Upgrading a Ti-slag by a roast-leach process

A roast-acid leaching process has been developed for upgrading titanium slag with high Ca and Mg to a synthetic rutile. The optimized roasting conditions used a Na2CO3 to slag weight ratio of 3:7 at 850 °C–900 °C for 1 h. The roasted product was mainly comprised of sodium titanate, sodium ferrite and Na–Fe–Ti–O and Na–Mg–Ti–O phases. The impurities associated with the roasted product were leached in water and dilute sulfuric acid solution, while the soluble titanium precipitated as hydrated TiO2. The hydrated TiO2 was transformed into a synthetic rutile, assaying over 95% TiO2 and 0.82% MgO + CaO, by calcination.