Metal phosphate preparation using boron phosphate

The solid-state conversion of basic magnesium, calcium, zinc, and lead compounds into corresponding crystalline phosphates by the BPO4 method has been investigated at 800 °C and 900 °C. Magnesium hydroxide carbonate is converted at 800 °C into Mg2P2O7 (85%), whereas calcium hydroxide gives 2CaO · P2O5 · B2O3 at 900 °C. Zinc oxide gives at 800 °C the mixture of Zn2P2O7 (90%) and Zn3(PO4)2 (10%), whereas at 900 °C only the former is obtained. In the presence of KCl, at 800 °C, zinc oxide yields KZnPO4, while PbO gives Pb5(PO4)3Cl.