A method for recovering lead and silver from the following leaching with sulfuric acid of ferrites from zinc concentrates and / or pre-roasted composite concentrates remaining residues.

摘要

1337739 Recovery of lead and silver ASTURIANA DE ZINC SA 26 Nov 1970 [22 Dec 1969] 56207/70 Heading C1A Lead and silver contained in the residues remaining after zinc-containing concentrates have been roasted and treated with acid to dissolve zinc, by leaching the residues at ambient temperature with an acidified solution containing chloride ions. The solution is preferably a saturated solution of NaCl acidified with HCl. If H 2 SO 4 is used to acidify the solution, CaCl 2 is preferably added to precipitate the sulphate as CaSO 4 . CuCl may be added to the solution to promote oxidation of sulphides in the residue. The silver and lead may be recovered from the solution by precipitation as sulphides, or by consectuive cementation. Silver may be precipitated by cementation with lead, and the lead then obtained by cementation with zinc. The zinc may then be recovered as an insoluble salt, washed free of chloride and recycled.