Method for producing ammonium phosphate which is substantially free of arsenic
US4147757A · kind A · utility
2Cited by
1References
25Claims
0Family size
Assignee
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Key dates
| Filing date | Nov 18, 1977 |
| Grant date | Apr 3, 1979 |
| Priority date | — |
| Expiry date | Nov 18, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/28
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for producing ammonium phosphate that is substantially free of arsenic which comprises: PA1 (a) reacting crude phosphoric acid containing dissolved arsenic having a +5 valence state with ammonia and arsenic-reducing agent in sufficient proportions to form an ammonium phosphate solution and to reduce the arsenic from the +5 valence state; PA1 (b) forming ammonium phosphate crystals from said solution, leaving a mother liquor that contains substantially all of said arsenic; and PA1 (c) recovering said ammonium phosphate crystals that are substantially free of arsenic from said mother liquor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.