Scientists from NUST MISIS have developed and patented a new method for secondary smelting of pig iron from metallurgical waste, i.e. screenings and sludge. This was reported to RT in the press service of the university. The results of the study are published in the journal Metallurgist (Q2).

In the production of direct reduced iron, iron-rich by-products are formed, the so-called screenings and sludges. As a rule, such metallized materials are formed in the form of briquettes using various binders and then sent for secondary remelting.

However, briquettes from small metal fractions can currently be melted down only at large ferrous metallurgy plants. In conventional electric arc furnaces, which are widely used in small metallurgical enterprises, such raw materials cannot be processed, the authors of the study note.

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MISIS scientists have found a solution to this problem by selecting such a composition of briquettes and melting conditions under which this type of waste can be recycled even in small plants. Such electric smelting industries often face a shortage of raw materials - they are mainly engaged in the melting of scrap metal and the production of finished products, such as, for example, metal fittings. While large metallurgical plants specialize in the smelting of pig iron from ore and the production of large-capacity rolled steel.

The developed technology will help small metallurgical plants to find additional sources of raw materials for the production of construction and other metal products. In the course of the study, experimental melting was carried out and the efficiency of the technique was confirmed. Empirically, experts have determined that briquettes with the addition of 15% of the fine metallized fraction give the best result.

Another advantage of the new method is that to load the waste into the furnace for melting, it is not necessary to add special fluxing additives to them, which reduce the melting point.

"In the course of pilot experiments on the implementation of the claimed method, the yield of iron in cast iron from waste was over 93%," said Pavel Chernousov, associate professor of the Department of Energy Efficient and Resource-Saving Industrial Technologies at NUST MISIS, in an interview with RT.

The cast iron obtained from briquettes meets GOST standards and can be used for smelting ferrous metals and alloys, the authors of the study note.

"The cast iron obtained from these briquettes meets the requirements of GOST 4832-95 and can be applied to L4 cast iron, class A, category 4. This opens up new opportunities for the production of primary ferrous metal and improving the efficiency of metallurgical production processes," added Pavel Chernousov.