Gaseous reduction of molybdenum oxide - in two stages with individual control of temp. and gas compsn.

摘要

Molybedenum trioxide is continuously reduced to metal by feeding it in pelletised form into a first reaction zone where it is heated to 580-650 degrees C in contact with an inert carrier gas containing 3 to 10 mol.% of hydrogen. The flow rate of gas and pellets is such as to provide a stoichiometric excess of hydrogen ranging from 1:1 to 10:1 mols of hydrogen per mol. of trioxide and to effect complete reduction to the dioxide while the heat of the reaction maintains the temperature in the above range. The pellets are continuously transferred to a second zone maintained above 900 degrees C where they are contacted by an inert carrier gas containing 20 to 80 mol.% hydrogen such that reduction to metal is completed endothermically. Finally, the pellets are transferred to a third zone for cooling under protective atmosphere. Pref. the feed pellets pass vertically down the reaction zones in countercurrent to the gas flow. A process for continuous processing of molybdenum dioxide according to the first stage as above is also claimed. The process provides the advantage of continuous operation and permits effective control of the reduction reactions. The prod. is used particularly as a steel making additive.