Soda ash roasting of titania slag product from Rosetta ilmenite

A soda ash roasting process for upgrading titania slag product of Rosetta ilmenite to a high grade titanium dioxide (TiO2) is presented. The roasting process was carried out at moderate to high temperatures to yield a reaction product that would be easily decomposed by subsequent leaching procedures. Factors affecting the roasting process; namely the soda ash ratio to the slag material, the roasting time and temperature were studied. The optimised conditions used a Na2CO3 to slag ratio of 0.55:1 at a roasting temperature of 850 °C for 0.5 h duration period. The impurities associated with the roasted slag were subjected to leaching with water and dilute hydrochloric acid solution leaving synthetic rutile (TiO2) as insoluble residue. To improve the quality of the synthetic rutile, an alkaline leaching step was added to remove the excess silica present in the treated titania slag. This method is capable of producing high purity synthetic rutile assaying about 97% TiO2.