Introduction to the uses and applications of molybdenum

Overview of molybdenum applications
Molybdenum is used in the iron and steel industry in the first place, accounting for around 80% of total molybdenum consumption, followed by the chemical industry with around 10%. In addition, molybdenum is used in the fields of electrical and electronic technology, medicine and agriculture, which account for around 10 percent of total consumption.

Alloys

Molybdenum is consumed most intensively in the iron and steel sector, where it is mainly used in the production of alloy steels (approx. 43% of total molybdenum consumption in iron and steel), stainless steels (approx. 23%), tool and high-speed steels (approx. 8%), and cast iron and rolls (approx. 6%). Most of the molybdenum is used directly in steelmaking or cast iron after being briquetted as industrial molybdenum oxide, while a small proportion is first smelted into ferromolybdenum and then used in steelmaking. Molybdenum as an alloying element in steel has the following advantages: it increases the strength and toughness of the steel; it improves the corrosion resistance of the steel in acid and alkaline solutions and liquid metals; it increases the wear resistance of the steel; and it improves the hardenability, weldability, and heat resistance of the steel. For example, stainless steels containing 4%-5% molybdenum are often used in places where erosion and corrosion are more severe, such as marine equipment and chemical equipment.

To molybdenum as a substrate by adding other elements (such as titanium, zirconium, hafnium, tungsten and rare earth elements, etc.) constitute non-ferrous alloys, these alloying elements not only molybdenum alloys play the role of solid solution strengthening and maintaining low-temperature plasticity, but also the formation of stable, diffuse distribution of carbide phases, to improve the strength of the alloy and recrystallization temperature. Molybdenum-based alloys are used for high heating elements, extruded abrasives, glass melting furnace electrodes, spray coatings, metal working tools, and spacecraft components because of their good strength, mechanical stability, and high ductility.

Chemical field

Lubricant: Molybdenum dioxide is a good solid lubricant because of its low coefficient of friction, high yield strength, and its ability to be used normally in a vacuum and at various ultra-low and high temperatures, and thus is widely used in gas turbines, gears, molds, aerospace, nuclear industry and other fields.

Catalyst: Molybdenum compounds are one of the most versatile catalysts and are widely used in the chemical, petroleum, plastics, textile and other industries. For example: molybdenum disulfide has anti-sulfur properties, and can catalyze the hydrogenation of carbon monoxide to produce alcohols under certain conditions, which is a promising C1 chemical catalyst; molybdenum is used in combination with cobalt and nickel as a catalyst for petroleum refining pretreatment. Other common catalysts containing molybdenum are: molybdenum disulfide, molybdenum oxide, molybdate, ammonium sec-molybdate and so on.
Pigment: Chrome yellow and cadmium yellow are the most commonly used inorganic yellow pigments in the world today, but lead, chromium and cadmium are toxic, while molybdenum yellow is not only non-toxic, but also has a bright color, light and heat stability is also good, and thus is used in pigments and inks, plastics, rubber products and ceramics.
Organic polymer flame retardant and smoke reducer: in halogenated polyester by adding 3% -4% of molybdenum trioxide, the critical oxygen index can be increased by 3% -4%, the amount of carbon generated during combustion increased by 4% or so, so that the amount of smoke reduced by 3%.
Corrosion Inhibitors: Molybdate has very low toxicity and is weakly corrosive to organic additives added to corrosion inhibitors and is commonly used in the construction of air conditioning cooling water and heating systems to prevent mild steel from being corroded.

Electrical and Electronic Fields

Molybdenum has good electrical conductivity and high temperature resistance, with a coefficient of thermal expansion similar to that of glass, and is widely used in the manufacture of spiral filaments such as core wires, lead wires and hooks. In addition, molybdenum wire is also an ideal electrode wire for EDM wire-cutting machines, capable of cutting all kinds of steel and hard alloys, and its discharge processing is stable, which effectively improves the precision of molds.
The single-layer molybdenum pyroxene material has good semiconductor properties, some performance over the now widely used silicon and graphene, is likely to become the next generation of semiconductor materials. California Institute of Nanotechnology has successfully used MoS2 to create a molybdenum pyroxene-based flexible microprocessor chip, this microchip is only 20% of the size of the equivalent silicon-based chip, power consumption is extremely low, and molybdenum pyroxene made of transistors in standby mode for the power consumption of silicon transistors one hundred thousandth of the power consumption, and cheaper than the same size of graphene circuits, and its circuits are also very flexible, extremely thin, can be attached to the human body skin.

Medical field

Molybdenum is one of the essential trace elements and a component of many enzymes. Its main function in the body is to participate in the mutual reactions between sulfur, iron and copper. The right amount of molybdenum can promote the development of the human body, enhance the storage of oxygen in the body, inhibit tumors, maintain the energy metabolism of the heart muscle, protect the heart muscle, and the lack of molybdenum can lead to dental caries, kidney stones, Crohn's disease, macroglossia, esophageal cancer, etc. Therefore, molybdenum is also used in medicine, such as ammonium molybdate, a drug is mainly used for long-term dependence on the intravenous high nutrition of the patient.

Animal husbandry

The biological role of molybdenum is mainly based on its role as a component of certain molybdenum-containing enzymes in the animal's body, indirectly influencing the biological activity of the enzymes. In addition, molybdenum plays a special role in the nutritional metabolism of ruminants. On the one hand, molybdenum, as a component of nitrate oxidase of rumen microorganisms in ruminants, is directly involved in the conversion of feed nitrate in the rumen, and on the other hand, molybdenum, as a cofactor of sulphate oxidase, has a stimulating effect on rumen microorganisms, which contributes to the digestion of crude fiber-type material in ruminants and thus promotes their Growth. Therefore, when the molybdenum content in pasture and feed is insufficient, it is necessary to add molybdenum additives to the feed in accordance with strict nutritional needs and process technology requirements to meet the needs of the animal, the most common example being the addition of 10 mg/d of molybdenum to the feed of dairy cows.

Agriculture

Molybdenum is one of the essential "trace elements" in plants, and a lack of molybdenum will affect normal plant growth. As an essential trace element for plant growth, molybdenum not only promotes phosphorus uptake, but also accelerates the formation and conversion of alcohols in plants, increases the content of chlorophyll and vitamin C, and improves the plants' resistance to drought, cold and disease. In view of the importance of molybdenum to plants, many countries have begun to produce and use of molybdenum-containing trace fertilizers, such as China's Changsha County, Hunan Province, Nanhua Township, with ammonium molybdate seed mixing, peanut yield increase of 32.2%, Heilongjiang State Farm on soybean molybdenum fertilizer, soybean yields increased by about 10%.