METHOD FOR SYNTHESIS OF METAL SULFATE-PHOSPHATES Russian patent published in 2017 - IPC C01B17/96 C01B25/26 C04B35/447 

FIELD: chemistry.

SUBSTANCE: invention can be used in the production of thermomechanically stable materials and products based on them, requiring high resistance to heat shock and resistant to sudden temperature changes. The method for the synthesis of metal sulfate-phosphates involves the determination of the maximum permissible temperature range, within which the synthesis proceeds without loss of sulfur. The starting reagents are selected to facilitate the reaction with the formation of intermediate simple sulfates, the decomposition temperature of which is within the maximum allowable synthesis temperature range. Solutions of metal salts are produced from the initial reagents. Solutions of metal salts are mixed with solutions of acids H₃PO₄ and H₂SO₄. Stepwise drying of the reaction mixture is performed at the temperatures of 90°C and 130°C. Further heat treatment of the reaction mixture within the maximum permissible temperature range is carried out for 6-48 hours with dispersion and control of the chemical and phase composition by the methods of electron probe microanalysis and radiography after each heat treatment. Metals with similar ionic radii are selected and the combinations of the following metal cations are used: M⁺ - Na and K, M²⁺ - Mg, Ba, Pb, M³⁺ - Cr, Fe, M⁴⁺ - Zr. Nitrates, metal chlorides, chromium acetate are used as starting reagents.

EFFECT: preventing the loss of sulfur due to its binding to an intermediate sulfur-containing precursor with a high decomposition temperature.

6 cl, 2 dwg, 8 tbl, 4 ex