METHOD OF PREPARING ATMOSPHERE-RESISTANT PIGMENT FROM SPHENE CONCENTRATE Russian patent published in 2001 - IPC

FIELD: varnish-and-paint industry. SUBSTANCE: sphene concentrate is subjected to dry crushing and 15-30% of modifier consisting of aluminum phosphate and silicic acid gel is added to crushed material. Resulting paste is dispersed for 2-5 h and than thermally treated at 50 to 500 C. Suspension of modifier is obtained by adding nepheline to phosphoric acid solution (concentration 10-15% on conversion to P₂O₅) to achieve pH 1.5-3.5. Pigment is characterized by high degree of whiteness. EFFECT: increased resistance to paint splitting. 2 cl, 2 tbl, 3 ex