Study on coal-based solid state reduction of Panzhihua ilmenite

Abstract

The coal-based solid-state reduction of ilmenite is a fundamental and common pretreatment process in the titanium industry. Investigating the mechanism of coal-based solid-state reduction of ilmenite elucidates Fe/Ti separation and phase transformation, providing theoretical guidance for preparing Ti-rich materials from reduced ilmenite, optimizing processes, and enhancing TiO₂ grade, with significant implications. Firstly, the pre-oxidation experiment of Panzhihua ilmenite was carried out, and then the solid state reduction experiment and pre-oxidation of Ilmenite was carried out by using bituminous coal at 800 ℃−1150 ℃, and the relevant characterization analysis of the test samples was carried out. The results show that the pre-oxidation treatment can destroy the compact structure of ilmenite, which is beneficial to the reduction of ilmenite. Many pores are produced in the reduced ilmenite due to the formation of many metallic iron. The enrichment of MgO and MnO in the reduction process of ilmenite hinders the further reduction of FeO; during the ilmenite reduction, the honeycomb-like rutile (TiO₂) phase develops, and the reduction temperature has a significant effect on the content of rutile phase. When the reduction temperature does not exceed 1000 ℃, the content of rutile increases with reduction temperature increasing. However, when the reduction temperature exceeds 1000 ℃, rutile transforms into low-valent titanium oxide.