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

Rutile TiO is widely applied as the raw material to produce titanium dioxide and titanium sponge, whereas the Cr (III) and V (V) impurities in rutile TiO 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 TiO 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 TiO 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 TiO was produced by the leaching residue calcined at 1323.15 K with a duration time of 120 min, with 85.56 % of TiO grade. The work highlights the feasibility of synchronously preparing rutile TiO and removing hazardous Cr (III) and V (V) impurities from titanium slag using sodium carbonate decomposition.