METHOD OF MANUFACTURING CHLORINE-FREE POTASSIUM MINERAL FERTILIZERS Russian patent published in 2003 - IPC

FIELD: mineral fertilizer production. SUBSTANCE: manufacture of chlorine-free potassium mineral fertilizers involves using at least two fixed-bed cationexchange columns. Through the first column, potassium chloride solution is passed to convert cationite in the ionic form with an auxiliary component into potassium form. Simultaneously, chlorine-free solution of the mentioned auxiliary component is passed through the second column to convert potassium salt of cationite into auxiliary component form. Cationite is selected such as to ensure its selectivity for the auxiliary component higher than that for potassium and concentration of chlorine-free salt of auxiliary component in the solution utilized is selected higher than concentration of saturated solution of chlorine-free potassium salt. At outlets of the first and second columns, supersaturated solution of chlorine-free potassium salt is alternately obtained, which is then kept to allow crystallization of this potassium salt. Solutions, after separation of precipitated salt in each cycle, are combined with solution of chlorine-free salt of auxiliary component prior to be passed through each of the columns. EFFECT: avoided formation of waste, enabled use potassium production waste and waste waters, and reduced potassium fertilizer cost because production of solid fertilizers. 7 cl, 3 dwg, 1 tbl, 4 ex