Jiang L.,Molybdenum Research Center |
Jiang L.,Xian University of Architecture and Technology |
Xi Z.,Molybdenum Research Center |
Li L.,Molybdenum Research Center |
And 4 more authors.
Xiyou Jinshu/Chinese Journal of Rare Metals | Year: 2011
Industrial process on molybdenum trioxide preparation from off-grade molybdenite (grade less than 45%) in aqueous solution by autoclave oxidation was studied. The off-grade molybdenite was processed with hydrochloric acid leaching technique at atmospheric pressure to remove most of the lead, copper, iron and other impurities to enhance the molybdenum concentrate grade. The refined molybdenite was oxidized by O 2 under pressure to prepare molybdenum trioxide. A single-factor experiment was carried on, in that, the effects of temperature, partial pressure of oxygen, particle size of molybdenite, stirring speed and reaction time were studied. Under technology stability experiment, optimal process parameters were obtained: temperature of 200°C, oxygen partial pressure of 700 kPa, molybdenite particle size of <75 μm, stirring speed of 400 r·min -1, assistant oxidant amount of 2% and reaction time of 2~3 h. With the optimal process, the oxidation rate of molybdenite was more than 99%. The process used hydrochloric acid leaching at atmospheric pressure together with autoclave oxidation approach to dispose the off-grade molybdenite, the molybdenum concentrate grade could be upgraded greater than 10%, the oxidation rate of molybdenum was high. In that, Mo of 10% dissolved into the solution, and Mo of 90% was transformed into molybdenum oxide of qualified industrial products. The prepared molybdenum oxide contained extremely low metal impurities and was suitable for producing ammonium molybdate.