Metals are a group of elements that possess such unique properties as electrical conductivity, high heat transfer, positive resistance coefficient, characteristic gloss and relative ductility. This type of substance is simple in chemical compounds.
Group classification
Metals are among the most common materials that are used by mankind throughout its history. Most of them are in the middle layers of the earth's crust, but there are those that are hidden deep in the mountain deposits.
At the moment, metals occupy most of the periodic table (94 of 118 elements). Of the officially recognized, it is worth noting the following groups:
1. Alkaline (lithium, potassium, sodium, France, cesium, rubidium). Upon contact with water, they form hydroxides.
2. Alkaline earth (calcium, barium, strontium, radium). They are distinguished by density and hardness.
3.
Lungs (aluminum, lead, zinc, gallium, cadmium, tin, mercury). Due to their low density, they are often used in alloys.
4.
Transitional (uranium, gold, titanium, copper, silver, nickel, iron, cobalt, platinum, palladium, etc.). They have a variable oxidation state.
5.
Semimetals (germanium, silicon, antimony, boron, polonium, etc.). In their structure they have a crystalline covalent lattice.
6.
Actinides (americium, thorium, sea anemone, Berkeley, curium, fermium, etc.).
7.
Lanthanides (gadolinium, samarium, cerium, neodymium, lutetium, lanthanum, erbium, etc.).
It is worth noting that there are metals in the earth's crust and those that are not defined in groups. These include magnesium and beryllium.
Native compounds
In nature, there is a separate class of crystal chemical codification. These elements include native metals. These minerals are not interconnected in composition. Most often, native metals in nature are formed as a result of geological processes.
In a crystalline state in the earth's crust, 45 substances are known. Most of them are extremely rare in nature, hence their high cost. The proportion of such elements is only 0.1%. It is worth noting that finding these metals is also a laborious and expensive process. It is based on the use of atoms with stable shells and electrons.
Native metals are also called noble. They are characterized by chemical inertia and stability of compounds. These include gold, palladium, platinum, iridium, silver, ruthenium, etc. Most often, copper is found in nature. Iron in its native state is present mainly in mountain deposits in the form of meteorites. The rarest elements of the group are lead, chromium, zinc, indium and cadmium.
Basic properties
Almost all metals under normal conditions are hard and resistant. The exception is France and mercury, alkali metals. The melting point for all elements of the group is different. Its range ranges from -39 to +3410 degrees Celsius. The most resistant to melting is tungsten. Its compounds lose their resistance only at temperatures above +3400 C. Lead and tin should be distinguished from easily melted metals.
Elements are also divided according to density (light and heavy) and ductility (hard and soft). All metal compounds conduct excellent current. This property is determined by the presence of crystal lattices with active electrons. The maximum conductivity is copper, silver and aluminum, slightly less - sodium. It is worth noting the high thermal properties of metals. Silver is considered the best heat conductor, and mercury is the worst.
Metals in the environment
Most often, such elements can be found in the form of compounds and ores. Metals in nature form sulfites, oxides, carbonates. To purify the compounds, it is first necessary to isolate them from the composition of the ore. The next step will be alloying and final processing.
In industrial metallurgy, black and non-ferrous ores are distinguished. The former are based on iron compounds, the latter on other metals. Precious metals are platinum, gold and silver. Most of them are in the earth's crust. However, a small proportion also occurs in seawater.
There are noble elements even in living organisms. A person contains about 3% of metal compounds. To a large extent, sodium and calcium are in the body, which act as an intercellular electrolyte. Magnesium is necessary for the normal functioning of the central nervous system and muscle mass, iron is good for blood, copper - for the liver.
Finding metal compounds
Most elements are located under the topsoil everywhere. The most common metal in the earth's crust is aluminum. Its percentage varies within 8.2%. Finding the most common metal in the earth's crust is not difficult, as it occurs in the form of ores.
Iron and calcium are less common in nature. Their percentage is 4.1%. Next are magnesium and sodium - 2.3% each, potassium - 2.1%. The remaining metals in nature occupy no more than 0.6%. It is noteworthy that magnesium and sodium can equally be mined both in land and in sea water.
Metal elements in nature are found in the form of ores or in a native state, like copper or gold. There are substances that need to be obtained from oxides and sulfides, for example, hematite, kaolin, magnetite, galena, etc.
Metal production
The procedure for extracting elements is reduced to the extraction of minerals. Finding metals in nature in the form of ores is the simplest and most common process in a wide industry. To search for crystalline deposits, special geological equipment is used that analyzes the composition of substances on a specific plot of land. Less commonly, the presence of metals in nature is reduced to a banal open-underground method.
After mining, the enrichment stage begins when an ore concentrate is separated from the initial mineral. To distinguish the elements using wetting, electric current, chemical reactions, heat treatment. Most often, the extraction of metal ore occurs as a result of melting, that is, heating with reduction.
Aluminum mining
This process is engaged in non-ferrous metallurgy. In terms of consumption and production, it is a leader among other sectors of heavy industry. The most common metal in the earth's crust is very popular in the modern world. In terms of production, aluminum is second only to steel.
Most of this element is used in the aviation, automotive and electrical industries. It is noteworthy that the most common metal in the earth's crust can be obtained by the "artificial" way. Such a chemical reaction will require bauxite. Alumina is formed from them. By combining this substance with carbon electrodes and fluoride salt under the influence of electric current, pure
aluminum ore can be obtained
.The leading country among the manufacturers of this component is China. Up to 18.5 million tons of metal are smelted there annually. The leading company in a similar rating for aluminum production is the Russian-Swiss association UC RUSAL.
Metal application
All elements of the group are distinguished by strength, impermeability and relative resistance to temperature effects. That is why metals are so common in everyday life. Today, electric wires, resistors, appliances, household items are made from them.
Metals are ideal structural and instrumental materials. In construction, pure and combined alloys are used. In engineering and aviation, the main compounds are steel and stronger bonds.