METHOD FOR PRODUCTION OF HEAT-RESISTANT CERAMIC PIGMENTS Russian patent published in 1995 - IPC

FIELD: production of heat-resistant pigments. SUBSTANCE: solutions of zirconium chlorides or nitrates and chromophore metal at molar ratio 1: 0.01-0.03 as calculated for salts are mixed with finely dispersed silicium oxide, Reynolds number being Re=2·10⁴-5·10⁴. Thus prepared suspension is treated by aqueous solution of ammonia to pH 8-9. Precipitate is dried with the help of filter, dried and calcined in two steps. The first step of calcination is carried out at 700-900 C, it is followed by cooling and by adding mineralizing agent. The second step of calcination takes place by heating to 1100-1300 at rate 5-10 C/min. EFFECT: decreases size of pigment particles, increases intensity of bright yellow color, decreases quantity of chromophore additive. 2 cl, 1 tbl