Kinetics of the Oxidative Roasting of Low Grade Mongolian Molybdenite Concentrate

Molybdenite concentrate is the major mineral for the molybdenum industry. The industrial processing of molybdenite concentrate is first to convert to technical grade molybdenum trioxide by its oxidative roasting, followed by its purification by distillation or its ammonia leaching. In the present research, detailed experimental results for the oxidative roasting of low grade Mongolian molybdenite concentrate are presented. The experiments were carried out in the temperature range of 778 to 838 K under air atmosphere by using a thermogravimetric analysis technique. The particle size of the molybdenite concentrate was varied between 53 and 103 pin. As an example of the oxidative roasting of low grade Mongolian molybdenite concentrate, more than 95% of 53 mu m particle size molybdenite was converted to molybdenum trioxide in 40 min at 823 K. The Jander equation was found to be useful in describing the rates of the oxidative roasting, which had an activation energy of 215.0 to 259.3 kJ/mol (51.4 to 62.0 kcal/mol) for various sizes, such as 53 pin, 67 mu m and 103 pm. [doi: 10.2320/matertrans.M2009197]