The dissolution of iron in the hydrochloric acid leach of titania slag obtained from plasma melt separation of metalized ilmenite

This work is concerned with the determination of leaching characteristics of titania rich slag by hydrochloric acid. This can be considered as an alternative to selective iron dissolution and insolubilization of TiO2 in the form of synthetic rutile. The relevant criteria for titania slag leaching in hydrochloric acid are studied, including the acid concentration, experimental parameters and solid/liquid ratio, which controls the acid/slag molar ratio as well as effect of reduction. Ilmenite or metalized ilmenite, when smelted/melted under thermal plasma gives titania rich slag and iron metal as products. Preparation of upgraded feedstock from titania slag depends on leachability of it by mineral acids. The data reveals that the optimum conditions involve working with 6 M acid with a solid/liquid ratio of 1/20 at room temperature for 1 hour, using slag ground to less than 74 μm. The results will have significant impact on production of upgraded feed stock.

Research highlights
► Leachability of titania rich slag produced from melt separation of the metallized ilmenite.
► Leachability depends on thermal plasma parameters, heat treatment of the slag and additives.
► Acid concentration and duration of leaching will have significant impact on production of upgraded feed stock from titania rich slag.
► The upgraded feed stock, equivalent to synthetic rutile is considered as the feed material in the pigment industry.