METHOD FOR EXTRACTION OF MAGNESIUM-AMMONIUM-PHOSPHATE FROM WASTEWATER Russian patent published in 2023 - IPC C02F1/58 

FIELD: chemical technologies.

SUBSTANCE: invention relates to methods for extracting magnesium ammonium phosphate from wastewater containing ammonium nitrogen and phosphate ions to obtain a product (struvite) suitable for use as a nitrogen-phosphorus fertilizer. The invention relates to methods for extracting magnesium ammonium phosphate from wastewater containing ammonium nitrogen and phosphate ions. A correction solution of sodium or ammonium hydroxide is added to the reactor with waste water to maintain pH at 8.0–9.0. The adjusted solution is mixed in a reactor with a solution of bischofite or a pre-prepared acid extract from magnesium hydrosilicate. Additionally, crushed diatomite or silicon-containing leaching residue of magnesium hydrosilicate — silica and silica sol — are added. The resulting suspension is divided into streams with small and large sediment particles. The fine precipitate is returned to the reactor for coarsening the crystals. Then the coarse precipitated magnesium ammonium phosphate is filtered and the purified water is removed.

EFFECT: obtaining a cheaper and less energy-consuming complex nitrogen-phosphorus fertilizer of prolonged action in the form of magnesium-ammonium-phosphate with a controlled release of nutrients in the soil, which makes it possible to use the fertilizer for various types of soils.

3 cl, 1 tbl, 4 ex