Processing roasted zinc blende leaching residues - by treating with sulphuric acid and ground zinc sulphide, neutralising and precipitating constituents

摘要

The treatment comprises (a) leaching the residue in one step with sulphuric acid with the addn. of activated ground Zn sulphide, separating the insoluble fraction and treating without further leaching (b) neutralising the soln. to pH max 2, (c) treating with Zn dust at a temp. 80 degrees C to b.p., sepg. the cement Cu, (d) neutralising the soln. to pH 4-5, (e) sepg. the residue formed in (d) and after pptn. of Fe in the form of hematite recycling the purified soln. to the Zn prodn. process. Method is more economical and can be carried out at lower temp. than known processes. By-products can be recycled to the Zn roasting process.