Simultaneous removal of Cr(III) and V(V) and enhanced synthesis of high-grade rutile TiO2 based on sodium carbonate decomposition.

Rutile TiO2 is widely applied as the raw material to produce titanium dioxide and titanium sponge, whereas the Cr (III) and V (V) impurities in rutile TiO2 significantly affect the performance of related products. In the present work, the sodium carbonate decomposition treatment on Panzhihua titanium slag was attempted, to improve the preparation process of rutile TiO2 with high crystallinity and simultaneously reduce the chromium (Cr) and vanadium (V) content as hazardous elements. Effects of sodium carbonate decomposition treatment on the crystal composition, microstructure of rutile TiO2 were determined using XRD, SEM and Raman characterization. The recovery of Cr(III) and V(V) was achieved through leaching the roasted titanium slag by dilute sulfuric acid, with the chromium and vanadium content in the residue decreasing up to 0.03 % and 0.04 %, respectively, followed by the final product rutile TiO2 was produced by the leaching residue calcined at 1323.15 K with a duration time of 120 min, with 85.56 % of TiO2 grade. The work highlights the feasibility of synchronously preparing rutile TiO2 and removing hazardous Cr (III) and V (V) impurities from titanium slag using sodium carbonate decomposition.