Back to results
US 4,225,342 AGranted
Treatment of zinc plant leach residues for recovery of the contained metal values
AssigneeTexasgulf Inc.
InventorsGeorge M. Freeman, David E. Nightingale
Life of this patent
Estimating the term…
Abstract
A process for treating zinc plant leach residues for the recovery of the lead, silver, and tin values contained therein is disclosed. The process includes the treatment of the zinc plant residue with concentrated sulphuric acid followed by water leaching and other hydrometallurgical steps to separately recover the lead, silver and tin.
Claims31
A process for the recovery of lead, silver and tin from zinc plant leach residues, comprising the steps of:
- (a) sulphating the zinc plant leach residue to form a dry cake wherein the bulk of the metal values contained therein are in their sulphate form;
- (b) water leaching the silver and tin from the sulphated cake;
- (c) separating the insoluble lead residue from the water leach solution;
- (d) recovering the silver from the leach solution by precipitation;
- (e) treating the leach solution to reduce the iron content;
- and
- (f) recovering the tin contained in the residual leach solution by precipitation.
4 more elements
A process for the recovery of lead, silver and tin from zinc plant leach residue, comprising the steps of:
- (a) sulphating the zinc plant residue with sulphuric acid at a temperature of about 200.degree. C. for about 16 hours to form a dry cake wherein the metal values contained therein are in their sulphate form;
- (b) water leaching the sulphated cake at about 80.degree. C. for approximately 1/2 to 1 hour;
- (c) separating the insoluble lead residue from the water leach solution by filtration;
- (d) increasing the chloride ion content of the leach solution using sodium chloride to about 200 ppm to precipitate the silver as silver chloride and separating said silver chloride from the leach solution by filtration;
- (e) reducing the iron content of the leach solution to about 2 g/l by the addition of zinc calcine at a pH of about 1.8 and a temperature of about 90.degree. C. to about 95.degree. C.;
- (f) recovering the tin contained in the residual leach solution by adjusting the pH of said solution to about 4.5 to 5 such that the tin is precipitated as metastannic acid.
3 more elements
Dependencies are inferred from the claim text.