A new process was provided for decomposition of ilmenite by concentrated KOH solution under atmospheric pressure. The significant effects of reaction temperature, KOH concentration, stirring speed, particle size, and alkali-to-ilmenite mass ratios on titanium extraction were studied. The temperature and initial particle size showed significant influence on titanium extraction. The experimental data of the extraction rates under the relevant operating variables were well interpreted with the shrinking core model under chemically controlled process. The apparent activation energy of the reaction was evaluated using the Arrhenius expression. Approximately 80-85% of the titanium could be leached from the ilmenite ore under the optimal conditions. (c) 2006 Elsevier B.V. All rights reserved.