Utilization of Roast-Reduced Ilmenite Leach Liquor for Ferrous Chloride Production by Hydrothermal Process

Abstract

Ilmenite is the most abundant mineral for the extraction of titanium. It contains more than 50% TiO2 along with iron, silica and alumina. The spinel structure of ilmenite (FeO·TiO2) is such that iron is bound in the lattice of TiO2 matrix. To remove iron from the ilmenite is a major task for process metallurgists. Various processes have been applied to remove this iron. One of them is reduction and leaching. The carbon containing pellets and environment of Jhama coal reduces the iron oxide to metallic state. This metallic iron is then leached in dilute hydrochloric acid (20% vol) and a greenish color leach liquor is obtained. The pH of the leach liquor solution is found to be 0.31. This leach liquor contains hydrochloric acid and iron as ferrous chloride. These acid and solid masses were separated by hydrothermal process in the present investigation. The residue containing ferrous chloride was characterized with the help of XRD and EPMA. During the experiment it was found that complete separation of HCl and FeCl2 is feasible. The final pH of separated HCl is found to be 1.66 and it is suitable for reuse in the leaching of reduced ilmenite and the process makes a loop. The purity of ferrous chloride is in line with commercial grade which is a saleable product.