Many-faced molybdenum: where applicable, properties, biological role in the human body

Chemistry is the foundation of our life. All household items consist of compounds of the elements of the periodic table. Every minute there are complex transformations in the human body, in which chemical substances participate. This article will tell you about such a metal as molybdenum: where it is applied, its properties and role in the human body.

Take a closer look at the history

Minerals that have molybdenum in their composition were known even in Ancient Greece. These natural compounds had a graphite-like structure. Therefore, often used along with it to create slates. Molybdenite MoS₂ had a greyish-green hue when writing on paper. For the characteristic brilliance he was given the name molybdaena - "like lead."

Karl Wilhelm Scheele carried out research that helped synthesize MoO тре trioxide, but because of the lack of a suitable furnace, he was unable to separate the metal in its pure form. Jönns Jakob Berzelius succeeded in obtaining molybdenum in 1817 by reducing the oxide not with coal, but with hydrogen. The synthesized chemical element was thoroughly investigated and described in the works of the scientist.

Physical properties

What is molybdenum? It is a light gray metal, which in its pure form is resistant to oxidation (under normal conditions). With increasing temperature to 400-600 degrees, this ability decreases, and MoO тре trioxide is formed.

Molybdenum is plastic and forging, it is easily subjected to stamping. The density of the metal is 10.2 g / cm ³ , the melting point is 2620 ° C, and the boiling point is 4800 ° C. From these indicators it is clear that it is rather refractory. The presence of carbon, nitrogen or sulfur impurities affects the physical properties, in particular, the substance becomes brittle and brittle. Molybdenum is a paramagnet. As the temperature increases, its strength increases significantly.

Natural compounds of molybdenum, production

One should know that molybdenum does not occur in pure form, it is present in nature exclusively in compounds with other elements. The approximate content of metal in the earth's crust is 3 ∙ 10 ^-4 %. There are about 15 minerals, of which the most common are:

• Disulfide MoS ₂ - molybdenite;
• CaMoO ₄ - povellite;
• PbMoO ₄ - wulfenite.

The main deposits of these compounds are closely related to deposition processes in hydrothermal sources.

For industrial purposes, the disulfide of the molybdenum element is extracted. Its use to produce pure metal is very important. This happens with the help of ore dressing by flotation. This is how the concentrate is obtained, which is subsequently fired.

2MoS ₂ + 7O ₂ = 2MoO ₃ + 4SO ₂

The separated oxide is purified and reduced by a dry hydrogen current at a temperature of 700 degrees. The product of the reaction is molybdenum powder. In the future, it can be used in pure form or as a material for the creation of rolling and extruded products.

Manufacture of alloyed steels

Black metallurgy uses a powder of molybdenum substance. Where does it apply? For alloying steels and cast irons. Adding this element to the composition of alloys significantly improves their quality. Increases elasticity, resistance to wear, resistance to shocks. In structural steels add about 0.5% molybdenum, from this their structure becomes fine-grained and more homogeneous, reducing the fragility of the final products.

The addition of other substances makes it possible to obtain special compositions widely used in various industries. Alloys, which include cobalt and nickel (50-60%), and chromium (about 20-28%) are alloyed by adding molybdenum. Where is this material used? The answer lies in its special properties - high heat resistance. It is used in the manufacture of parts for plating aircraft and rockets.

Application of alloys with molybdenum

When adding niobium, titanium and other superalloys to molybdenum, the heat resistance of alloys increases. Such a composition can be used to create details of gas turbines and combustion chambers in rocket engineering.

In alloys with a high content of molybdenum (17-28%), corrosion resistance increases. They are not afraid even of interaction with any acid (except for the hydrofluoric acid).

The refractory properties of molybdenum and its use in creating special pipes are of great importance in nuclear power engineering. Such products are able to withstand the impact of molten lithium. It acts as a coolant in uranium reactors. In addition, molybdenum itself in the form of an isotope Mo-99 was used as an indicator in the nuclear industry.

Due to the refractory properties of molybdenum, molds for casting parts made of copper, aluminum and zinc are formed from it. The high strength of the metal makes it possible to carry out processes under high pressure.

Rolling and stamping, application

From the blanks, obtained during the melting of powder, produce rolling products - bars and wire. They consist of a pure metal called molybdenum. Where is this product used? Most often it is used in the manufacture of thermocouples, which serve to measure temperatures above 2000 ⁰C. Hooks and cores for winding tungsten filament in an incandescent lamp are also made of molybdenum wire. Inputs of cathodes and focusing electrodes in X-ray tubes and generator lamps must be reliable and meet the requirements of high refractoriness of the metal. For these purposes, the rolling of molybdenum is excellent.

Rods and plates are used instead of electrodes in high-temperature melting furnaces. They should be in a special medium consisting of argon, hydrogen or vacuum. Due to the fact that molybdenum does not enter into chemical reactions with glass, it is used for making parts of a melting furnace.

Application in other industries

Molybdenum has found application in the oil industry. There it is used as a catalyst capable of purifying products from sulfur impurities. On the basis of aluminum disulfide, lubricants are made. They stabilize the operation of various devices and protect the surfaces from mechanical effects at high temperatures. It has such lubrication and anti-corrosion properties.

In the manufacture of paintwork materials, where molybdenum and its oxides are used, persistent pigments of yellow-orange tones are obtained. Synthesis of artificial fibers also does not pass without this substance. To increase the nitrogen content in the soil, microfertilizers containing molybdenum are used.

The role of molybdenum in the body

Molybdenum plays a significant role in the human body. It participates in the synthesis of hemoglobin, nitrogenous and purine metabolism. Responsible for the assimilation of iron and vitamin C, is a powerful antioxidant. The microelement has an oncoprotective, rejuvenating effect.

Products rich in molybdenum are legumes and cereals, leafy vegetables. The necessary amount of a microelement enters the body every day, if you eat right. Its shortage can be replenished using mineral complexes.