Basics for the development of a rational composition of the main magnesian slags and technological methods for their formation according to the periods of BOF bath blowing and the periods of smelting in EAF are the results of fundamental studies of the slags physicochemical properties. Implementation in the converter shop of OJSC “EVRAZ NTMK” of a developed set of technological methods of magnesian slags formation in the main period of blowing and a wearresistant skull on the basis of magnesian final slags ensured record durability of converter linings. These slags have low aggressive effect on the lining of converters, while maintaining high refining properties. The durability of the converters’ lining exceeds 7000 heats, while maintaining high technological and technical-economic indicators of the process. During heats of low manganese cast irons in 350-metric ton heavy converters of JSC “EVRAZ ZSMK” under magnesian slags, the features of slag formation and changes in chemical composition of the slag were studied by the periods of the BOF bath blowing. During the process stage of phosphorous cast irons in 300-metric ton BOF at JSC “ArcelorMittal Temirtau”, a set of technological methods was developed for the formation of magnesian slags of the recommended chemical composition by the periods of phosphorus cast irons blowing and wear-resistant skulls based on final magnesian slags of moderate basicity. The implementation of the developed technological methods ensured the lining stability of BOF of more than 5 000 heats while maintaining high technological, technical and economic indicators of phosphorous process stage. In the EAF shop of PJSC “Seversky Pipe Plant” a technology for the formation of magnesian slags of rational composition was developed over the smelting periods in EAF-135. Introduction of the technology ensured the record resistance of the refractory lining of the furnace up to 1900 heats per campaign and high level of technological and technical-economic indicators of the process.

The authors have made an analysis of necessity to improve the composition of the existing structural materials for critical purposes in the direction of creating metal matrix materials, which combine a highly plastic metal base and refractory high-strength high-modulus fillers. For iron matrix alloys, dispersed yttrium oxide (Y2O3 ) particles are preferred because of their stability at pyrometallurgical process temperatures and inertness to alloy components. The technology of obtaining new materials by introducing dispersed particles into a liquid melt during casting using a centrifugal casting machine to obtain a hollow (pipe) billet is considered. The possibility of increasing the mechanical and operational properties of metal matrix materials in comparison with monomaterial is shown. The article describes results of the thermodynamic modeling of high-temperature processes occurring in the yttrium oxide - metal matrix (melt) system. Modeling was carried out using the FactSage software package. A composition corresponding to 12Cr18Ni10Ti steel was used as the modeling composition of the matrix material. The calculations were made according to the ratio of 1 g of yttrium oxide additive per 100 g of matrix metal melt. From the simulation results it is possible to conclude that the introduced dispersed yttrium oxide powder does not interact with the alloy components, does not dissociate, and does not undergo allotropic transformations. The expediency of conducting experiments on the production of centrifugal castings using yttrium oxide as a hardening phase with the aim of a possible increase in radiation resistance is shown. Directions are indicated for developing the most effective technology for creating metallic materials based on an iron matrix dispersed-hardened by yttrium oxide.

In laboratory conditions, influence of modes of welding with subsequent isothermal holding on quality parameters of welded joint was studied on rail steel samples. Samples were welded with pulses of alternating electric current after welding. Welding was carried out on MS-2008M resistance butt welding machine with a number of alterations of control actions. To measure temperature of the metal in heat affected zone (HAZ), chromel-alumel thermocouples were used. Collection and processing of data from thermocouples was carried out using TEMPOL measuring complex. Temperature of the weld (where it is not possible to install a thermocouple) was measured using HotFind-D thermal imager. Experimental results and physicomechanical properties of the samples are presented: HB hardness, HAZ length, yield strength, tensile strength, ultimate elongation, contraction ratio, and presence of non-metallic inclusions in weld metal. Deviations of hardness were calculated in comparison with the requirements established by GOST R 51685 – 2013 state standard on the surface of samples’ welded joints: decrease-increase and total deviation of hardness. Method of resistant butt welding is proposed, which makes it possible to obtain welded joint of items produced of rail steel with a uniform distribution of hardness and small zone of thermal influence. Dependence of microhardness on volume fraction of structural components was determined. Models of impact of pulsed contact post-welding heating parameters on lowering hardness of weld metal compared to the base metal and on the extent of heat-affected zone were constructed. The proposed method allows us to adjust structure of metal welded joints of rails without additional local heat treatment.

Analysis of air pollution by pollutants, sources of pollution, types of economic activity, and administrative areas in the city of Novokuznetsk over 5 years was carried out. The largest share in the city air emissions is accounted for: CO – 61.8 %; SO₂ – 17.4 %; solids – 11.3 %; NO₂ – 5.9 %; CH₄ – 1.8 %. Dynamics of gross emissions by years is shown. Planned implementation of the approved measures of the national project Ecology will make it possible to reduce air pollution in the city by more than 20 % by 2024, which corresponds to the federal project Clean Air. According to planes of the city industrial enterprises, environmental programs have been prepared, with monitoring by environmental specialists from the city administration and public control. Various measures were taken: automatic stationary posts were put into operation to monitor air pollution in real time; mobile laboratory was acquired to measure urban air. To improve waste management in the city, separate collection projects were implemented. Environmental assets exist and develop in the city, which ideas and projects find common understanding and form ecological attitude of the urban community. Trends in gross emissions of pollutants into the atmosphere of Novokuznetsk are shown for the period of 2014 – 2018; refinements and explanations of the observed trends are given.

The article presents results of testing semi-coke as a carbon reducing agent in the production of manganese and silicon alloys. The fundamental possibility of using semi-coke in carbon part of the charge as a basic reducing agent for the production of ferrosilicon manganese is established. It is noted that the new reducing agent in its pure form works worse than in the mixture with coal. The greatest synergistic effect in the production of ferrosilicon manganese was achieved during the interaction of semi-coke with coal, while the following indicators were obtained: maximum furnace productivity of 43 t/day, maximum extraction coefficient of 87.9 %, and minimum specific dust formation of 49 kg/t of alloy. In the production of ferrosilicon the use of a new reducing agent did not give a significant positive effect, due to its low structural strength. It was revealed that the structure and type of the reducing agent affect the furnace performance: when using a reducing agent with a higher reactivity in the charge, it is possible to obtain higher furnace performance. In the production of ferrosilicon, a change in the specific dust generation is closely related to the level of daily production and specific energy consumption and can serve as an indicator of the furnace operation. The furnace performance, ceteris paribus, is determined by the amount of useful power input. With an excess of carbon in the charge an increase in useful power leads to a slight increase in the furnace performance, but at the same time, the energy consumption and specific dust formation significantly increase. It is shown, that the influence of technological factors on the technical and economic indicators of melting is determined by the degree of electrode seating in the furnace.

One of the most problematic points in technology for storing ore enrichment waste materials with hardener admixture into underground mined space and tailing dumps are the tailings of hydrometallurgical plant (HMP). They are supplied through a slurry pipeline to the tailing dump in form of pulp with solid to liquid mass ratio of 1:2. Liquid phase of the pulp after gravity separation and clarification in tailing dump is returned to technological cycle of HMP. Storage technology under consideration has several disadvantages: high nonrecurrent capital costs for construction of tailing dump at full design capacity; high probability of harmful chemicals migration into groundwater if protective shields of the base or sides of tailings are damaged. The authors have used data from literature and patent documentation considering storage parameters, laboratory and production experiments, physical modeling and selection of compositions of hardening mixtures. Analytical studies, comparative analysis of theoretical and practical results by standard and new methods were performed. Possibility of using hardening mixtures with adjacent production wastes used as binders was established. Optimal composition of ingredients per 1 m3 of hardening mixture is proposed as follows: 1350 – 1500 kg of HMP tailings; 50 - 70 kg of binder (cement); 350 liters of mixing water. Proposed technology of ore enrichment waste storage into underground mined space and tailings with hardener admixture application allows using underground mined space at the enterprise production capacity of 1,500 thousand tons per year to store 50 – 55 % of tailings, and store the rest wastes cemented by binding material in repository. When filling the entire area of the tailing dump mirror of 10 m height with cemented tails and HMP capacity of up to 1.5 million tons per year, its operation life is extended by 50 years.

Using the methods of modern physical materials science, structuralphase states and tribological properties of 12Kh18N10T steel, subjected to electroexplosive alloying with titanium and boron and subsequent electron-beam processing in various modes depending on electron beam energy density, exposure pulse duration and their quantity have been analyzed. It has been established that electroexplosive alloying of steel with titanium and boron leads to formation of surface layer with multiphase submicro-nanocrystalline structure, characterized by presence of micropores, microcracks, and microcraters. Complex processing, combining electroexplosive alloying and subsequent irradiation with high-intensity pulsed electron beam, leads to formation of 60 μm thick multiphase submicro-nanocrystalline surface layer. It is shown that phase composition of surface layer of steel is determined by mass ratio of titanium and boron during electroexplosive alloying. Microhardness of modified layer is defined by relative mass fraction of titanium borides in surface layer and can be more than 18 times higher than microhardness of steel in its initial state (before electroexplosive alloying). Modes of complex processing have been determined at which surface layer containing exclusively titanium borides and intermetallic compounds based on titanium and iron is formed. The maximum (approximately 82 % by weight) titanium boride content is observed when steel is processed at regime with the highest mass of boron powder in the sample (mB = 87.5 mg; mTi /mB = 5.202). With decrease in mass of boron powder, relative content of borides in surface layer of steel decreases. It was found that integrated processing of steel is accompanied by sevenfold increase in microhardness of surface layer, wear resistance of steel increases by more than nine times.

Volumetric problem of determining stress-strain state of metal in deformation zone during forming of three section billets from the slab by separating collars of grooved strikers on the unit of combined continuous casting and deformation was set and solved. The expediency of using such unit was justified for longitudinal division mation are given for St3sp steel. The solid-state finite elements used in calculation of stress-strain state of metal in deformation zone and dimensions of the grid are described. The results of calculation of stress-strain state of metal in deformation zone were obtained by solving the problem of elasticity by the finite element method in volumetric formulation. The results of calculation of displacements and stresses in deformation zone are given in form of graphs and tables by working surfaces in four cross sections and are presented for characteristic points. Values and regularities of distribution of axial displacements in width and length of deformation center were determined during introduction of strikers separating collars into continuously cast slab in production of three section steel billets on the unit of combined continuous casting and deformation.

Processing of bulk materials used in metallurgical industry to obtain necessary grades of size requires application of crushing machines, including a single-roll type. Indicators of crushing process are degree and efficiency of crushing. Degree of crushing is estimated by the ratio of size of initial crushed and resulting pieces, which depends on size of the gap between a roll and a fixed jaw. The Siberian State Industrial University has patented, designed and manufactured a pilot unit, which is a single-roll crusher with block stop on the roll to study crushing process. A series of experiments on different samples (in shape, size and strength) crushing was carried out on the developed unit. Technique of the experiment and the design of a single-roll crusher with block stop on the roll were described. Results of destruction of the samples of isotropic material made of sand-cement mixture of regular (spherical) shape are presented. Samples from isotropic material allow comparison of analytical conclusions of determining position of the plane of action of maximum tangential stresses with experimental data. Samples of anisotropic material (for example, ferroalloy) were also destroyed. It was experimentally determined that the larger is clearance between the roll and the fixed jaw, the larger is the size of fraction of finished product and over-grinding is less than after crushing the same piece with a smaller clearance. The degree of crushing in a single-roll crusher with block stop on the roll cannot be equal to 4 or more. It was proved that destruction of isotropic materials occurs along the plane of action of maximum tangential stresses. Anisotropic materials are destroyed, depending on size of clearance between a roll and a jaw, both on the plane of action of the maximum tangential stresses and on the planes of least resistance.

Possibility of selective solid-phase reduction of iron from oolitic ore has been experimentally confirmed. Solid phase reduction was carried out at temperatures of 850 and 1000 °C in CO atmosphere and in the mixture with solid carbon. Distribution of iron and phosphorus was investigated with scanning electron microscope. It was found that at temperature of 1000 °C minimum amount of phosphorus (up to 0.3 %) is transformed into the metallic phase at reduction by carbon monoxide. Upon reduction in mixture of ore with carbon, phosphorus content in metal phase reaches 1.0 – 1.3 % evenat temperature of 850 °C. Thermodynamic modeling of the processes occurring during reductive roasting of oolitic ore was carried out depending on temperature (1000 – 1400 K) and amount of carbon in the system. It is shown that reduction temperature and degree of phosphorus reduction vary depending on ratio of CO and CO2 in the gas phase. At temperatures below 892 °C, phosphorus is not reduced and all iron is in metal phase. With an increase in amount of carbon in the system, phosphorus appears in metal phase. With an excess of carbon in the system, all phosphorus is in metal phase at temperature of 892 °С. Thus, with a certain amount of carbon in the system and, correspondingly, with a certain ratio of CO and CO2 in gas phase, selective reduction of iron is possible without phosphorus reduction even at temperature of 1100 °С. Comparison of experimental results with results of thermodynamic calculation confirms possibility of se selective reduction of iron without phosphorus reduction only by carbon monoxide.

Thermo-gravimetric method was used to determine the temperature of crystallization onset of alloys of the Fe – Ni – Cr – C – Si system depending on concentration of chromium and nickel. It was shown that complex ferroalloys containing 0.2 – 21.0 % Ni (at Cr = 25 – 28 %); 0.5 – 45.0 % Cr (at Ni = 10 – 11 %); 2.0 % C and 0.3 % Si, iron, and impurities belong to the category of low-melting alloys and have rational values (1320 – 1400 °C) of crystallization temperatures in terms of their use for steel processing in the ladle. An increase of the chromium content to more than 45 % in these alloys is accompanied by an intense increase of their temperatures of the crystallization onset.