Precipitation of zinc sulfide by hydrolysis of thioacetamide in the presence of hydrazine hydrochloride

Zinc sulfide can be precipitated quantitatively from solutions buffered at pH 2 using thioacetamidehydrazine hydrochloride mixtures as precipitants. Optimum results are obtained using equimolar quantities of thioacetamide and hydrazine hydrochloride. Coprecipitation of cobalt sulfide was studied using citrate-citric acid, and sulfate-bisulfate buffers. Optimum separations are achieved using a sulfate-bisulfate buffer containing ammonium thiocyanate.