METHOD OF PRODUCING PHOSPHATE-POTASH FERTILIZER Russian patent published in 1999 - IPC

FIELD: production of complex phosphate-potash fertilizers. SUBSTANCE: method includes decomposition of phosphate raw material with sulfuric acid or its mixture with phosphoric acid; mixing of phosphoric acid pulp with potash reagent; granulation and drying of ready-made product. Pulp is neutralized with alkali potash-containing reagent with pH 3.1-7.5. When number of process stages is reduced, pulp acidity is reduced up to 0-0.9% of free P₂O₅, and content of water-soluble fluorine in ready-made product, up to 0.1-0.2%, while ratio P₂O₅:K₂O increases up to 1:(0.5-1.32). EFFECT: higher efficiency. 1 tbl