Postprecipitation of zinc with homogeneously precipitated copper sulfide

The postprecipitation of zinc ion onto copper sulfide which has been precipitated from homogeneous solution using thioacetamide has been investigated under various conditions. The zinc carried increases with increasing time, increasing concentration of zinc, increasing digestion temperature, increasing thioacetamide added, and decreasing acid concentration. On the basis of these and several other special observations, it is believed that the postprecipitation is a result of adsorption of bisulfide ion on the surface of the copper sulfide, this adsorbed layer then reacting with the zinc ion.