Treatment of waste water from powder blue production with sulphur precipitation-coagulation

Treatment of waste water raised from powder blue production was investigated in this paper. The dosage of alkali used to adjust pH was given, and the influence of NH₃ on solution chemistry was studied. The scheme of sulphur-precipitation coagulation was carried by using the waste water raised from noble metal production. The results show that when the mix is below 10:1 between waste water raised from powder blue production and from noble metal production, it's no need to add Na₂S to make waste water in fit with national drainage standards; but it needs to add Na₂S if the mix is above 10:1. The orthogonal experiment results show that the residual heavy metal is affected by dosage of Na₂S, dosage of PFS, and pH, respectively in a descent order, and when Na₂S dosage is 0.146 g/L and PFS dosage is 1.596 g/L at pH 7.0, the content of heavy metal in waste water can fit with that of national drainage standards.