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

Abstract

Ilmenite (FeO & centerdot;TiO2 or FeTiO3) contains 40-65 % TiO2 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 similar to 54 wt% TiO2 was subjected to carbothermal smelting in an arc furnace. Titania slag (similar to 88 wt% TiO2) 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 Fe2TiO5 and TiO2 as major phases, along with small percentage of iron. The pig iron contained similar to 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 TiO2 in titania slag, two upgradation approaches, namely, wet magnetic separation and chemical leaching of titania slag, were employed. Non-magnetic fraction was enriched with similar to 91.73 wt% TiO2, whereas magnetic Fe particles were reported in the magnetic fraction containing similar to 74.76 wt% Fe. Furthermore, upgradation of TiO2 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.