Argon is a special element of the periodic system

We all know that argon is used for welding different metals, but not everyone thought about what this chemical element is. And yet his story is rich in events. What is characteristic, argon is an exceptional copy of Mendeleyev's periodic table, which has no analogues. The scientist himself was surprised at the time, how he could get here at all.

About 0.9% of this gas is present in the atmosphere. Like nitrogen, it has a neutral character without color and odor. To maintain life, it does not fit, but it is simply indispensable in some areas of human activity.

A short digression into the history

For the first time it was discovered by an Englishman and physicist by education G. Cavendish, who noticed the presence in the air of something new, resistant to chemical attack. Unfortunately, Cavendish did not know the nature of the new gas. A little over a hundred years later, another scientist, John William Strath, noticed this. He came to the conclusion that in the nitrogen from the air there is some admixture of gas of unknown origin, but argon or something else, he could not yet understand.

At the same time, the gas did not react with various metals, chlorine, acids, alkalis. That is, from a chemical point of view, was inert. Another surprise was the discovery - the molecule of the new gas includes only one atom. And at that time such a composition of gases was still unknown.

The public announcement about the new gas has shocked many scientists from all over the world - how could it have been possible to overlook the new gas in the air for many scientific studies and experiments ?! But not all scientists, including Mendeleyev, believed in the discovery. Judging by the atomic mass of the new gas (39.9), it should be located between potassium (39.1) and calcium (40.1), but the position was already occupied.

As already mentioned, argon is a gas with a rich and detective history. For a while it was forgotten, but after the discovery of helium, the new gas was officially recognized. It was decided to take for him a separate zero position, located in between halogens and alkali metals.

Properties

Among other inert gases that enter the heavy group, argon is considered the easiest. Its mass exceeds the air weight by 1.38 times. In the liquid state, the gas passes at a temperature of -185.9 ° C, and at -189.4 ° C and normal pressure hardens.

From helium and neon argon differs in that it is able to dissolve in water - at a temperature of 20 degrees in an amount of 3.3 ml in a hundred grams of liquid. But in a number of organic solutions, the gas dissolves better. The effect of electric current makes it glow, so it has become widely used in lighting equipment.

Biologists have discovered another useful property that argon possesses. This is a kind of environment where the plant feels great, which is proved by experiments. So, being in an atmosphere of gas, planted seeds of rice, corn, cucumber and rye gave their sprouts. In another atmosphere, where 98% is in argon and 2% in oxygen, a vegetable culture such as carrots, lettuce and onions grows well.

What is especially characteristic, the content of this gas in the earth's crust is much larger than other elements in its group. Its approximate content is 0.04 g per ton. This is 14 times the amount of helium and 57 times that of neon. As for the surrounding Universe, it's even larger, especially on different stars and nebulae. According to some estimates, there is more argon in space than chlorine, phosphorus, calcium or potassium, which are full on Earth.

Gas production

That argon in the cylinders, in which we often meet it, is an inexhaustible source. In addition, in any case, it returns to the atmosphere due to the fact that it does not change physically or chemically during use. An exception may be the cases of the consumption of a small amount of argon isotopes for the production of new isotopes and elements in the course of nuclear reactions.

In industry, gas is produced by dividing air into oxygen and nitrogen. As a result, gas is produced as a by-product. For this purpose, special industrial equipment of double rectification with two columns of high and low pressure and an intermediate condenser-evaporator is used. In addition, ammonia production waste can be used to produce argon.

Application area

The field of application of argon has several areas:

• Food industry;
• metallurgy;
• Scientific research and experiments;
• Welding works;
• electronics;
• Automotive industry.

This neutral gas is inside the electric buns, which slows the evaporation of the tungsten helix inside. Due to this property, a welding machine based on this gas is widely used. Argon allows you to reliably connect parts from aluminum and duralumin.

Gas was widely used to create a protective and inert atmosphere. This is usually necessary for the thermal treatment of those metals that are easily susceptible to oxidation. In an argon atmosphere, crystals grow well to produce semiconductor elements or ultrapure materials.

Advantages and disadvantages of using argon in welding

Regarding the field of welding, argon offers certain advantages. First of all, the metal parts do not so heat up during welding. This avoids deformation. Other advantages include:

• Reliable protection of the welded seam;
• The rate of argon welding is an order of magnitude higher;
• Process is easy to control;
• The welding can be mechanized or completely switched to automatic mode;
• The ability to connect parts from dissimilar metals.

At the same time, welding argon implies a number of shortcomings:

• When welding produces ultraviolet radiation;
• To use a high-amperage arc, quality cooling is necessary;
• Difficult work outdoors or draft.

Nevertheless, in the presence of so many advantages it is difficult to underestimate the importance of argon welding.

Precautionary measures

Care should be taken when using argon. Although the gas is non-toxic, it can cause choking, replacing oxygen or liquefying it. Therefore it is extremely important to control the amount of O ₂ in the air (at least 19%) using special instruments, manual or automatic.

Working with liquid gas requires extreme caution, since a low argon temperature can cause severe frostbite of the skin and damage to the eye shell. It is necessary to use glasses and overalls. Persons who need to work in the argon atmosphere should wear gas masks or other insulating oxygen devices.