Stabilized ammonium orthophosphate suspensions
US5022913A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1989 |
| Grant date | Jun 11, 1991 |
| Priority date | — |
| Expiry date | Aug 28, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC05B7/00
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
An improved batch process for the production, in equipment readily available at the fertilizer dealer level, of high-analysis stable ammonium orthophosphate suspension fertilizers effected by the ammoniation of solid intermediates derived from wet-process orthophosphoric acids or combinations of the solid intermediates with such wet-process type acid or other impure phosphoric acids. Fluorosilicic acid, a by-product of the phosphate industry which is readily available and relatively inexpensive, is utilized as a source of fluoride. The fluorosilicic acid is added to the batch formulation prior to the ammoniation step thereby allowing the fluorosilicic acid to be converted to ammonium fluoride. Subsequently, the metallic impurities are allowed to precipitate as fluoride compounds instead of the usual troublesome impurity-phosphate-water gels which have been identified as causing complete destruction of suspension fluidity during storage. This specific sequencing of process steps produce suspensions which can be stored for substantial periods of time without becoming thixotropic and/or so thick that they have to be diluted before use as is the case in suspensions prepared by prior ar…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.