Effect of carbon on the beneficiation of OSCOM ilmenite by carbonitrothermy

•Beneficiating ilmenite using carbon in the presence of nitrogen is demonstrated.•Studies were done with various forms of carbon. The study shows that carbon type does not alter the overall beneficiation reaction.•Ilmenite was reduced to TiN and Fe. Fe was removed by HCl treatment yielding pure TiN phase. Ilmenite (FeO·TiO2) and rutile (TiO2) are well-known minerals for titanium. Ilmenite is far more abundant than rutile in nature. However, ilmenite contains iron oxides and the TiO2 content of ilmenite is considerably less than rutile. Hence it is necessary to upgrade (enhance TiO2 content) Ilmenite by removing iron before it could be processed for recovery of pure TiO2. Compared to the other grades of ilmenite in India, OSCOM grade from Chatrapur, Orissa has the lowest content of TiO2. Hence beneficiation of such a grade of ilmenite is highly challenging and cost intensive. The present work explores the possibility of beneficiation of ilmenite by a carbonitrothermic process using three different forms of carbon namely, petroleum coke, carbon black and graphite. The thermogravimetry results of carbonitrothermic reduction of ilmenite and rutile and the residue analysis are presented in detail to determine whether the form of carbon has any role in this beneficiation process.