The world's consumption of metals is increasing: according to different estimates, it is up to 1 billion tons per year. Consequently, metal production, in other words mining, is also increasing. The natural resources of metals, especially rare and noble ones, are not so rich. Therefore, the development of technologies of how to recover them from the ground is becomes very important.
Consumption and Resources
Some metals are found in the Earth's crust in a relatively large amount, for example, about 9% is aluminum, slightly less than 5% is iron, and about 2% is magnesium. But these metals are few, and the shares of important elements are mostly hundredths, and even thousandths of a percent. The natural resources of noble (gold, silver, platinum) and rare metals (molybdenum, tungsten, lithium, Gaul, etc.) are especially scarce.
Meanwhile, all these materials are needed by society in large quantities. Metals today are key structural materials that are applied in all spheres of consumption and economic industries. About 90% of all consumed metals is steel, about 3% is aluminum, and copper, zinc, and lead are also quite significant. The production of the above-mentioned metals amounts to millions of tons per year, while the more rare non-ferrous metals are produced in thousands of tons (magnesium, titanium, nickel, cobalt, molybdenum, tungsten), tons (selenium, tellurium, gold, platinum) and even kilograms (iridium, osmium).
The use of metals in different fields is determined by their physicochemical properties. For example, iron and steel are solid and durable, and these are important materials for construction. Aluminum, on the other hand, is rather mild and malleable, has good heat conductivity, has strength at low temperatures, and is therefore used, in particular, in the construction of aircrafts. Plastic and electrically conductive copper has found its use in the production of electric cables, power engineering. And so it is clear about precious metals: gold and silver are used mainly in the jewelry business.
Experts estimate that the consumption of metals is increasing unswervingly. Metallurgy products from around the world are about 3/4 of the gross national product (about 75%). The main producers and consumers of metals are the US, Japan, China, Russia, Germany, Ukraine, France, Italy, Great Britain and other countries.
Metals are extracted by means of extracting valuable components from ore and melting the recovered raw materials into a pure material. The processing of ores takes place on a large scale around the world. Metallurgical enterprises work with three components: raw materials, concentrated material (metal oxide or sulphide) and waste. In order to obtain pure metal from concentrate, ore must be separated by a physical, chemical or electrolytic method. Ore sometimes contains several metals, in which case the waste of one industrial process may become the raw material for another.
Mining in the mountains is not a compulsory process today, because in some cases metal can be leached. This method can be used to dissolve a mineral and obtain a mineral-enriched solution.
Blast furnaces are used in order to produce iron from ores and alloys based on it. The temperature in such furnaces is more than 1000°C, allowing iron to be released from ore and to float iron. Depending on the progress of this process, it is possible to obtain steel-making pig iron and cast iron.
Steel is stronger than cast iron and more efficient as a construction material. Steel is melted in special steel-making furnaces, where metal is in its liquid state. At the same time, several methods of obtaining steel are highlighted: oxygen-converter, open-hearth and electric melting, in which induction and arc furnaces are used.
The essence of the first method is to blow cast iron from the converter. Oxygen oxidizes the impurities of cast iron, and it becomes steel. The open-hearth process is melting of the reflective furnace on the principle of heat regeneration. These technologies were widely used not only throughout the world but also in Russia in the 19th century, and played an important role in the Great Patriotic War. Today open-hearth furnaces are used less and less, but they still allow melting cast iron of any composition and obtaining high-quality steel. The third method, electric furnace steel-making, is the most common technology in our day.
AC and DC arc furnaces and induction furnaces are used in this method. High-quality steels are melted in such furnaces. They make it possible to remove non-oxidizing slugs from metals, to clear metal, to obtain steel with a lower sulfur content, etc.
Pyrometallurgical methods with reduction or oxidizing melting, and also hydrometallurgical methods with transfer of metals into soluble compounds and subsequent leaching, are used in non-ferrous metallurgy. There are also sometimes metal-thermal processes that use other metals with high affinity for oxygen as reducing agents of the produced metals, as well as the chemical-thermal method, cyanidation and chloride-sublimation.
For example, copper is generally produced in a pyrometallurgical way (about 90% of the total copper production) from sulphide ores. Other valuable metals are also extracted from the same ores. The main stages of copper production are: preparation of ores by enrichment and roasting, melting, conversion to black copper, refining (cleaning) with fire and the electrolytic method. Aluminum is produced from ore raw materials by the electrolytic method. The production of valuable metals such as tungsten or molybdenum may be more complex, with the use of special aggregates and equipment, and the production of these elements is also based on pyrometallurgical and hydrometallurgical processes.
White metallurgy is not a new type of metallurgy, but a new standard for the operation of metallurgical industries.
The white metallurgy was presented in Russia in 2010 at Chelyabinsk Pipe Rolling Plant (ChTPZ) upon commissioning of "Height 239", a new workshop for the production of large diameter pipes. It was traditionally thought that the production of pipes related to the steel industry, but CHTPZ destroyed all such stereotypes. A new approach to the organization and design of production space, building the working environment and, most importantly, to creating a unique corporate culture centered on the human personality, was formed and applied for the first time in the country based on the company’s newest high-tech production. The principles of white metallurgy are implemented not only in the new enterprises of the ChTPZ group, but also in the workshops with 70-and even 80-year old history: there is a system of constant improvements, equipment is modernized, the latest technologies are used that allow working in overalls of any color, including white; highly skilled employees work here. The factory generally encourages workers to seek education, new skills and professions and creates the conditions for doing so.
It is now believed that products and technologies, as well as the qualifications of the employees of enterprises that support the white industry standards, meet the highest quality requirements.