Rapid Analysis of Copper in Cyanide Baths Using EDTA

When ammonium persulphate is added to copper cyanide plating solution, the latter is, without heating, decomposed into copper sulphate, ammonia and carbondioxide, according to the following equation. 2Na2Cu(CN)3+7(NH4)2S2O8+12H2O→2CuSO4+2 Na2SO4+10(NH4)2SO4+6CO2↑ The solution is alkalized with ammonia, and then titrated by EDTA standard solution using PAN as indicator. Thus the copper content in the copper cyanide baths is easily and rapidly analyzed, yet without being affected by the iron content in the bath.