Synthesis of rutile from high titania slag by pyrometallurgical route

A new technique was developed for the conversion of high titania slag, containing 70%-75% TiO2 and with MgO, FeO, CaO, Al2O3 and SiO2 as main impurities, into a synthetic rutile, 90%-95% TiO2, which satisfies the requirements for fluidizing chlorination process with respect to impurity contents. After a pre-oxidation at around 1 042 °C and a heat-treatment above 1 510 °C, the Ti components in high titania slag can be enriched into the rutile phase which can precipitate and grow, and can be separated with dilute hydrochloric and sulfuric acid, respectively. The results show that the average crystal size of rutile phase is over 25 μm, and the synthetic rutile containing more than 95% TiO2 can be produced by selective leaching.