The application of molybdenum
1. Steel industry
According to the statistics of molybdenum consumption around the world, the application of molybdenum in iron and steel industry still occupies the most important position. As an alloying element of steel, molybdenum can improve the strength of steel, especially the high temperature strength and toughness. Improve the corrosion resistance of steel in acid and alkali solution and liquid metal; Improve wear resistance and hardenability, weldability and heat resistance of steel. Molybdenum is a good carbide-forming element that is not oxidized during steelmaking and can be used alone or in combination with other alloying elements.
Molybdenum is used with chromium, nickel, manganese and silicon to make different types of stainless steel, tool steel, high speed steel and alloy steel. Made of stainless steel has good corrosion resistance, can be used for oil mining corrosion resistant steel pipe, car shell, sewage treatment equipment. A stainless steel with about 6 percent molybdenum can also replace titanium in desalination plants, ocean-going ships, and offshore oil and gas pipelines.
Molybdenum series high speed steel has the advantages of carbide inhomogeneity, wear resistance, good toughness, high temperature plasticity and so on. Molybdenum alloy steel can be used to manufacture machine tool structural components, industrial vehicles and earth-moving equipment.
2, agricultural fertilizer
Molybdenum is one of the essential "trace elements" in plants, which can significantly improve the quality and yield of legumes, grasses and other crops. Therefore, ammonium molybdate is often found in fertilizers. Molybdenum can promote the fixation of nitrogen in the air by rhizobia and other nitrogen-fixing organisms, and further convert nitrogen into proteins needed by plants. Molybdenum can promote the uptake of phosphorus by plants and play its role in plants. Molybdenum can accelerate the formation and transformation of sugars, improve the content and stability of chlorophyll and vitamin C in plants. In addition, molybdenum can improve plant drought and cold resistance and disease resistance.
The application of molybdenum fertilizer is characterized by small amount, large effect and low cost. It is an important measure to improve agricultural yield, especially soybean harvest.
3. Electronics and electricity
Molybdenum has good conductivity and high temperature performance, especially the thermal expansion coefficient of glass is very similar, so it is widely used in the core wire, lead wire, side rod and other parts of the spiral filament in the bulb, in the electron tube as grid and anode support material.
In very large scale integrated circuits, molybdenum is used as metal oxide semiconductor gate. The bimetal effect can be eliminated by installing integrated circuits on molybdenum. The ultra-thin seamless molybdenum tube (about 15μm) can be used as the anode bracket for the picture tube of high definition TV sets. Molybdenum discs can also be used as heat shields for power transistors and substrates and heat sinks for silicon rectifiers. In addition to pure molybdenum, Mo-Re alloy can be used as the structural material of electron tube and special bulb in modern electronic industry, mo-50Re and TZM alloy can also be used as thermionic cathode structural component in high power microwave tube and millimeter wave tube.
4, car spraying
The melting point of molybdenum is as high as 2620℃, and it has good high temperature performance and corrosion resistance, and has strong bonding force with steel, so it is the main thermal spraying material in the production of automobile parts. Thermal spray materials can significantly improve the performance of piston rings, synchronous rings, forks and other worn parts, and are also used to repair worn crankshafts, rollers, shafts and other mechanical parts.
5, high temperature components
Molybdenum is often used as heating element and structural material for high temperature furnace because of its high purity, high temperature resistance and low steam pressure. Molybdenum has good ablative resistance in melted quartz, and is often used in the glass industry as an electrically fused electrode with a service life of more than a year. In addition to being used as electrode, molybdenum can also be used as high temperature structural material for glass melting, such as guide channels, pipes, etc. The application of molybdenum instead of platinum in glass fiber wire drawing furnace is effective and the production cost is greatly reduced. In addition, molybdenum and its alloy can also be used as hot isostatic pressing furnace rack, heat insulation screen, sintering and steam coating boat, etc.
Molybdenum silicide is a kind of widely used electrothermal component material, with high temperature oxidation resistance, excellent corrosion resistance, high melting point and other characteristics, long life.
6. Oil extraction
Molybdenum can not only be used in oil and gas field drilling pipelines, but also often combined with cobalt and nickel as a catalyst for refining and pretreatment of petroleum, mainly petroleum, petrochemical products and liquefied coal desulfurization. In the hydrogen process. The sulfide reacts with hydrogen on the surface of the catalyst, allowing the sulfur ions to come out as hydrogen sulfide. It also removes nitrogen and metal impurities from the crude oil to reduce the toxicity of these impurities to other catalysts during refining, improving the color, smell and stability of the product. The passivated molybdenum catalyst leaves a layer of carbon on its surface. If the carbon layer is burned off, the catalyst can regain its activity, and the life of the catalyst can be 1-5 years. Molybdenum plays an important role in petroleum cracking and reforming and is an ideal electron donor and carrier.
Molybdenum and its alloys can also be used in nuclear industry, aerospace and environmental protection.
