Study on reduction of MoO2 by carbon diffusion to prepare molybdenum powder

In this study, MoO2 was reduced by an unmixed carbon reduction method. Effects of reduction temperature, reduction time and distance between carbon and MoO2 on the phase composition of reduction products were investigated. Results show that the phase change during the reduction process are MoO2→Mo2C→Mo with the increase of temperature. The reduced product is Mo2C when reduction temperature is 1000 °C and 1050 °C. Pure Mo can be obtained when the reduction temperature increases to 1100 °C. The reduced product changed from nearly spherical Mo particles with fine molybdenum dioxide particles attached on surface to polyhedron Mo particles with smooth surface when the distance between carbon and MoO2 decreases from 10 mm to 1 mm. The reaction showed a similar change with the changes of the reaction time. The difference is that there will be residual Mo2C in reduced product when reduction time was 1 h. This method of carbon reduction can provide low carbon concentration by controlling the carbon distance to avoid the existence of molybdenum carbide in the product of molybdenum preparation.