Thermal Treatment of Titania Slag under Oxidation-Reduction Conditions

T.A.I. Lasheen1 and M.E.H. Shalabi2

1Nuclear Materials Authority, P.O.Box 530 El Maadi, Cairo, Egypt

2Central Metallurgical Research and Development Institute, Cairo, Egypt

Abstract

The present work provides a method for beneficiating of an Egyptian titanium slag by a thermal oxidation and reduction in a controlled gas atmosphere to obtain leachable slag suitable for use as a feed material in the production of TiO2 by chlorination process. The mechanism of that process has been studied and the proposed reactions are presented. The effect of oxidation on the enrichment of titanium into rutile phase by blowing oxygen into the slag was studied at relatively high temperatures (900-1100C) for different times (30-90 min). Heating of a fully divided slag under oxidizing conditions resulted in a major portion of iron in the ferric state Fe3+ and titanium species in Ti4+ state. The results demonstrate that through oxidation, the content of pseudobrookite and rutile phases increase. Reducing of the pre-oxidized slag was carried out using hydrogen gas at 800C for different period of times to convert the major portion of iron in ferric state Fe3+ to ferrous state Fe2+. As a result of these treatments most of titania phases were converted into rutile. Thereafter, the reactive ore was treated with aqueous HCl acid then sodium hydroxide solutions to leach impurities to obtain a beneficiated product with an increased TiO2 content.