METHOD FOR EXTRACTION OF MAGNESIUM-AMMONIUM-PHOSPHATE FROM WASTEWATER Russian patent published in 2022 - IPC C02F1/58 

FIELD: chemical technologies.

SUBSTANCE: invention relates to chemical technologies, and in particular to methods for extracting magnesium ammonium phosphate from agro-industrial or domestic wastewater. The method includes supplying wastewater to a heated reactor. To maintain a pH of 8.0-10.0, a correction solution of sodium hydroxide is added to the reactor. Wastewater is mixed in a reactor with a magnesium-containing solution obtained from bischofite or an alternative source of magnesium - magnesium hydrosilicate and a solution of hydrochloric or sulfuric acid. At the same time, these solutions are introduced into wastewater continuously to ensure a molar ratio equal to 0.9-1.1 Mg²⁺ : 1,0-1,6NH₄⁺ : 1,0-1,1 PO₄^3-. Chemical precipitation of magnesium ammonium phosphate is carried out at a temperature of 15 to 30°C with the addition of a seed - treated wastewater filtrate containing finely dispersed magnesium ammonium phosphate.

EFFECT: extraction of magnesium-ammonium-phosphate from agro-industrial wastewater in the form of a large, easily filterable precipitate, which can be used as a nitrogen-phosphorus fertilizer, is provided.

3 cl, 1 tbl, 4 ex