Method of producing metallic lead and silver from their sulfides
US3961941A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1975 |
| Grant date | Jun 8, 1976 |
| Priority date | — |
| Expiry date | May 19, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22B11/04
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for producing metallic lead and silver from materials such as ores and concentrates containing the corresponding sulfides and particularly a mixture of minerals such as galena and tetrahedrite in which process the minerals are initially roasted under neutral conditions which include a non-oxidizing or even slightly reducing atmosphere at an elevated temperature for a time equivalent to about 1.5 hours at about 550.degree.-600.degree.C. to produce a roasted mineral product in which the roasting causes certain unidentified changes but with the resulting roasted product being more easily leachable so that the process of removing the silver and lead can be greatly simplified. The leaching and separating of the silver and lead includes subjecting the neutral roasted material to a ferric leach such as with an aqueous solution of ferric chloride to convert the lead and silver sulfides to lead and silver chloride, then subjecting the solid residue from this first leaching to a second leaching with aqueous sodium chloride brine to dissolve these lead and silver salts followed by separating the lead and silver salts from the brine leached material to leave a final solid as a final …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.