Mechanism of Aluminothermic Reduction of Chromium Oxide

Aluminothermic reduction of chromium oxide is an exothermic autocatalytic reaction and then a potential method of recycle of chromium from oxide. The purpose of the present research is to investigate the kinetic process and to ind its critical temperature of this reaction.Sample pellets are prepared by mixing of aluminum powder and chromium oxide powder according to stoichiometry of reaction. Experiments are conducted at 1423 K, 1473 K and 1523 K, respectively, under argon atmosphere. The reacted pellets are then investigated by SEM coupled with EDS and XRD.It is found that the reaction drastically proceeds and is completed in only 2 minutes above a critical temperature of 1523 K. The chromium oxide is reduced by aluminum to form molten chromium and a slag of aluminum oxide is formed on its surface.