Enrichment of TiO2 in titania slag obtained from carbothermal smelting of ilmenite

• Carbothermal smelting enabled efficient separation of titania-rich slag and metallic iron. • Titania slag consists of TiO 2 and pseudobrookite (Fe 2 TiO 5 ) phases. • Subsequent acid leaching of titania slag yielded ∼95 % TiO 2 grade. • Recovered metallic iron contains ∼94 % Fe. • TiC formed in minor quantities within the metallic iron. Ilmenite (FeO·TiO 2 or FeTiO 3 ) contains 40–65 % TiO 2 depending on its geological distribution. Since India is rich in Ilmenite resources with reserves of around 687.57 million tons spread over the peninsular coastal belt, an attempt has been made to utilize it to produce high-grade titania slag. Ilmenite concentrate with ∼54 wt% TiO 2 was subjected to carbothermal smelting in an arc furnace. Titania slag (∼88 wt% TiO 2 ) and pig iron were obtained as products of carbothermal smelting. The smelting products were characterized in detail. XRD of titania slag revealed the presence of Fe 2 TiO 5 and TiO 2 as major phases, along with small percentage of iron. The pig iron contained ∼93.69 wt% iron and 2.78 wt% carbon with traces of sulfur and phosphorous, it can suitably be further used to produce different grades of ductile cast iron. To enhance the percentage of TiO 2 in titania slag, two upgradation approaches, namely, wet magnetic separation and chemical leaching of titania slag, were employed. Non-magnetic fraction was enriched with ∼91.73 wt% TiO 2 , whereas magnetic Fe particles were reported in the magnetic fraction containing ∼74.76 wt% Fe. Furthermore, upgradation of TiO 2 up to 94.72 wt% was achieved by selective acid leaching (12 M HCl) of titania slag. The leaching parameters, such as time and temperature, were varied (both in static and dynamic conditions) to assess the leaching rate and activation energy. The activation energies of 14.56 kJ/mol and 8.14 kJ/mol were calculated for Fe leaching from titania slag in static and dynamic leaching conditions, respectively.