The effect of karrooite contents on the isothermal reduction kinetics of pseudobrookite-karrooite (Fe2TiO5-MgTi2O5) powder was investigated under a 30% CO/70% Ar atmosphere at 1123, 1173, and 1223 K. The reduction rate decreased with increasing karrooite contents and increased with increasing reduction temperatures. The reaction mechanism with different stages were studied. The average apparent activation energies were 38.34, 39.60, 41.92, and 89.56 kJ/mot for contents of 0%, 9.93%, 19.86%, and 39.72% karrooite, respectively. The mechanism of karrooite in blocking the reduction of pseudobrookite was clarified. The morphology of the reduced sample with different amounts of karrooite were also examined. (C) 2018 Elsevier B.V. All rights reserved.