Molybdenum is produced by reducing pure molybdenum trioxide or ammonium molybdate in hydrogen gas.The chemical reduction of pure molybdenum trioxide or ammonium diamolybdate to metal requires two stages because the direct conversion to metal releases heat, which inhibits the process. The first stage of reduction to MoO2 is carried out in the range of 450-650℃. In the second stage of reduction reaction, molybdenum dioxide is reduced to molybdenum metal in the temperature range of 1000-1100℃. Historically, both stages were accomplished by pushing a small boat containing the powder of the reaction material into an atmosphere of flowing hydrogen gas in a tubular furnace. Rotary furnaces are becoming increasingly common in first-stage reduction operations, in which powder is continuously fed through rotating inclined tubes in a flowing hydrogen atmosphere, thereby increasing production efficiency.
The melting point of molybdenum is 2620℃. Because of the strong interatomic bonding force, the strength is very high at room temperature and high temperature.
It has small expansion coefficient, large electrical conductivity and good thermal conductivity.
It does not react with hydrochloric acid, hydrofluoric acid and alkali solutions at room temperature, and is only dissolved in nitric acid, aqua regia or concentrated sulfuric acid. It is also quite stable to most liquid metal, non-metallic slag and molten glass.