Leaching of pyritic zinc ores for recovery of zinc - where insol. residue is melted to produce disposable slag and matte. contg. noble metals

摘要

Sulphidic Zn ores and/or concentrates are leached with cell acid under oxidising conditions to obtain elementary sulphur. The soln. obtd. is sepd. from the insol. residue, and is purified before being fed into an electrolysis cell for winning Zn and providing the cell acid used in leaching. The insol. residue is dried and then melted to burn off the sulphur, and to obtain a disposable slag and a sulphide matte contg. Cu, Pb and noble metals. The gas obtd. in the melting stage contains easily volatile metals and metal cpds., esp. Zn, which are condensed. The ore is pref. milled before leaching, which is pref. undertaken at ca. 100 deg.C in the presence of O2, Fe (II) and Fe (III) ions, without pressure. A disposable slag is obtd. economically, i.e. a slag which does not pollute the environment; the energy required is reduced; and simpler processing plant can be used.