METHOD FOR THE SYNTHESIS OF METAL PHOSPHATES IN OXIDATION STATE III Russian patent published in 2021 - IPC C01B25/45 C01F17/30 C30B29/14 C04B35/447 

FIELD: ceramic insulators production.

SUBSTANCE: invention can be used in the manufacture of ceramic insulators and ferromagnets, matrices for the immobilization of toxic industrial waste. The method for the synthesis of metal phosphates in the oxidation state III includes the preparation of solutions of metal salts from the initial reagents, which are used as nitrates, metal chlorides, chromium acetate. Solutions of metal salts are mixed with a solution of H₃PO₄ and stage-by-stage drying of the reaction mixture is carried out at 90°С and 200°С for complete dehydration of the product. Then stage-by-stage heat treatment of the reaction mixture is carried out at 600-1000°С for 12-48 hours, dispersion and control of the chemical and phase composition by methods for electron probe microanalysis and X-ray diffraction after each heat treatment. Combinations of the following metal cations are used in the chemical composition of polycrystalline RR'(PO₄)₃ phosphates: R - Bi, Sb_xBi_1-x (0 ≤ x ≤ 1), R' - Fe₂, Cr₂, Al_xCr_2-x (0 ≤ x ≤ 0,5) or R - Sb, La, Ce, Pr, Nd, R' - Cr₂.

EFFECT: invention improves the reactivity of the charge, to reduce the duration of the process and the temperature of obtaining the product.

4 cl, 2 dwg, 5 tbl, 4 ex