Purification of phosphoric acid
US4208389A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 1979 |
| Grant date | Jun 17, 1980 |
| Priority date | — |
| Expiry date | Feb 6, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/462
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Wet process phosphoric acid prepared by treating phosphate rock with sulfuric acid is purified by extracting said wet process phosphoric acid with an organic solvent containing an equilibrium concentration of phosphoric acid in a first extraction section such that substantial extraction of phosphoric acid from said wet process phosphoric acid is prevented while the organic impurities in said wet process phosphoric acid are substantially extracted and under conditions which prohibit significant extraction of iron impurities into said solvent extractant, extracting the extracted wet process phosphoric acid of reduced organic impurity content with an organic solvent in a second extraction section, returning a portion of the solvent from the second extraction section to the solvent extraction phase of the first section, removing the organic impurities from the solvent phase which is obtained from the first extraction section, and returning at least a portion of the solvent from which the organic impurities have been removed to said second extraction section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.