METHOD OF PREPARING PHOSPHORUS-CONTAINING MINERAL FERTILIZER Russian patent published in 2002 - IPC

FIELD: agriculture. SUBSTANCE: described are methods of preparing phosphate fertilizers having high content of plant assimilable P₂O₅ from phosphate raw material such as apatite or phosphorite in which P₂O₅ is present in form slightly assimilable by plants. Method comprises separately grinding phosphorus-containing raw material and mineral additive and subsequently mixing thereof. Grinding of phosphorus-containing raw material is carried out in highly loaded mills till 5-25% of amorphization is attained, and mineral additive is natural zeolite, and starting components are mixed at 1:(2-5)wt parts ratio, respectively. In other to grind phosphorus-containing raw material, use is made of continuous or centrifuged planetary mills. Natural zeolite is clinoptylol-containing tuff ground to particle size of not greater than 0.2 mm. Method makes it possible to improve quality of phosphorus-containing mineral fertilizer due to increasing citric soluble P₂O₅ form by effectively using natural phosphate raw material and also reducing power intensiveness of process. EFFECT: more efficient preparation method. 4 cl, 1 tbl