METHOD OF PROCESSING PHOSPHOGYPSUM FOR PHOSPHOROUS FERTILIZER Russian patent published in 2019 - IPC C05B11/00 C05B13/06 

FIELD: agriculture.

SUBSTANCE: method of processing phosphogypsum to phosphate fertilizer involves the conversion of phosphogypsum followed by separation of the precipitate from the solution, and before the conversion of phosphogypsum pre-prepare a solution of sodium carbonate with a concentration of 152–156 g/l of Na₂O and solution temperature 60–70 °C the prepared solution of sodium carbonate the conversion of phosphogypsum is carried out at a temperature of 75–80 °C, with a ratio, wt.%: phosphogypsum, in terms of dry, 24.0–25.0, sodium carbonate solution 75.0–76.0, resulting in calcium carbonate, a solution of sodium sulfate, calcium carbonate is washed and sent to neutralize phosphoric acid with a content of 35.0–37.0 wt. % P₂O₅, upon completion of the process of neutralization of phosphoric acid, a suspension of phosphate fertilizer with a humidity of 57–60 % is obtained, which is sent for drying and granulation.

EFFECT: invention allows to expand the arsenal of methods of processing phosphogypsum by creating a method of processing phosphogypsum with obtaining phosphate fertilizer with a high P₂O₅ content in digestible and water soluble form.

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