NATURAL PHOSPHATE DEFLUORINATION METHOD Russian patent published in 2003 - IPC

FIELD: inorganic compounds technology. SUBSTANCE: invention relates to defluorinated calcium phosphates used as carriers of high-assimilated (citrate- soluble) phosphorus and calcium forms in manufacture of cattle and poultry feeds. Method envisages mixing naturally occurring phosphates with phosphoric acid and sodium silicate with silica modulus 0.35-0.95, which is added in amounts ensuring sodium silicate-to-calcium oxide weight ratio within a range of 0.2-0.3. Resulting mixture is fired in tube kiln at 1330-1380 C. Final product contains 92.5-100% citratesoluble form of phosphorus pentoxide based on its total weight and 0.014-0.045% fluorine. Weight ratio of P₂O₅ coming with phosphoric acid to citrate-soluble P₂O₅ in product is 0.215- 0.220. EFFECT: stabilized equipment functioning. 1 tbl, 5 ex