Leaching studies of alkali roasted bomarilmenite and anatase during the processing of synthetic rutile

• This paper highlights an alternative route for the processing of lean quality of titaniferous ores with rare earths dispersed throughout the grains.
• An insight into the physical chemistry of leaching of alkali roasted Bomar ilmenite or anatase is explained with results obtained from experiments, Eh–pH diagram, XRD, SEM and EDX.
• The alkali roasting provides a better way to remove rare earth oxide, unattacked by the processing steps.
• Better iron and sodium oxide removal was observed when NH4Cl + CH3OH + acetic acid was used as the leaching medium compared to HCl acid.
• The particle size of the processed material was comparable to the size required for further chlorination in Fluidised Bed Chlorination Reactor (FBCR).

The leaching of sodium (Na+) and Fe2 +,3 +, ions from the soda-ash roasted ilmenite (FeO–TiO2) or anatase minerals has been examined as a chemical method for beneficiating titani-ferous minerals for the production of pigment grade TiO2. In the leaching step, the roles of catalytic aeration, dilute concentrations of organic liquids (methanol) in the range of 0.5% (v/v) in 1.5% (w/v) ammonium chloride are explained. The results of leaching experiments are also compared in the presence of inorganic acid with that of ammonium salt and acetic acid for retaining the particle size. The role of pH in the removal of sodium and iron ion is also explained based on Eh–pH diagram. The paper also explains the selective separation of rare earth oxides during the processing of synthetic rutile. The data obtained at each step of processing is explained and interpreted on the basis of results obtained through XRD, SEM and EDX. Rare earth oxides are separated unattacked by the processing steps.