Method for producing ammonium polyphosphate
US4832928A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1987 |
| Grant date | May 23, 1989 |
| Priority date | — |
| Expiry date | Jul 21, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/405
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of continuously producing ammonium polyphosphate by the reaction of urea and polyphosphoric acid, over a wide range of molecular weights, in a pre-mix slurry, under controlled temperature of about 315.degree.+/-15.degree. C. The slurry is reacted on a hot, continuously moving surface and forms ammonium polyphosphate in an ammonia atmosphere. Preferably, the pre-mixed slurry is added to a screw-type extruder, where the material comes in contact with the ammonia along the preheated moving surfaces of the extruder. The ammonium polyphosphate is scraped from the extrusion screw into a container with minimum handling. The material can be ground to a finer consistency if desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.