Study of the Reduction of Industrial Grade MoO3 Powders with CO or CO-CO2 Gases to Prepare MoO2

Industrial grade MoO2 powders have a plenty of advantages relative to MoO3 in the direct alloying steelmaking processes. In this work, the reduction of industrial grade MoO3 powder with CO gas or the mixed gases of CO and CO2 has been investigated in detail in order to prepare industrial grade MoO2 powder. It is found that reaction temperature has a significant effect on the product composition. Using pure CO as the reducing gas, for temperatures below 868 K (595 °C), the main product is MoO2 with some whisker carbon; for temperatures above 868 K (595 °C) the main reaction products are MoC and amorphous carbon; as the reaction temperature further increased, the final reaction product is Mo2C. In addition, Mo4O11 is always formed as an intermediate product during the reaction processes both at lower and higher temperatures, which is similar to that observed on reduction of MoO3 by H2. It is found that adding CO2 to the reducing gases eliminated carbon formation but still allows the formation of MoO2 during the reaction process. This method may be applied to produce industrial grade MoO2.