Synthesis of TiO2 from the Low-Grade Ilmenite Using the Mechanical Activation and Reductive Pressure Leaching in Low-Concentration H2SO4

The synthesis of TiO2 from the low-grade Indian ilmenite feedstock using the reductive pressure leaching process route has been presented in this work. Results show that the Ti and Fe dissolution efficiency has improved from 50% each to 74% and 78%, respectively, with the addition of 10 g center dot L-1 urea in 7.5 mol center dot L-1 H2SO4 at optimized leaching conditions. After the mechanical activation of ilmenite ore for 45 min, the Fe and Ti dissolution increased further to 93% and 90%, respectively. The leaching kinetics of both Fe and Ti are controlled by the solid-liquid chemical reaction mechanism in the presence and absence of reductant. XRD and SEM-EDX results show that an amorphous anatase grade TiO2 with 95% purity is obtained as the final product after crystallization, hydrolysis, and calcination steps. The total extraction efficiency of TiO2 is found to be 85%.