Phosphoric acid purification
US4154805A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1977 |
| Grant date | May 15, 1979 |
| Priority date | — |
| Expiry date | Oct 14, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/234
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Wet process phosphoric acid prepared by treating phosphate rock with sulfuric acid and separating calcium sulfate, is purified to obtain a purified phosphoric acid by (a) an acid extracting section contacting the wet process phosphoric acid and a phosphoric acid solution containing impurities obtained in the scrubbing section with an organic solvent in the presence of the hydrochloric acid required for extracting a substantial amount of the phosphoric acid component; (b) a scrubbing section contacting the extract obtained in the acid extracting section with aqueous phosphoric acid or water while maintaining the chloride ion concentration in the aqueous phase in the range of 20 to 40 g/liter as Cl; (c) an acid stripping section contacting the purified extract obtained in the scrubbing section with water and (d) an adsorbing section contacting the extracted phosphoric acid obtained in the acid stripping section with an anion-exchange resin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.