This review considers the papers aimed to find an effective solution to the red mud utilization problem. Red mud or bauxite residue is a hazardous materials that are generating during production of alumina by the Bayer process. Depending on the composition of bauxite and the technology, production of 1 ton alumina forms from 0.9 to 1.5 tons of this waste. The global inventory of red mud is estimated at about 4 billion ton in 2015. The main quantity of bauxite residue is not processed, but pumped into land-based ponds and it leads to environmental pollution. In 2010 in Hungary a pond containing red mud were collapsed, freeing about 700 thousand m3 of liquid waste, as a result 10 people were died, about 350 houses were destroyed and significant regions were polluted. Red mud obtained by different plants has various chemical and phase compositions. Despite this fact the main components of red mud is iron-containing minerals, so bauxite residue can be considered primarily as a raw material for the metallurgical industry. This part of the review considers pyrometallurgical methods for of red mud treatment, including both methods of low-temperature reduction at temperatures of 1050 - 1200 °C and high-temperature reduction melting, as well as utilization methods of the resulting slags. These slag utilization methods can be used for extraction of alumina, titanium and rare-earth metals, obtaining building materials such as various cements, mineral wool and flux materials for metallurgy. Methods of alkali removing, drying and agglomeration of red mud also considered. It has been shown that the best ways of bauxite residue recycling are the pyrometallurgical methods with obtaining of iron-containing product and slag for the production of building materials or metallurgical fluxes. These techniques make possible to utilize a large amount of red mud with exception of additional waste formation. This is the first part in a series of three related reviews examining the world experience of red mud recycling by various ways.

The use of quartz for its low-temperature modification creates additional risks in the manufacture of molds in the part of their reduced crack resistance due to polymorphous transformations and in practice it often leads to cracking and even destruction of individual layers of the shell wall or the mold as a whole. Preliminary calcination of the covering material practiced in many foundries can somewhat reduce the negative consequence of dangerous polymorphic transformations of quartz. But at the same time, smooth heating of the molds to reduce the likelihood of their cracking, which is carried out in the support filler, contributes to an increase in duration of the technological process and in additional energy costs. Among the options for reducing the likelihood of cracking and the destruction of RP during their calcination, the most popular is replacement of pulverized quartz sand, as filler, with dispersed quartz sand of a polyfraction composition, disten-sillimanite, pulverized aluminosilicate, spherical corundum or fused quartz. However, all of them are quite expensive and do not meet modern challenges and resource saving requirements in foundry and metallurgical industries. In this connection, attention is drawn to the ceramic shards of shells of steel and aluminum investment casting on silica-based models. At present, the shards of spent ceramic shell molds for investment models is not used for recycling. This material is sent to the dump or used as a supporting filler of the flasks when the shells are formed therein. The conducted component chemical and phase analysis of the material has shown that in shards of ceramic shells formed after knocking out steel and aluminum castings from molds, in addition to quartz in the high-temperature phases of tridymite and cristobalite (base), there are up to 5 - 10 % of iron and iron scale and 3 - 5 % of aluminum and its oxides. The use of ceramic shell shards as a covering material excludes the repeated polymorphic quartz transformations during calcination and pouring of shapes that determine the change in volume, density, and change in types of material crystal lattices, which makes it possible to increase the fracture toughness and strength of the shells and to minimize discard of the resulting castings. Residual iron, aluminum and their oxides contribute to improving the processability of the mold. Experimental testing of the proposed recycling option in the conditions of current production has confirmed its effectiveness.

The review contains main directions in the development of modern steelmaking, hot rolling technologies and heat treatment aimed to follow increased requirements to seamless tubes for production of oil and gas under severe conditions. New targets of PJSC “Gazprom” in development of new resources have determined new technical requirements to pipes for low temperature application, resistant to hydrogen sulfide and carbon dioxide corrosion. Basic metal science approaches are given to develop new chemical compositions of high quality steels containing minimum of sulfur, phosphorous and solute gases. Corresponding heat treatment routes are determined for formation of martensitic microstructure in full wall section during quenching with subsequent high tempering for required combination of high strength and ductility. It was shown that optimal combination of high strength and toughness at 60 °C below zero can be achieved by alloying of chromium-molybdenum steel containing about 0.25 wt. % of carbon with strong carbon forming elements such as vanadium and niobium. Sustainability of these steels to stress sulfide cracking was achieved through grain refinement with microalloying by molybdenum in concentrations corresponding to strength grades that gives high hardenability and retards tempering of martensite. New compositions of corrosion resistant martensitic 13 % chromium steel were carried out that was resulted in required resistance to carbon dioxide environments with improved low temperature toughness and high strength. The authors present results of reconstruction of steel making and hot rolling production lines at JSC “Volzhskii Pipe Plant” providing the required quality of new products from continuously cast steel billets to finished tubes.

Analysis of literature and production data has shown that despite the significant improvement in quality of domestic rail products, achieved in the last decade due to fundamental technical re-equipment of rail production, there is a problem of increased rejection of rails for surface defects. Based on studies of influence of rail steel chemical composition on quality of rails produced by «EVRAZ ZSMK», there was established a significant effect of increasing copper content in the range of 0.07 - 0.15 % and of sulfur - in the range of 0.006 - 0.011 % in E76KhF steel to increase rejection caused by rail surface defects. Mechanism of the influence of these elements concentration in rail steel on finished rails quality was revealed. Decisive influence of ratio of pig iron and scrap in metal charge on copper and sulfur content in rail steel was evidenced - higher rate of cast iron in metal charge within 20 - 50 % contributes to decrease of copper concentration and increase of sulfur content. To justify optimal composition of the charge for rail steel melting in regard to rail products quality and technical and economic indicators of production, study of the effect of cast iron (liquid and solid) to scrap ratio in metal charge on basic parameters of furnaces’ operation was conducted. As a result, it was found that with an increase in share of both liquid and solid iron in metal charge, there are linear decrease in specific electricity consumption, increase in specific oxygen consumption according to parabolic law and a linear decrease in manganese content in furnace output. The obtained dependences of melting duration on ratio of charge components in metal charge indicates presence of prominent minimum, when using liquid iron in the range of 35 - 40 %, and when using solid iron - in the range of 30 - 35 %. Based on the regression equations, statistical model was constructed for the influence of metal charge composition on technical and economic performance of the melt charge in rail steel smelting, in which optimization parameters are: total cost, depending on the metal stock composition and performance of the shop for suitable billets produced by continuous casting. Application of the obtained model allows to develop reasonable recommendations on the optimal proportion of iron in the metal for current level of prices for materials and energy used in electric smelting, taking into account changes in the shop productivity.

The residual stresses in metals can lead to the defects in metals during their forming and to destruction of metal structures during their long-term operation. The resulting residual stresses during metal forming can be of plastic nature, as in the malleable metals, or caused by a slow irreversible creep at the increased temperatures and prolonged action of loads. In the viscoelastic mediums, it can be caused by the viscous parts of deformation that can accumulate when the body is deformed for a long period of time. The residual stresses also have an effect on the metals microstructure and can present inside and around the crystalline grains as the micro-residual stresses, which are called the hidden elastic stresses. Sometimes the residual stresses are called the eigenstresses by an analogy with the eigenfunctions, introduced by the mathematicians to denote the functions that correspond to the certain values (the eigenvalues) of parameters of the differential equation under the given boundary conditions. The concept of the internal stresses was proposed as a general concept for this type of stresses, created by the body itself; the term residual stresses is assigned to the case, when the internal stresses are caused by the irreversible deformation. In addition to the emergence of favorable system of residual stresses in the discs of malleable metals with a pronounced deformation hardening, there will also be a local increase in strength, provided that the Bauschinger’s effect does not negate the achieved advantages. The extreme values of residual stresses of a straight cylindrical steel rod (beam) during bending are studied below.

The article presents the results of a study of formation mechanism of magnesia-ferrite when heated siderites of the Bakal deposit with different iron oxide content in an inert and oxidizing atmosphere. It was established that in the case of firing in an inert atmosphere, the decomposition of siderite with high iron content begins at a lower temperature and the enthalpy of such decomposition is less. This effect can be explained by the different phase composition of the samples. The main phases formed under conditions of oxidative firing are hematite and magnesia-ferrite. The amount of hematite and magnesia-ferrite produced in the samples with different iron oxide content during firing in an oxidizing atmosphere is different. Siderite with high content of iron oxides contains more hematite in the firing products than magnesia-ferrite, and siderite with a low content of iron oxides contains more magnesia-ferrite in the firing products than hematite. Formed under conditions of oxidative firing magnesia-ferrites are solid solutions and differ in the degree of substitution of iron and magnesium ions. In siderites with high content of iron oxides, the degree of substitution of magnesium ions with iron ions is greater than in samples with a low content of iron oxides. Since the siderites of the Bakal deposit are poor ore formations, the considerable amount of magnesia-ferrite formed in them during firing makes it difficult to separate silicate and iron-oxide firing products by traditional enrichment methods. Wustite in the products of oxidative firing is not detected, because under these conditions it is in a metastable state and in the presence of a weakly oxidizing atmosphere is converted into magnetite. The scientific novelty is the explanation of the mechanism of siderite decomposition and the description of products of such decomposition. Understanding of the mechanism of decomposition of siderite from the Bakal deposit made it possible to develop the technology of reductive firing of siderite to facilitate separation of its products, and which consists in the regulation of the phase composition of silicate products of reductive firing, ensuring the collapse of magnesia-ferrite and output of iron oxide in a separate phase. The developed technology can be used to provide high-quality enrichment of siderite from the Bakal deposit.

Powder wire for surfacing of abrasive-wearing products of Fe - C - Si - Мп - Cr -Ni - Mo system (type A according to IIW classification) was developed and investigated. Studies in laboratory conditions were performed according to the following scheme: multilayer surfacing of the samples was carried out with preheating of plates up to 350 °C and subsequent slow cooling (after surfacing). Surfacing was made by ASAW-1250 welding tractor with manufactured cored wire in six layers on plates of 09G2S steel. Instead of amorphous carbon, carbon-fluorine-containing dust containing 21 - 46 % Al₂O₃ ; 18 - 27 % F; 8 - 15 % Na₂O; 0.4 - 6.0 % K₂O; 0.7 - 2.3 % CaO; 0.5 - 2.5 % SiO₂ ; 2.1 - 3.3 % Fe₂O₃ ; 12.5 - 30.2 % Cgen ; 0.07 - 0.90 % MnO; 0.06 -- 0.90 % MgO; 0.09 - 0.19 % S; 0.10 - 0.18 % P was introduced into the wire. The following powder materials were used as filler: iron powder PZhV1 as per GOST 9849 - 86, ferrosilicon powder FS 75 as per GOST 1415 - 93, high carbon ferrochrome powder F99A as per GOST 4757 - 91, carbon ferromanganese powder FMN 78(A) as per GOST 4755 - 91, PNK-1L5 nickel powder PNK-1L5 as per GOST 9722 - 97, ferromolybdenum powder FMo60 as per GOST 4759 - 91, ferrovanadium powder FV50U 0.6 as per GOST 27130 - 94, cobalt powder PC-1U as per GOST 9721 - 79, tungsten powder PVN as per PS 48-19-72 - 92. Studies of the deposited layer have shown that within the obtained limits, carbon, chromium, molybdenum, nickel, manganese and to a lesser extent vanadium simultaneously increase hardness of the deposited layer and reduce rate of wear of the samples. Increase in concentration of tungsten increases hardness of the deposited metal but reduces wear resistance. Low viscosity of matrix does not allow tungsten carbides to be kept on surface, as a result, wear occurs not according to the uniform surface abrasion scheme, but is reasoned by pitting high-strength carbide particles from the matrix, resulting in additional cracks formed in matrix, contributing to additional wear of matrix. Introduction of cobalt to the mixture composition does not have significant effect on hardness and abrasive wear of the deposited layer, which is associated with obtaining more viscous, but less solid matrix. In case of absence of solid particles of carbides embedded in matrix, the effect of introduction of cobalt is negative. According to the results of multivariate correlation analysis, dependences of hardness of the deposited layer and its wear resistance on mass fraction of elements included in flux-cored wires of the Fe - C - Si - Mn - Cr - Mo - Ni - V - Co system were determined.

The influence of long-term operation at 515 °C on structure and properties of 09Cr18Ni9 steel was investigated. Structure and phase composition were obtained using optical and scanning electron microscopy. The phase composition of the steel in equilibrium state was determined by thermodynamic modeling in the software package Fact-Sage. As a result of the study, it was found that during the operation at 515 °C with a duration of 195,000 h, the structure changes occurred in the 09Cr18Ni9 steel with the formation of secondary phases, initiated by the release of elements with limited solubility from the supersaturated solid solution. The following secondary precipitates in structure of the solid solution of austenite presented: Cr23C6 chromium carbide, ferrite (a), G-phase. Based on comparison of the thermodynamic modeling results and on experimental determination of the phase composition, it was established that the steel structure is in a state close to equilibrium. The mechanism of structural transformations course and sequence of the secondary phases’ formation were revealed and described. At the initial stage, chromium carbide is formed, then a-ferrite is formed near the carbides, and then G-phase is formed. Results of the tests for impact strength and static elongation have shown that the change in phase composition in process of thermal aging leads to embrittlement of the steel - a reduction in ductility and impact energy. Fractografic studies of fracture surfaces of the samples have shown that the decrease in plasticity during long-term high-temperature operation is associated with softening of the grain body and strengthening of the boundaries due to secondary precipitations of the carbide phase. As a result of this process, plastic deformation is localized in the weakened volume of the body of grain surrounded by strong boundaries. The structure evolution during prolonged heat aging has the greatest effect on impact strength. At the same time, the change in ultimate and yield stress is insignificant. The main contribution to the change in mechanical characteristics of steel is made by the secondary precipitates of the carbide phase.

The influence of long-term operation at 515°C on structure and properties of steel grade 09Cr18Ni9 was investigated. Structure and phase composition were obtained using optical and scanning electron microscopy. The phase composition of the steel in equilibrium state was determined by thermodynamic modeling in the software package FactSage.
As a result of the study, it was found that during the operation at 515°C with a duration of 195 000 h, the structure changes occurred in the steel grade 09Cr18Ni9 with the formation of secondary phases, initiated by the release of elements with limited solubility from the supersaturated solid solution. The presence of the following secondary precipitates in structure of a solid solution of austenite: Cr23C6 chromium carbide, ferrite (α), G-phase.
Based on a comparison of the thermodynamic modeling results and the experimental determination of the phase composition, it was established that the structure of the steel is in a state close to equilibrium.
The mechanism of the course of structural transformations, the sequence of formation of secondary phases was revealed and described. At the initial stage, chromium carbide is formed, then α-ferrite is formed near the carbides, and then G-phase is formed.
The results of the tests for impact strength and static elongation showed that the change in phase composition in process of thermal aging leads to embrittlement of the steel - a reduction in ductility and impact energy.
Fractografic studies of fracture surfaces of samples showed that the decrease in plasticity during long-term high-temperature operation is associated with softening of the grain body and strengthening of the boundaries due to secondary precipitations of the carbide phase. As a result of this process, plastic deformation is localized in the weakened volume of the body of grain surrounded by strong boundaries.
The greatest influence of the evolution of the structure with prolonged thermal aging on impact strength. At the same time, the change in ultimate and yield stress is insignificant. The main contribution to the change in mechanical characteristics of steel is made by the secondary precipitates of the carbide phase.

Ecological and economic aspects of vinyl chloride production are considered as the main resource for production of polyvinyl chloride using by-products of coking enterprise, including low-grade coke, as well as coke gas. Implementation of this project is possible based on carbon technologies and technology of conversion of methane contained in coke gas into acetylene using hydrogen-arc pyrolysis. It is proposed to include cryogenic separation of coke gas into methane and hydrogen, needed for implementation of this technology and production of hydrogen chloride as a component for production of vinyl chloride in process of raw material preparation. Rational use of resources of two Kemerovo enterprises - “Cock” PJSC and “Khimprom” PJSC for this product manufacturing allows optimization of added value chain. Currently, “Coke” PJSC has inoperative volumes of coke gas, which can be used as a raw material for vinyl chloride production. Carbon technology of PVC production, as international practice has shown, is economically advantageous if cost of coal raw materials and waste coke production is 40% lower than cost of oil or natural gas. Analysis of economic expenditures and cost of vinyl chloride production based on added value chains have identified the most “narrow” elements of technological process, requiring innovative solutions to reduce costs and environmental impact of production.

In computer simulation of heat and mass transfer at metals ladle degassing (with a sufficiently high melting point) from the dissolved nitrogen in electrostatic field of subcritical tensions, there is a problem of statement of a boundary condition to the equation of convective diffusion on border “vacuum - metal”. The purpose of computer simulation was the technology optimization. Classical form of the Siverts law doesn’t consider the external impact on fusion. The authors offer the generalizing record of this law which includes tension of the electrostatic field and extent of atoms ionization of nitrogen dissolved in metal in upper layer of this border. Its correctness is confirmed by three-criteria check.