METHOD OF PRODUCING POWDERED SINGLE-PHASE TUNGSTEN-CONTAINING HYDROXYAPATITE BY CHEMICAL COPRECIPITATION Russian patent published in 2024 - IPC C01B25/32 B01J37/03 B01J27/18 

FIELD: chemistry.

SUBSTANCE: invention can be used when producing powders of tungsten-containing hydroxyapatite used as catalysts or catalyst substrates. To obtain single-phase powders of tungsten-containing hydroxyapatite by chemical coprecipitation, 4-aqueous calcium nitrate and ammonium hydrophosphate are dissolved in water to obtain solutions with concentrations of 1 to 5 M. Ammonium paratungstate is dissolved in water in a volume equal to the volume of ammonium hydrophosphate solution, and a solution with concentrations of up to 0.2 M is obtained. Calcium nitrate solution is stirred with the help of a stirring device at rate of 300–600 rpm, pH of the solution is adjusted to values of 9–11 with aqueous ammonium solution. Simultaneously, solutions of ammonium hydrophosphate and ammonium paratungstate are added drop by drop while maintaining pH of the solution at a constant level in range of 9–11. Obtained precipitate is aged in a mother solution at a constant temperature of 37 °C for 21 days. Obtained suspension is then filtered and dried at 60 °C for 12 hours.

EFFECT: invention enables to obtain powder of single-phase tungsten-containing hydroxyapatite with tungsten content of up to 4 mol.% without using expensive equipment.

1 cl, 1 dwg, 1 tbl, 2 ex