Kinetics of oxychlorination of chromite Part II. Effect of reactive gases

The effects of Cl-2/O-2 ratio, P(Cl-2+O-2), P-Cl2, and P-O2 on the oxychlor ination rate of the chromite mineral were determined between 750 and 1000 d egreesC using isothermal TGA measurements. The effect of the gases' composi tion on the oxychlorination rate of chromite were compared with those resul ting from the oxychlorination of simple oxides of the chromite (Cr2O3, Fe2O 3 and MgO). The apparent reaction orders with respect to Cl-2 + O-2, Cl-2, and O-2 for the chromite oxychlorination at 750 degreesC were about 0.94, 1 .24, and -0.30, respectively. At 1000 degreesC, apparent reaction orders wi th respect to the reactive gases changed significantly as the reaction prog ressed. Boat experiments were carried out to oxychlorinate a chromite concentrate b etween 600 and 1000 degreesC. The reaction products were analyzed by SEM, X RD and chemical analysis. The oxychlorination of a chromite concentrate at about 800 degreesC led to the partial elimination of iron increasing the Cr /Fe ratio in the treated concentrate. A part of chromium was also oxychlori nated and it was recovered as chromium oxychloride (CrO2Cl2). (C) 2001 Else vier Science B.V. All rights reserved.