As an alloy additive for steel, molybdenum is the most important use, and all steels containing molybdenum account for110 of the world crude steel output.
Alloy steel: the consumption of molybdenum is the largest, accounting for 44% of the total consumption of molybdenum in the world, and more than half of molybdenum is added to steel.
Stainless steel: accounting for about 22% of the total molybdenum consumption, usually containing 4%~5% molybdenum, which is often used in places with erosion resistance and corrosion resistance. Such as oil refining, natural gas wells and oil wells, aircraft engines, marine equipment, chemical equipment and other places with serious corrosion.
2, molybdenum and molybdenum-based alloys
Their consumption accounts for about 6% of the total molybdenum consumption in the world. Molybdenum has the advantages of high melting point and boiling point, good high-temperature strength, friction corrosion resistance, high thermal conductivity, small thermal expansion coefficient and good hardenability, and is widely used in aerospace, weapons, electronics, chemical industry and other fields.
When the recovered satellite re-enters the atmosphere, it must overcome the erosion of hot air. Therefore, it is required to withstand vibration, impact, vacuum, radiation and temperature alternation. Molybdenum-based alloy is often used to make the skin of the stable skirt of satellite recovery cabin. TZM molybdenum alloy is also used to manufacture the nozzle of solid fuel rocket engine of space rocket or space shuttle, the nose cone of rocket, the leading edge of aircraft, rudder, heat shield, honeycomb structure and so on.
3. Molybdenum chemical products
This item accounts for about 10% of the total molybdenum consumption, of which about half is used as lubricant, followed by catalyst, pigment, corrosion inhibitor and reagent.
1) Lubricant: High-purity molybdenum disulfide powder is widely used as the king of solid lubrication because of its advantages of wide temperature adaptability, heavy load resistance, direct air resistance and radiation protection.
2) Catalyst: Molybdenum compound is one of the most widely used catalysts. As early as 19 10, British Badishe published the patent of molybdenum compound as catalyst for ammonia synthesis process. Up to now, nCo2O3mMoO is still widely used in ammonia synthesis industry as a catalyst for hydrodesulfurization of diesel oil.
3) Pigments: The most commonly used inorganic yellow pigments in the world today are chrome yellow and cadmium yellow. Lead, chromium and cadmium are highly toxic. In the voice of environmental protection, the development of non-toxic pigments is very important.
4) Micro-fertilizer: Plant organisms are composed of more than 60 elements, and nitrogen, phosphorus and potassium are the three major fertilizers for plants. A few elements, such as boron, manganese, zinc, copper, cobalt, molybdenum and iodine, are called seven micronutrients, and people begin to pay attention to them.
5) Others: Black molybdenum film is used as a dark mirror for solar energy conversion. Effective photothermal solar energy conversion needs to match high solar energy absorption rate and high infrared reflectivity, and black molybdenum film is the best material at present.
Extended data:
Molybdenum is a transition element, which can easily change its oxidation state and play the role of transferring electrons in redox reactions in vivo. In the oxidized form, molybdenum may be in the valence state of +6.
Although it may also be first reduced to the +5 valence state during electron transfer. However, other oxidation states of molybdenum were also found in reductase. Molybdenum is a component of xanthine oxidase/dehydrogenase, aldehyde oxidase and sulfite oxidase, so it is known to be an essential trace element for human body, animals and plants.
The biological characteristics of molybdenum are also very important. It is not only an essential trace element for plants, but also an essential element for animals. Molybdenum is one of the main components of molybdenum flavoprotein protease in plant nitrogen-fixing bacteria. It is also one of the main components of nitrate reductase in plants; It can also stimulate phosphatase activity and promote the synthesis and transportation of sugar and starch in crops; Conducive to the early maturity of crops. Molybdenum is one of seven important micronutrients. ?
Molybdenum is also one of the basic components of xanthine oxidase and aldehyde oxidase in animal liver and intestine, and it is also the basic component of heparin sulfite oxidase. Studies have shown that molybdenum also has obvious caries prevention effect, and has a strong inhibitory effect on the formation of urinary calculi, so people who lack molybdenum are prone to kidney calculi. A healthy person weighing 70 kg contains 9 mg of molybdenum.
For human beings, molybdenum is the only known essential element among the second and third transition elements. Compared with similar transition elements, molybdenum has extremely low toxicity and can even be considered as basically non-toxic.
Of course, excessive intake will also accelerate the oxidation of acetal phospholipids, an elastic substance in the arterial wall of human body. Therefore, in areas with high molybdenum content in soil, the incidence of cancer is low, but the incidence of gout and systemic arteriosclerosis is high. However, animals, especially longhorns, eat too much molybdenum-containing forage and are prone to stomach problems.
References:
Baidu encyclopedia-molybdenum