Extractive metallurgy of molybdenum

Molybdenum metallurgy involves a series of processes that combine mineral processing, pyrometallurgy, and hydrometallurgy, as dictated by the nature of the resource. Indeed, like most non-ferrous base metals, molybdenum is associated with sulfur, and molybdenite (MoS ₂ ), its primary mineral, is generally found in low to very low concentrations within complex ores characterized by their mineral associations, particularly in copper sulfides. Consequently, most molybdenum deposits are copper deposits from which molybdenite is recovered as a byproduct, provided that the technical and economic conditions are favorable.

The standard process for recovering molybdenum from ores involves first producing a molybdenite concentrate through flotation. This concentrate is then processed using various pyrometallurgical and/or hydrometallurgical methods to produce products suitable for industrial use. Typically, MoS ₂ is converted into technical-grade MoO ₃ oxide through oxidative roasting. The technical oxide can be purified by simple washing with water, by sublimation, or by leaching in an ammonia solution. All these operations are energy-intensive, and in addition to energy costs, there are constraints due to the nature of low-grade ores. Consequently, molybdenum mines have historically alternated between closure and reopening, even though this metal is of strategic importance in the manufacture of high-tech alloys.

Molybdenum oxide is the raw material used to produce molybdenum metal and other organic and inorganic compounds. In certain applications, molybdenum disulfide (MoS ₂ ) is also used. High-purity molybdenum metal is available in powder form, as a solid block, or in ingots.

Secondary molybdenum is recycled through hydrometallurgical and/or pyrometallurgical processes, depending on the types of materials to be recovered.

Molybdenum and its compounds are used in a wide range of industrial sectors, including the production of stainless steel, special steels, superalloys, cast iron, catalysts, lubricants, pigments, and more.