Rutile TiO₂ Production by Inductive Hydrolysis of Low Concentration Titaniferous Solution with Seed Crystals Prepared by Microwave

Low concentration of titaniferous solution(160 g/L) was inductively hydrolyzed with seed crystals prepared under microwave,which has a favorable energy-saving effect on TiO₂ production by sulfuric acid process.The calcination parameters of metatitanic acid were determined by TG and SEM analysis.The results show that the metatitanic acid,obtained by inductive hydrolysis with seed crystals prepared under microwave,possesses a high crystalline transfer activity that it can completely convert to rutile crystals by calcination at 850℃ for 30 min without any crystalline transfer additive. Furthermore,the prepared seed crystals can be stored for a long time making easy industrial application. The effects of salt treatment and calcination parameters on the pigmentary properties of TiO₂ were also investigated. It is evidenced that increasing the phosphorus content is beneficial to improve whiteness of the rutile TiO₂ and it can be significantly reduced by agglomeration of the particles at too low concentration of potassium? content.Rutile TiO₂ with higher whiteness and more uniform size distribution(200~350 nm) is obtained under the optimum salt treatment parameters of calcination at 900℃ for 90 min with 0.55% K₂O and 0.1% P₂O₅ added.