Patent holder (s):
PJSC “State Research and Design Institute of Rare-Metal Industry “Giredmet”
M.V. Vorobyova, E.E. Edrennikova, V.V. Ivanov, E.A. Levashov, N.N. Rakova
The invention relates to rare refractory metal metallurgy, particularly to processes for producing molybdenum nanodispersed powder from its compounds by reduction using gaseous reducing agents. Ammonium paramolybdate is reduced in two stages. At the first stage, base ammonium paramolybdate is reduced by ammonia gas while continuous heating at temperature-rise rate of 180-200°С per hour up to reaching temperature of 540-560°С producing intermediate compound consisted of molybdenum oxide-nitride phase. Then temperature is slowly raised up to 850°С, and at the second stage, intermediate compound is reduced to metal by gaseous hydrogen using ageing at the specified temperature during 2,0-2,5 hours. Along with that, first and second stages of reduction are performed in the same reacting volume by changing composition of gas phase supplied in reaction zone. Production of powder having interstitial impurity content no more than 50 ppt (99,995 mass.%) and achievement of yield ratio no less than 80-85% are provided.