Molybdenum

One Response to “Molybdenum oxide refining?”

1. SciMann Says:
   October 22nd, 2008 at 5:43 am

   _____One is hard pressed to do better than the commercial process without MUCHO investment in research and process development:

   Here’s how now:

   The production of metallic molybdenum from pure MoO3 or ADM is carried out in electrically heated tubes or muffle furnaces, into which hydrogen gas is introduced as a countercurrent against the feed. Usually there are two stages in which the MoO3 or ADM is first reduced to a dioxide and then to a metal powder. The two stages may be carried out in two different furnaces with cooling in between, or a two-zone furnace can be employed. (Sometimes, a three-stage process is utilized beginning at a low temperature of 400° C, or 750° F, to avoid an uncontrolled reaction and prevent sintering.) In the two-stage process, two long-muffle furnaces with molybdenum-wire heating elements can be used. The first reduction is carried out in mild-steel “boats” holding 5 to 7 kilograms (10 to 15 pounds) of oxide, which are fed at intervals of 30 minutes. The temperature of the furnace is 600°–700° C (1,100°–1,300° F). The product from the first furnace is broken up and fed at the same rate in nickel boats to a second furnace operating at 1,000°–1,100° C (1,800°–2,000° F), after which the metal powder is screened. The purest powder, containing 99.95 percent molybdenum, is obtained by reduction of ADM.

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