Preparation of granular sodium tripolyphosphate hexahydrate with low friability
US4315898A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 1980 |
| Grant date | Feb 16, 1982 |
| Priority date | — |
| Expiry date | Jun 30, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/418
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Screen undersize anhydrous sodium tripolyphosphate particles, containing at least 2 weight percent of an alkali metal pyrophosphate, preferably sodium pyrophosphate, are moisturized with from about 145% to about 185% by weight of the theoretical amount of water to convert the anhydrous sodium tripolyphosphate into the hexahydrate form. The material is agitated during moisturization to keep the temperature below about 80.degree. C., and the moisturized material is dried at a temperature below 80.degree. C. to remove most of the free moisture. The product recovered from the drying step is a granular sodium tripolyphosphate hexahydrate product having a bulk density within the range of 0.59 g/cc to 0.64 g/cc and a friability of no higher than 30%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.