| abstract |
A TITANIUM DIOXIDE RUTILE PIGMENT OF GOOD BRIGHTNESS, COLOUR, AND OTHER FAVOURABLE PROPERTIES IS MADE BY ADDING A RUTILE SEED TO A TITANIUM SULPHATE SOLUTION, HYDROLYSING THE TITANIUM SULPHATE TO A HYDROUS TITANIUM DIOXIDE GEL, ADDING FURTHER RUTILE SEED (PREFERABLY PREPARED IN A DIFFERENT WAY), AN ALKALI METAL COMPOUND, A ZINC COMPOUND, AND AN UNUSUALLY HIGH PROPORTION OF PHOSPHORIC ACID OR A PHOSPHATE, DRYING THE GEL CONTAINING THE ADDITIVES, AND CALCINING IT, PREFERABLY AT ABOUT 1000*C. |