In order to make fine Mo powder for metallising of ceramic electron tube, we prepared highly voluminous MoO 3 powder by means of oxidation followed by sublimation of Mo filament scrap and then reduced the sublimated MoO 3 to metallic Mo by hydrogen gas.
We found vertical type furnace was suitable for this purpous and the key point of operation was found to prevent the formation of the Mo lower oxide. A good result has been obtained by choosing the furnace temperature of 900-1200°C and treating capacities of 5kgMo/ hr at 1m3/min air draught ; 7kgMo/hr at 1.4m3/min were attained, and MoO 3 recovery was kept over 96%.
Sublimated MoO 3 had a purity of 99.9% up and mean particle size of 0.50μ. And the hydrogen-reduced Mo powder indicated its particle size at 0.55μ and proved good result for ceramic use.
