Advances in the treatment of CuSO4-H2SO4-As-Sb-H2O solutions by electrodialysis
The treatment of aqueous CuSO4-H2SO4-As-Sb solutions by electrodialysis in order to separate and concentrate species of interest has recently been studied. Results show that it is possible to separate copper from arsenic in electrodialysis cells. The separation of copper from antimony is also possible. Transport rate ranges that could be achieved, depending on experimental conditions, are 0.2 to 0.6 mol per hour per square metre of membrane for copper, 0.65 to 2.8 for sulphate, and 0.016 to 0.03 for arsenic. Transport rates for antimony were inconclusive due to its very low solubility in the studied systems. Solution agitation and increasing temperature markedly increased the process rates. Advancements in this area require further work in both the thermodynamics (speciation) and kinetics of complex CuSO4-H2SO4-H2O systems, where impurities, other than As and Sb, and additives should be taken into account to gain a deeper understanding of the application of ED to copper electrorefining electrolytes.