MAGNESIUM PHOSPHATE FOR STABILIZING CALCIUM DIHYDROGEN PHOSPHATE DIHYDRATE

摘要

PURPOSE:To easily manufacture high purity amorphous magnesium phosphate contg. bound water as octahydrate or lower and having a superior effect of stabilizing calcium dihydrogen phosphate dihydrate as a base for toothpaste. CONSTITUTION:A water-soluble alkali metallic phosphate such as sodium dihydrogen phosphate is mixed with an Mg salt such as MgSO4 in the form of aqueous solns., and the mixture is adjusted to 9-11pH with an alkali substance and kept at 50 deg.C to produce magnesium phosphate docosahydrate. The crystals are very large and free from impurities contained in the starting materials, and they are very easily separated from the mother liquor and washed. The docosahydrate is then dried and dehydrated. At this time, the temp. is made relatively high so as to accelerate the evaporation of water, and an internal heat type drier from which evaporated water is rapidly released is used. By carrying out the dehydration until the docosahydrate is reduced to octahydrate or lower on calculation, amorphous magnesium phosphate contg. bound water as octahydrate or lower is obtd.