Role of aluminum salt on thermal hydrolysis of titanyl sulfuric–chloric mixture acid solution

Abstract

To make use of scrap perovskite titanium slag to produce metatitanic acid, a new method based on the high efficiency decomposition ability of sulfuric–chloric mixture acid (SCMA) has been proposed. Because Al is one of the most common elements existing in its raw state, Al3+ has become the main impurity in titanium solutions after decomposition, which affects the performance of related products. Consequently, the role of Al on the thermal hydrolysis of Ti in the SCMA solution was investigated in this study. With the addition of Al3+, a lower hydrolysis ratio was obtained at a low reaction temperature (130 °C). Moreover, the particles of metatitanic acid displayed a ball-shaped morphology and narrow particle distribution with a D50 of 1.4–2.0 μm. According to the crystal structures of Al3+, it is presumed that the priority order of ligand is SO42−>H2O>Cl−. The addition of Al3+ increases the growth rate of the a- and b-axes but reduces the growth rate of the c-axis. The results presented here confirm the influence of Al3+ in the control of nucleation and growth process during the hydrolysis to achieve qualified metatitanic acid products.

Keywords

• Al3+ impurity
• Hydrolysis
• Sulfuric–chloric mixture acid
• Particle size
• Grain size
• Metatitanic acid