Pptn of lead and silver - from zinc ore residues as filterable sulphi

摘要

Recovery of Pb and Ag and precious metals extracted from residues from electrolytic zinc prodn and from oxidation of Pd-Zn mixtures for example by leaching with aq. chlorides brines amines or ammonical ammonium sulphate by precipitation as easily filterable sulphides using elementary sulphur or sulphides of hydrogen, Na, K and NH4 (NH4)2S in a quantity in excess of stoichiometric and a filtration rate of 0.2 gallon/sq.ft./min. at 20-70 degrees C for 1 hr or with polysulphides at 70 degrees C.