METHOD OF PRODUCTION OF PHOSPHORUS-POTASSIUM FERTILIZER Russian patent published in 2001 - IPC

FIELD: inorganic chemistry, fertilizers. SUBSTANCE: invention relates to production of complex phosphorus-potassium fertilizers using slimes formed in treatment of wet-process phosphoric acid. Method of production of phosphorus-potassium fertilizers involves mixing solid phosphorus-containing component with acidic solution containing phosphoric and sulfuric acids, treatment of pulp with calcium-containing reagent, mixing pulp with potassium reagent, granulation and drying the ready product. Phosphorus-containing slimes with high content of fluoride are used as solid phosphorus- -containing component and potassium reagent is fed for two stages: firstly, to stage of mixing slime with acidic reagent potassium carbonate and/or potassium sulfate is fed to value pH of pulp 1.7-3.6 and then after treatment of pulp with calcium-containing reagent it is mixed with remained part of potassium carbonate and/or potassium chloride. Wastes after treatment of wet-process phosphoric acid containing 15-23% of P₂O₅, 4-8% of F and 40-50% of H₂O are used as phosphorus- -containing slimes with high content of fluoride. Method ensures to process phosphorus-containing slimes with high content of fluoride to obtain phosphorus-potassium fertilizer of high quality. EFFECT: improved method of production. 2 cl, 1 tbl