Leaching kinetics of Panzhihua ilmenite in sulfuric acid

About 90% of the titanium deposits in China are located in the Panzhihua area. The dissolution of Panzhihua ilmenite in sulfuric acid was investigated. The kinetic experiments were carried out with an initial acid/ilmenite (wt.) ratio of 500:15, a sulfuric acid concentration of 15.4 M and temperatures from 100 to 198degreesC. The results show that the leaching kinetics can be described by shrinking core model. Both surface reaction and diffusion through the product layer are effective on the leaching rate. The kinetics can be expressed by the following equation: t = [0.00766/ (2.74 x 10(7) e(-72575/RT))] [1 - (1 - x)(1/3)]{1 + (11 - 0.016T)[1 + (1 - x)(1/3) - 2(1 - x)(2/3)]} The apparent activation energy was estimated to be 72.6 kJ/mol. This kinetic relationship was used to simulate non-isothermal and the pseudo-adiabatic experiments under industrial conditions. The simulated values were consistent with the experimental data. (C) 2004 Elsevier B.V. All rights reserved.