Effects of mechanical activation and oxidation-reduction on hydrochloric acid leaching of Panxi ilmenite concentration

The effects of oxidation-reduction treatment and mechanical activation on the hydrochloric acid leaching performance of Panxi ilmenite concentration were investigated. The results show that both of oxidation-reduction treatment and mechanical activation significantly accelerate the extraction of Fe, Ca and Mg from Panxi ilmenite concentration; however, the CaO and MgO contents of the calcined residues obtained from oxidized-reduced ilmenite concentration are higher than the standard values required by chlorination process. The Ca and Mg in oxidized-reduced ilmenite concentration can be leached much faster after mechanical activation, yielding a synthetic rutile which meets the requirements of chlorination process containing 90.50% TiO2 and 1.37% total iron as well as combined CaO and MgO of 1.00%. The optimum oxidation and reduction conditions are as follows: oxidization at 900 °C in the presence of oxygen for 15 min and reduction at 750 °C by hydrogen for 30 min.