ELECTRODIALYSIS OF COPPER-THIOUREA SOLUTIONS

Thiourea is used as a complexing agent for the treatment of precious m etal ores and manufacturing and thiourea is sometimes present in aqueo us solutions containing copper ions. The purpose of this work is to de termine if electrodialysis can be used for the recovery of Cu2+ ions f rom solutions containing thiourea. The solutions studied contained sod ium and copper ions as well as thiourea. The transmembrane fluxes of N a+ and Cu2+ are measured under a constant current. For the transport o f the two cations, the current efficiency is decreased when thiourea i s present in the solution. This is due to the formation of Cu (I) thio urea complexes, which create several positively charged species as a p roduct of thiourea oxidation and which remain irreversibly bound insid e the membrane material.