Oxidation/reduction process for recovery of precious metals from MnO.sub.2 ores, sulfidic ores and carbonaceous materials
US5232490A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1992 |
| Grant date | Aug 3, 1993 |
| Priority date | — |
| Expiry date | Mar 3, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P10/20
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for separating precious metals from an MnO.sub.2, sulfidic or carbonaceous refractory ore or refractory feed such as tailings is provided. The process includes the step of leaching a feed with a leach liquor that includes an acid selected from the group of HCl and H.sub.2 SO.sub.4 in the presence of MnO.sub.2 and a reductant. A source of chloride ion is added to the leach sufficient to dissolve at least about 50% of the precious metals present in the ore. A portion of the leach is removed and precious metals are recovered from the removed portion. A portion of the chloride carrier is recycled to the leach to carry chloride values to the leach. In one embodiment, HCl is regenerated by pyrohydrolysis, which minimizes harmful waste products. The present process can advantageously avoid the use of noxious reagents.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.