Copper Refineries Ltd (CRL) is one of the world's leading electrolytic copper refineries, capable of producing 300,000 tonnes of 99.995% pure copper cathode per year through Glencore's proprietary IsaKIDD process.
Copper anodes, 99.7% pure copper plates produced at our Mount Isa Mines Copper Smelter, are transported by rail to CRL. Copper anode is then refined using the IsaKIDD electrolytic refining process.
Copper anodes are submerged in an acidic copper sulphate solution, between stainless steel mother plates in the Refinery Tankhouse.
A low voltage electric charge is fed through the tanks, and over seven days this causes the copper anode dissolve into the copper sulphate solution, where the copper content is separated from any remaining waste material, which falls to the bottom of the tank. The positively charged copper content is redeposited on the stainless steel mother plate as 99.995% pure, premium ISA brand copper cathode.
The copper cathodes are then stripped from the stainless steel plates, washed, sampled and bundled for sale to domestic and international customers around the world through Glencore Port Operations at the Port of Townsville.
The impurities left over after the electrolytic refining are called tankhouse slimes. Slimes contain a range of other valuable minerals including silver and gold which are transported from the Port of Townsville to customers globally for further refining.