Purifying phosphoric acid contg. magnesium, iron and aluminium cpds. - by heating the acid to ppte. the metal pyrophosphate

摘要

Phosphoric acid contg. at least one of the ions Mg, Fe or Al is purified by being heated under conditions of temp., pressure, time and concn. such that the impurities (and when Mg is the major constituent, >60% of the Mg) are pptd. as metal pyrophosphates.