METHOD OF AGGLOMERATION AND GRANULATION OF PHOSPHATE RAW MATERIAL Russian patent published in 2001 - IPC

FIELD: mining industry. SUBSTANCE: invention relates to preparing fine natural- origin zirconium-containing phosphate raw material used in production of yellow phosphorus. Raw material is rolled in presence of complex correcting additive possessing simultaneously fluxing and binding capacities and containing following components, wt %: phosphoric oxide 30-40, sodium oxide 18-25, calcium oxide 10-14, magnesium oxide 0.5-8.0, aluminum oxide 2-3, ferric oxide 2-3, potassium oxide 0.2-3, silicon dioxide 0.3-1.0, fluoride 5-17, crystallization water - the balance. pH value of 1% aqueous suspension of additive ranges from 5 to 6.5. Additive is used in amount of 1 wt part per 3-8 wt parts of phosphate material. Rolled material is dried and resulting pellets are fired at 1150-1350 C. Additive can be prepared by neutralizing extraction phosphoric acid by soda ash or caustic soda to give Na₂O/P₂O₅ ratio providing pH value ranging from 4 to 5, after which suspension is separated into purified alkaline solution and solid phase used as complex correcting additive. The latter is advantageously utilized with 40-55% of hygroscopic water. EFFECT: enabled firing of zirconium-containing phosphate raw material at 1150-1350 C leading to yield of product fractions 95-96% and increased strength of final product to 19024 MPa. 3 cl, 2 tbl, 2 ex