Precipitation of phosphorus as NH4[MgPO4] · xH2O in the presence of citrates, d,l-tartaric acid, and their complexes with vanadium and molybdenum

For determination of phosphorus in Mo-V-phosphoric heteropoly acid solutions, it must be separated from considerable amounts of vanadium and molybdenum by precipitation as NH 4 [MgPO 4 ] · x H 2 O. It is shown that the known method of its precipitation in citrate medium is too slow because of low reactivity of Mg(II)-citrate complexes. We propose to precipitate NH 4 [MgPO 4 ] · x H 2 O in the presence of d,l -tartaric and next to purify the prepared precipitate. This method permits to shorten preparation of the pure precipitate in several times.