Experimental Study On Expanding Titanium Dioxide Production By Calcium Vapor Reduction Titanium Dioxide

Metallic titanium is an indispensable key material for the development of national economy. Developing new low-cost production processes of titanium or titanium powders have been very significant for faster and sustainable development of titanium industry. On the basis of predecessors’ small laboratory experiment, the kilo-scale preparation of titanium powders from TiO2by calcium vapor reduction has been researched in this paper.Thermodynamic calculation shows that TiO2and other impurities, such as ZrO2, NbO, K2O, SiO2, P2O5, Fe2O3in titanium pigment are respectively reduced to Ti, Zr, Nb, K, Si, P and Fe in the process of reduction. Various reactors were designed and the expended experiments were carried out. The results discover the type Ⅳ reactor is effective and operable. The acid leaching research of reduction products in expanding experiments found that the leaching rate of Ti decreases with deceasing temperature, n(HCl/CaO) and particle size but increasing liquid-to-solid ratio, and the leaching rate of calcium increases with increasing temperature, n(HCl/CaO), liquid-to-solid ratio but decreasing particle size. By orthogonal and single factor experiment methods, the best technological parameters are determined as follows:Stirring speed500r/min, temperature25℃, molar ratio of acid and calcium oxide2.25:1, the particle size less than45μm, liquid-to-solid ratio30:1, acid leaching time15min.Under the conditions of reducing temperature1050℃and holding time24h, titanium powders, with hexagonal system structure and particle size10～45microns, were prepared. And the powders compositions are as follows:Ti:99.6%, O3800ppm, Ca565ppm, N43ppm, P37ppm, Fe657ppm, Zr293ppm, Si1105ppm and Cl less than20ppm, meeting the TF-0requirements of YS/T654-2007titanium powders standard.