Acid leaching of ilmenite decomposed by KOH

The effects of reaction time, KOH concentration, alkali-to-ilmenite mass ratios and reaction temperature on titanium decomposition were investigated. Minor amounts of titanium and iron were leached (less than 2%) from the decomposed ilmenite ore in the alkaline KOH solution. After alkaline treatment, the ilmenite paste was leached to extract iron, titanium, chromium and vanadium by adding sulfuric acid, hydrochloric acid or oxalic acid. The significant effects of reaction time, acid concentration, acid-to-ilmenite mass ratios and reaction temperature on the leaching were studied for each acid. About 93%, 92% and 89% of titanium could be leached from the alkaline treated ilmenite paste, under the optimal conditions by oxalic acid, hydrochloric acid and sulfuric acid, respectively.