THERMODYNAMICS AND KINETICS OF PRODUCING SYNTHETIC RUTILE BY SELECTIVE CHLORINATION OF ILMENITE

The phase equilibrium diagram of Fe-Ti-C-O₂-Cl₂ system is studied for the preparation of synthetic rutile by selective chlorination of ilmenite. The changes of free energy are calculated in the reactions between O₂ and certain chlorides. By means of a process-"oxygen-induction one-step selective chlorinatio", the key technical problem is solved which requires a continuous process for "self-heating" chlorination. The technical parameters have been verified by lab-test, pilot test and industrial-scale test. The study has proved that the dynamic model of the selective chlorination process is a "shrinking core reaction model in which the solids' particle size is kept unchanged", with the activation energy in the dynamic zone being 34.33 kJ/mol and that in the diffusion zone 0.8 kJ/mol. The fluidized bed chlorinator without perforated-plate developed in this process can stably and continuously operate in a long period of time. The process and the relevant equipment have been successfully applied in the industrial production, with the grade of resultant synthetic rutile being 92.1%, and even up to 95% through the additional table concentration and magnetic separation. The reactor's capacity can reach 12.4 t/m²·d.