks and electrical contacts in the electrochemical baths are also covered with rhodium. The last two are reused for a new electrodeposition, while the tying wires are useless after removing the pieces from the hook. To reuse the rhodium fixed on these wires, this project proposes to implement and evaluate different stages: to verify the purity of the starting material; to carry out the separation of the rhodium from the base metals by means of chemical or electrochemical dissolution; dissolution of metal rhodium, using procedures of electrochemical dissolution or in melted salts; production of rhodium sulfate and purification of that salt. With subsequent mastery of these techniques, rhodium may be transformed into other salts. (AU)