Development of an Improved Sub-Molten Salt Method for Production of Potassium Titanate from Ilmenite under Industrial Conditions

It was reported that the industrial application of Sub-Molten Salt method for production of potassium titanate from ilmenite concentrate is limited by feed particle size. Therefore, the objective of this study was to develop an improved approach for decomposition of ilmenite under industrial conditions. Using an ilmenite concentrate from Kahnooj Titanium Complex, experiments were performed at different conditions designed by the Response Surface Methodology (RSM) method. From the results of the tests, it can be noted that high conversion rate would be achieved even for particle size distribution similar to the industrial conditions. Statistical analysis of the results showed that conversion rate of titanium was significantly affected by process temperature. Optimized decomposition conditions were obtained at temperatures around 220oC, KOH concentration of 84 wt%, KOH-to-ilmenite mass ratio of 9 and stirring rate of 800 rpm. Under these conditions, more than 96% of titanium can be recovered as potassium titanate. A quadratic model was obtained for the prediction of decomposition. Validity of the model was also experimentally confirmed. Observed effects of the relevant operating variables on conversion rate were consistent with a chemical reaction controlled kinetic model. Apparent activation energy for decomposition of ilmenite was found to be 80.15 kJmol−1.