Process for making phosphoric acid
US4402923A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 2, 1981 |
| Grant date | Sep 6, 1983 |
| Priority date | — |
| Expiry date | Sep 2, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/223
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A phosphate rock slurry, which may be used in the production of wet process phosphoric acid, is provided by wet grinding the rock with partially neutralized, acid water. In one aspect, wet process phosphoric acid is made by advantageously recycling mineral acid waste water effluent of the process. All or a portion of the effluent can be at least partially neutralized with neutralizing agent, e.g., by contact with the base-forming constituents of phosphate rock or extraneous neutralizing agent, e.g., preferably ammonia, to provide a mixture which is wet ground to produce a processable slurry. In one particularly preferred aspect, all of the acid water is at least partially neutralized with phosphate rock and a portion of this acid water is advantageously further neutralized with an extraneous neutralizing agent. The slurry is provided by such neutralization at a pH compatible with the milling, e.g., grinding, media utilized. The use of acid water permits the use of mixtures having high solids content in the mill and thus also reduces the amount of water required to wet grind the mixture. The wet ground processable phosphate rock slurry is advantageously used in the production of pho…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.