METHOD OF PREPARING WOLLASTONITE Russian patent published in 1997 - IPC

FIELD: manufacture of friction materials, ceramics, paints, plastic materials, and industrial rubber products. SUBSTANCE: claimed method comprises melting mixture of phosphate fertilizer production waste and aluminium lucride or quartz sand in the presence of sulfur, carbon, zinc sulfate, calcium phosphate at ratio of CaO/SiO₂ of 0.9:1; C/SiO₂ of 0.10-0.14:1; S/SiO₂ of 0.1-0.2:1; P₂O₅/SiO₂ of 0.05-0.06:1; ZnO/SiO₂ of 0.02-0.04:1. Melt is sharply cooled and granules are heat treated in reducing medium at 830-920 C for 80-90 min. The claimed method makes it possible to obtain needle-like wollastonite with needle length of 250-300 mcm, characteristic l/d ratio of greater than 30 and yield of 96-97%. EFFECT: more efficient preparation method. 2 cl, 6 tbl