METHOD OF SUPERFICIAL PROCESSION OF PIGMENT TITANIUM DIOXIDE Russian patent published in 2008 - IPC C09C1/36 C09C3/06 C01G23/47 

FIELD: chemistry.

SUBSTANCE: invention can be used in lacquer-paint industry, in production of plastics, paper and other branches. Method of superficial procession of pigment titanium dioxide includes dechlorisation of titanium dioxide, wet milling and hydro-classification of titanium dioxide suspension, superficial procession of titanium dioxide, filtration, washing of titanium dioxide paste, its procession with organic compound, drying and microgrinding. Dechlorisation process is carried out at temperature of 50-60°C by combined dispersion of titanium dioxide in water and reduction of admixture chlorine in TiO₂ with sodium hypophosphite in the amount twice exceeding content of chlorine in titanium dioxide, with further neutralisation of suspension with solution of sodium silicate to pH 6.5-7.0 and filtration. Suspension stabilisation before hydro-classification is carried out with solution of sodium silicate to pH of suspension 9.0-9.5 at temperature of 50-60°C. Superficial procession of fine fraction of suspension TiO₂ is carried out at temperature of 60-70°C with compounds of titanium and aluminium using 1.0% weight TiO₂ from solution of titanium tetrachloride, 2.5% weight Al₂O₃ from solution of sodium aluminate and 1.2-1.5% weight Al₂O₃ from solution of aluminium chloride. Processed suspension is filtered; paste is repulped in water to remove water-soluble substances; suspension is filtered. Prior to drying TiO₂ paste is processed with organic compounds in The form of alkyl dioxyethylene in amount of 0.3-0.6% weight to TiO₂, dried and microground.

EFFECT: increased indices of titanium dioxide, such as output of fine fraction of suspension TiO₂ on hydro-classification, reduction of content of water-soluble substances in pigment, improvement of dispersibility in organic binders and gloss in akril paint and an increase in atmosphere-resistance.

2 cl, 5 ex, 3 tbl