STUDY OF THE KINETICS OF REDUCTION OF IRON CHROMATE BY HYDROGEN

Background. With a view to exploring alternative process routes for th e reduction of chromite, hydrogen reduction studies of FeCr2O4 were co nducted. Methods. The reduction kinetics of fine synthetic FeCr2O4 pow der was studied isothermally by thermogravimetric measurements in the temperature range from 1173 to 1423 K. Shallow and loosely packed powd er beds and a high flow rate of hydrogen gas were employed. Results. B elow 1373 K, FeCr2O4 was found to be first reduced to iron and chromiu m oxide before the latter being further reduced to chromium. At higher temperatures, the reduction of Cr2O3 appeared to occur before the ful l recovery of iron. Conclusions. The reduction of FeCr2O4 was found to proceed in 2 steps below 1373 K, viz. FeCr2O4(s) + H-2(g) = Fe(s) + C r2O3(s) + H2O(g), Cr2O3(s) + 3H(2)(g) = 2Cr(s) + 3H(2)O(g) The activat ion energy for the reduction of FeCr2O4 to Fe and Cr2O3 was calculated to be 131 kJ . mole(-1).