Preparation of Hydrated TiO(2) Particles by Hydrothermal Hydrolysis of Mg/Al-Bearing TiOSO(4) Solution

As the byproduct in the smelting process of vanadium titano-magnetite, titanium-bearing blast furnace slag (TBFS) can be converted to a titanyl sulfate (TiOSO(4)) solution containing MgSO(4) and Al(2)(SO(4))(3) impurities via dissociation by concentrated H(2)SO(4) (80–95%) at 80–200 °C, followed by leaching with H(2)O at 60–85 °C. In this study, hydrated TiO(2) was prepared by hydrothermal hydrolysis of a Mg/Al-bearing TiOSO(4) solution at 120 °C and the hydrolysis law was investigated. The experimental results indicate that MgSO(4) and Al(2)(SO(4))(3) accelerated the hydrolysis and significantly affected the particle size (increasing the primary agglomerate size from 40 to 140 nm) and dispersion (reducing the aggregate size from 12.4 to 1.5 μm) of hydrated TiO(2). A thermodynamic equilibrium calculation showed TiOSO(4) existed as TiO(2+) and SO(4)(2−) in the solution, and MgSO(4) and Al(2)(SO(4))(3) led to little change of [TiO(2+)], but an obvious decrease of [H(+)], which favored the hydrolysis process. At the same time, the coordination–dissociation mechanism of SO(4)(2−) and Al(SO(4))(2)(−) facilitated the lap bonding of Ti-O-Ti, promoting the growth of hydrated TiO(2) synergistically.