Process for the purification of wet-process phosphoric acid by removal of cadmium
US4634580A · kind A · utility
6Cited by
6References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 14, 1984 |
| Grant date | Jan 6, 1987 |
| Priority date | — |
| Expiry date | Dec 14, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/14
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process for the removal of cadmium contained in wet-process phosphoric acid by flotation by means of a cadmium-collector anionic surface active agent and an injected gas in the presence of other impurities including iron and possibly uranium which is characterized in that, in order to improve the removal of cadmium, the iron contained in the phosphoric acid in the trivalent state is reduced to the divalent state before the cadmium collector is introduced into the medium to be purified by flotation. The collector agent is selected from the group of dithiophosphoric acid esters and the alkali metal salts thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.