Process of leaching precious metals
US9150942B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 14, 2012 |
| Grant date | Oct 6, 2015 |
| Priority date | — |
| Expiry date | Aug 14, 2032 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P10/20
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The invention relates to modifications of a non-ammoniacal thiosulfate process of leaching precious metals (e.g. gold or silver) from precious metal-containing ores. The process involves leaching the ore with an aqueous lixiviant containing a soluble thiosulfate other than ammonium thiosulfate, a copper compound and an organic compound that serves as a copper ligand (i.e. a ligand-forming compound). Four modifications of this process are effective for increasing the amount of precious metal that can be extracted, reducing the consumption of materials, or for improving the rate of extraction. These four process, which may be used singly or in any combination, include (a) additions of soluble lead (e.g. as lead nitrate), (b) additions of thiourea, (c) increases in dissolved oxygen, and (d) increases of temperature at ambient pressure. This avoids the use environmentally harmful chemicals and allows for extraction from a variety of ores, e.g., containing substantial amounts of sulfides and/or quartz.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.