METHOD FOR UTILIZATION OF AMMONIA FROM SCRUBBER WATER TO OBTAIN STRUVITE Russian patent published in 2023 - IPC C02F1/58 

FIELD: chemistry.

SUBSTANCE: invention relates to a chemical technology of isolation and utilization of ammonia nitrogen from an aqueous phase of wet scrubbers to obtain struvite; it can be used in chemical, petrochemical, metallurgy, coke chemical industry, as well as municipal and agricultural facilities. A method for utilization of ammonia from scrubber water after absorption of ammonia with an acid solution to obtain struvite includes introduction of magnesium ions in the form of bischofite and, if necessary, phosphate ions in the form of sodium or potassium hydrophosphates. Before precipitation of struvite, a molar ratio of Mg²⁺:NH₄⁺:PO₄^3- ions, equal to (1.0-1.2):1:1, is set in water, and pH of the solution is maintained at a level not higher than 4.6±0.3. Subsequent neutralization is carried out with a sodium hydroxide solution of 2-6 M until reaching a pH value of 8.5-9.0 by infusion of alkali for no more than 45 seconds.

EFFECT: invention allows for an increase in a degree of extraction of NH₄⁺ ions from scrubber water of a different composition without use, during precipitation, of significant excess of Mg²⁺ and/or PO₄^3- ions in scrubber water against their stoichiometric amount in a composition of struvite.

2 cl, 1 dwg, 1 tbl, 6 ex