Moisturized compositions of hydrate-forming phosphates and methods for preparation thereof

DETAILED DESCRIPTION Among the several objects of the invention, therefore, may be noted the provision of particulate, crystalline compositions of hydrate-forming phosphates having improved rates of hydration; the provision of such compositinns that have more consistent rates of hydration; the provision of such compositions, particularly those in granular form, that require relatively low concentrations of water, yet have such desirable rates of hydration; the provision of such compositions in powder form that resist caking and are free-flowing; the provision of particulate, crystalline sodium tripolyphosphate compositions that have improved rates of hydration; the provision of such sodium tripolyphosphate compositions that have more consistent rates of hydration; the provision of such sodium tripolyphosphate compositions, particularly those in granular form, that require relatively low concentrations of water; the provision of such sodium tripolyphosphate compositions in powder form that resist caking and are free-flowing; and the provision of a process for producing such sodium tripolyphosphate compositions.
In accordance with this invention, there has been discovered a particulate, at least partially hydrated, crystalline form of phosphate composition comprising a sodium tripolyphosphate, sodium pyrophoshate or trisodium phosphate and from about 0.
1% by weight to about 23% by weight added water, said water at the time of addition to the phosphate containing in solution sufficient surfactant to provide the composition with from about 0.
2 ppm to about 125 ppm surfactant.
Compositions of this invention have been found to have a rate of hydration superior to those of conventional crystalline phosphate compositions in those instances of incomplete hydration and in all instances superior product uniformity.
The powder form of the compositions of this invention have been found to have greatly reduced caking tendency and in most instances are practically non-caking.
In the granular form, compositions of this invention also have been found to have greatly reduced caking tendency and are practically non-caking in practice because the granular form can be prepared by addition of about one-half as much water as required in prior art processes such as in U