Nowadays almost all smelted steel is processed in "ladle-furnace" (LF), where the steel is processed under refining conditions and brought to the desired temperature and chemical composition. Therefore, large amounts of refining slag are formed. Only in Russia there is about 1.4 million tons of slag exported to dumps annually. This slag cannot be processed by the schemes implemented in the industry, since the slag quickly turns into the tiniest dust during solidification and cooling. Such dust is easily aerated and carried by the wind for long distances; it pollutes soils, dissolves in ground, sedimentary and sewage waters. It also pollutes slag dumps that are suitable for processing for crushed stone.According to the data [1], the main reason of the LF slag disintegration is the polymorphic transformation of dicalcium silicate (2CaO⋅SiO 2 , C 2 S) (Figure 1), which is promoted by the high content of CaO in the slag. The high-temperature -modification is converted to a low-temperature -modification, with an increase in volume by 12%, which causes internal stresses in the mass of monolithic slag and also causes slag disintegration. It is noted that even a small amount of -C 2 S (about 4 wt.%) may be enough for decomposition.It is noted [1][2][3][4][5] that there are 4 ways to prevent the slag decomposition:1. The slag quenching ( -C 2 S receives the ability to maintain its qualities in the temperature range from 25 to 700 ∘ C);2. The borate addition (a partial substitution of SiO 4 4− ions in the C 2 S structure by BO 3 3− ions, which prevent the transformation of -C 2 S into -C 2 S);

There are millions of tons of solid waste residues accumulated in present-day alu- In some other works, solutions for the processing of red mud are presented either by reduction melting using the smelting furnace [4][5][6] or rotary furnace with subsequent processing by the Bayer process and enrichment [6]. Some works also indicate that at the end of pyrometallurgical conversion there are two products -the foundry iron and slag which can further be used in the alumina or cement clinker production.However, abundant impurities in the red mud prevent the production of high-quality iron and alumina concrete. In particular, a pig iron may contain a considerable amount