Method for the solvent extraction of zinc
US5135652A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 25, 1990 |
| Grant date | Aug 4, 1992 |
| Priority date | — |
| Expiry date | Oct 25, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S75/961
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Zinc is selectively extracted from zinc sulfate solutions that may also contain sulfuric acid and amounts of other metals with an organic extractant mixture containing both organic substituted phosphoric acid and organic substituted thiophosphinic acid. The phosphoric acids are preferably chosen from mono- and di-2-ethylhexylphosphoric acids and mixtures thereof, and the phosphinic acids are preferably chosen from bis- 2, 4, 4-trimethylpentyl mono- and dithiophosphinic acids. The use of an extractant mixture of the dithiophosphinic acid with mono- and di-2-ethylhexyl phosphoric acids or an extractant mixture of the dithiophosphinic acid with di-2-ethylhexylphosphoric acid is preferred. The pH during zinc extraction is controlled at a value in the range of about 1.3 to 5. Control of pH is carried out either by neutralization or by acid extraction with an organic amine-type extractant. The acid content of the feed solution may be reduced by neutralization or acid removal by dialysis. The solvent extraction of zinc or zinc and acid from feed solution may be carried out co-, counter- or cross-currently in one or more stages. The preferred extraction method is dualcircuit, side-by-side,…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.