One of the main sectors of the national economy is metallurgy. It provides raw materials to many other industries. Ferrous and non-ferrous metals are needed almost everywhere. And the prices for these raw materials are growing every day. Energy prices, of course, have a significant impact on the cost of metallurgical products. But an important role in the formation of prices is also played by production waste.
And in metallurgy there are especially many of them. They occupy large areas and pollute air, water and soil with toxic compounds. And at the same time, the costs of their placement, storage and transportation significantly affect the cost of production of metallurgical enterprises. But these products contain many valuable elements that can be used as secondary raw materials. And with the master's approach, such waste from metallurgical production can be turned into a source of income.
These wastes result from the smelting of steel, cast iron or ferroalloys. And the content of various useful components, including iron, may be even higher in them than in the same natural ores. And due to poor knowledge of the composition and properties of sludge, there is a problem with their reuse.
Take at least steelmaking slag. Such recyclable industrial wastes at many metallurgical plants and plants are converted into enriched slag. For this, “dry” magnetic separation of products obtained after slag crushing is used. A useful product obtained after such processing is considered to be larger kings of metal, as well as intergrowths of metal and silicate glass. Iron in the composition of enriched slag is relatively small. And as a result of enrichment at sinter plants, about 40 kilograms of metal is obtained from a ton of slag. The remaining production waste, which contains only small inclusions of iron or its oxides, is sent to the dump.
But there is also a more efficient technology for enriching steelmaking slag. With its help, three products can be obtained from these wastes. The first of these is a metal product. It turns out about 10% of the total mass of slag. It, in addition to metallic iron, contains minor impurities of glass, silicates and carbonates. It is briquetted and sent for secondary smelting. The second is a calc-iron oxide product. It makes up about 22% of the total. There is not much iron in this product. For the most part, it consists of various minerals. These are wustite, magnetite, maghemite, goethite, hematite, hydrated lime, iron and calcium carbonates, as well as magnesium and calcium ferrites. This product can be used as a high-quality charge material in the production of fluxed iron ore sinter. And the residue, which is about 68%, falls on the silicate product. Its main part is made up of minerals: silicates, spinel, tridymite, silicate glass and lime hydration products. These production wastes are also not wasted. A silicate product is used mainly in construction, for the production of cement or other binders.
You can also take ferromanganese slag production, which contains many valuable components. These are the kings of ferromanganese and metallic iron, silicates, hydroxides, oxide aggregates, manganese and iron carbonates, silicate glass and its crystallization products. Scientists have developed a method by which dry gravitational enrichment of these slags is carried out. As a result, these production wastes make it possible to obtain three products.
The first of these is ferromanganese concentrate. From the entire mass of slag it can be obtained up to 17%. This product contains magnetic and non-magnetic parts of iron, manganese, iron cohenite, various alloys with a variable content of manganese and iron, as well as their hydroxides and oxides. You can use this product for the production of ferromanganese.
The second product is silicate sand. Half of the total mass of slag falls on it. Silicate sand consists mainly of quartz, cristobalite, tridymite, glass and silicates. It can be used to produce silicomanganese or use it as a building material.
And the remaining 33% are clay-carbonate dust. It consists of finely ground silicates, carbonates, glass and other minerals. This dust is used for the production of cement. There are many more types of waste that can benefit people.