Use and Preparation of Molybdenum Trioxide


Molybdenum application continues to expand alloys and used in the field of chemical industry, which makes molybdenum products get more and more attentions. As the major molybdenum element compounds, the production and application of MoO3 nanopowder are also highly concerned. Here we provide you a brief introduction of the use and preparation of molybdenum trioxide.

Molybdenum trioxide is a colorless or pale yellow, transparent rhombic crystal, melting point of 795°C, boiling point 1155°C ( sublimation ), insoluble in water but soluble in ammonia and alkali, being able to react with the alkali solution and the many metal oxides to generate molybdate salts and multi-molybdate salts. Generally, the molybdenum trioxide is gas, composed of molecules, with a double bond between Mo-O. When solid, anhydrous molybdenum trioxide is of orthorhombic system, comprising a layered structure composed of octahedral MoO6 deformation. The octahedral is chain-like, cross linked by oxygen atoms, among which a Mo-O (non-crosslinked oxygen) bond length is shorter than other keys.

Molybdenum trioxide is mainly made by the burning of molybdenite or fusion sintering molybdic after precipitating the molybdic acid by adding hydrochloric acid to ammonium molybdate. The preparation process is: crush molybdenite concentrate to 60-80 mesh according to ammonium thermal decomposition method, then put it into a 500-550°C roaster for oxidizing roasting , after leaching with ammonia, the ammonium molybdate solution is obtained after impurities get removed, heating to 40-45°C, then add nitric acid under stirring to neutralize until the pH = 1.5 when eight molybdate precipitate is generated, after filtering, centrifugal dewatering, dissolved in aqueous ammonia under 70-80°C, and then concentrated by evaporating to get the secondary molybdate ammonium, and through thermal decomposition at 550-600°C, then we can get the molybdenum trioxide finished product.

Molybdenum trioxide is mainly used for molybdenum and molybdenum compounds. It is also as catalysts in the petroleum industry, but also for enamel glaze pigments and drugs, very widely used. Nevertheless, there is a point that you need to be reminded by metal powder supplier that molybdenum trioxide irritates to eyes, skin, mucous membranes and upper respiratory tract. You have to take necessary protective measures for the transport and storage.

Overall, different preparation methods for diverse uses of molybdenum trioxide products can be adopted. As long as the raw material, calcination temperature and particle size are in good control, it is impossible to produce high quality molybdenum trioxide products.