Preparation of metals and their use

Despite the fact that art-created materials are increasingly being used in industry and everyday life, it is not yet possible to abandon the use of metals. They have a unique combination of properties, and alloys allow maximum use of their potential. In what areas is the production and use of metals?

Characteristics of a group of elements

Metals are understood as a set of inorganic chemical substances with characteristic properties. Typically, they include the following:

• High thermal conductivity;
• Plasticity, relative ease of machining;
• Relatively high melting point;
• Good electrical conductivity;
• Characteristic "metallic" luster;
• The role of the reducing agent in the reactions;
• High density.

Of course, not all elements of this group possess all these properties, for example, mercury at room temperature is liquid, gallium melts from the heat of human hands, and bismuth can hardly be called plastic. But in general, all these traits are traced in the aggregate of metals.

Internal classification

Metals are conditionally divided into several categories, each of which combines elements that are closest to each other in various parameters. There are the following groups:

• Alkali - 6;
• Alkaline earth - 4;
• Transitional - 38;
• Lungs - 7;
• Semimetals - 7;
• Lanthanides - 14 + 1;
• Actinides - 14 + 1;

Outside the groups there are two more: beryllium and magnesium. Thus, at the moment, among all the open elements, 94 scientists are referred to as metals.

In addition, it is worth mentioning that there are other classifications. According to them, noble metals, platinum group metals , post-transition, refractory, black and color, etc. are considered separately , etc. This approach makes sense only for certain purposes, so it is more convenient to use the generally accepted classification.

History of receipt

Mankind throughout its development has been closely associated with the processing and use of metals. In addition to being the most common elements, they could be used to manufacture different products only with the help of mechanical processing. Since there were no skills to work with ore, at first we were talking only about using nuggets. At first it was a soft metal, which gave the name to the copper age, which replaced the stone one. During this period, a method of cold forging was developed. In some civilizations, smelting became possible. Gradually, people have mastered the production of non-ferrous metals, such as gold, silver, tin.

Later the copper age came to replace the bronze age. It lasted about 20 thousand years and became a turning point for mankind, because it was during this period that it became possible to obtain alloys. There is a gradual development of metallurgy, methods of obtaining metals are being improved. However, in the 13th-12th centuries. BC. E. There was a so-called bronze collapse, which laid the foundation for the Iron Age. This is presumably due to the depletion of tin stocks. And lead and mercury, discovered at this time, could not become a substitute for bronze. So people had to develop the production of metals from ores.

The next period lasted for a relatively short time - less than a millennium, but left a bright mark in history. Despite the fact that iron was known much earlier, it was almost not used because of its shortcomings compared to bronze. In addition, the latter was much easier to obtain, while ore smelting was more labor intensive. The thing is that native iron is rare, so it's no wonder that the rejection of bronze occurred so slowly.

Importance of metal extraction skills

By analogy with how the ancestor of man first made a tool of labor, tying a sharp stone to a stick, the transition to a new material was as grandiose. The main advantages of metal products were that they were easier to make, and there was also the possibility of fixing. The stone does not have plasticity and malleability, so that any tools from it could only be done anew, they could not be repaired.

Thus, it was the transition to the use of metals that led to the further improvement of the tools of labor, the appearance of new objects of everyday life, ornaments, which it was impossible to produce before. All this gave impetus to technical progress and laid the foundation for the development of metallurgy.

Modern methods

If in ancient times people were only familiar with obtaining metals from ores, or they could be satisfied with nuggets, then there are other ways now. They became possible due to the development of chemistry. Thus, there were two main directions:

• Pyrometallurgy. It began its development earlier and is associated with high temperatures necessary for processing the material. Modern technologies in this field also allow the use of plasma.
• Hydrometallurgy. This area deals with the extraction of elements from ores, waste, concentrates, etc. with the help of water and chemical reagents. For example, the method involving the production of metals by electrolysis is extremely common, also the method of carburizing is quite popular.

There is another interesting technology. The production of precious metals of high purity and with minimal losses became possible thanks to it. It's about refining. This process is one of the types of refining, that is, the gradual separation of impurities. For example, in the case of gold, saturation of the melt with chlorine is used, and platinum is dissolved in mineral acids, followed by isolation with reagents.

By the way, the production of metals by electrolysis is most often used if smelting or recovery is economically unprofitable. This is the case with aluminum and sodium. There are also more innovative technologies that make possible the production of non-ferrous metals, even from fairly poor ores without significant costs, but this will be discussed a little later.

About alloys

Most of the metals known in antiquity did not always meet certain needs. Corrosion, insufficient hardness, fragility, fragility, fragility - each element in its pure form has its drawbacks. Therefore, it became necessary to find new materials combining the advantages of the known ones, that is, to find ways to produce metal alloys. To date, there are two main methods:

• Casting. The melt of the mixed components is cooled and crystallized. It is this method that made it possible to obtain the first samples of alloys: bronze and brass.
• Pressing. A mixture of powders undergoes high pressure, and then sintered.

Further improvement

In recent decades, the most promising seems to be the production of metals using biotechnology, primarily with the help of bacteria. It has already become possible to extract copper, nickel, zinc, gold and uranium from the sulphide raw materials. Scientists hope to connect microorganisms to such processes as leaching, oxidation, sorption and precipitation. In addition, the problem of clearing deep wastewater is extremely topical, for it, too, are trying to find a solution that involves the participation of bacteria.

Application

Without metals and alloys, life would not be possible in the form in which it is now known to mankind. High-altitude houses, airplanes, dishes, mirrors, electrical appliances, cars and much more exist only thanks to a distant transition of people from stone to copper, bronze and iron.

Due to their exceptional electrical and thermal conductivity, metals are used in wires and cables for a variety of purposes. Gold is used to make non-oxidizable contacts. Due to its strength and hardness, metals are widely used in construction and for obtaining a variety of designs. Another area of application is the instrumental. Hard metal alloys and special types of steel are often used to make the working part, for example, the cutting part. Finally, precious metals are highly valued as a material for jewelry. So there are plenty of applications.

Interesting about metals and alloys

The use of these elements is so widespread and has such a long history that it is not surprising that various curious situations arise. They and just a couple of interesting facts and should be brought to the end:

• Prior to its widespread use, aluminum was highly valued. Cutlery, which when receiving guests Napoleon III, were made of this material and were the pride of the monarch.
• The name of platinum in Spanish means "silver." Such an unflattering name element was obtained in connection with the relatively high melting point and, consequently, the inability to apply it for a long time.
• In its purest form, gold is soft, and it can easily be scratched with a fingernail. That is why to make jewelry it is fused with silver or copper.
• There are alloys with a curious property of thermoelasticity, that is, the "memory" effect of the shape. With deformation and subsequent heating, they return to their original state.