Preparation of phosphates
US3956464A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1971 |
| Grant date | May 11, 1976 |
| Priority date | — |
| Expiry date | Apr 19, 1991 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC05B7/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Potassium phosphates useful as fertilizer materials, are produced by the reaction of phosphate rock or a solubilized form thereof, concentrated sulfuric acid and potassium hydrogen sulfate wherein the potassium hydrogen sulfate is added in a controlled manner and preferably in admixture with at least a portion of the sulfuric acid, the precipitated calcium sulfate precipitate is removed and the filtrate processed for recovery of the potassium phosphates. In further embodiments, high-sulfate containing filtrates are treated to lower the sulfate ion content of the products and effect partial neutralization by any of several methods such as by treatment thereof with fresh phosphate rock or source of calcium ion such as calcium oxide, alternatively or successively, and the resulting solution is used as a fertilizer, or liquids are removed and the solids are dried and/or dehydrated for recovery of the potassium phosphate compounds. Also methods are provided for the addition of nitrogen values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.