During the copper refining process, impurities in the anode either dissolve into the electrolyte or form an anode slime. When arsenic, antimony and bismuth enter the electrolyte, they can undergo a number of different reactions depending on their respective concentrations, as well as on the presence and concentrations of other elements. Arsenic enters the electrolyte as As(III), and it is gradually oxidised to As(V). Under these circumstances, insoluble antimony and bismuth arsenates are formed causing both issues with tank house circulation pipework fouling and copper cathode nodulation.

In the past refineries have undertaken multi-step purification processes to address impurity build up, these have included the use of ion exchange techniques, unfortunately issues of resin poisoning and high regeneration acid usage have made these processes both expensive and difficult to operate.

Kurion has addressed the issues of resin poisoning and fresh regeneration acid usage, now copper refineries have a viable technology to remove antimony and bismuth from their copper electrolytes.