Process for removing fine solids from phosphoric acid by vacuum filtration
US4313919A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1980 |
| Grant date | Feb 2, 1982 |
| Priority date | — |
| Expiry date | Jul 15, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/235
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A process, for removing solid impurities from impure phosphoric acid containing solids, comprising: (a) passing said acid at an elevated temperature through a filter cake of a phosphoric acid-resistant filter aid supported on a porous medium, thereby to cause at least a portion of said solid impurities of said acid to be filtered therefrom and to be retained by said filter cake; (b) contacting at least a portion of said filter cake with a displacing liquid, maintained at a temperature and in an amount sufficient to cause at least a portion of the acid which remains in said filter cake to pass through said filter cake without fracturing said filter cake; (c) collecting said filtered acid which passes through said filter cake; and (d) removing an impurity-containing portion of said filter cake after contact with said acid and displacing liquid, thereby to present a fresh surface for subsequent filtration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.