The analysis of the current state of production of rare earth metals (REM) in Russia and in the world was made. Information about REM production in different countries of the world and about new foreign projects for REM production and processing is provided. The article presents the balance of production, export and import of raw materials and products with REM, including scandium and yttrium, in Russia. The maximum volume of REM consumption in Russia was calculated taking into account imported products with REM. This data was compared with other countries, including the former USSR. Much attention is paid to the use of REM in metallurgy. Data on the influence of REM on the properties of cast iron and steel are presented. Information is given about the forms of REM used for their use in the Russian ferrous metallurgy. We have studied the structure of REM consumption in ferrous and non-ferrous metallurgy. On the example of two enterprises (one of them specializes in mass production, and the second – on production of special steels), the structure of REM consumption for steel alloying was studied by type and scope of its application. The development peculiarities of REM consumption in Russian ferrous metallurgy were investigated. The volume of consumption was calculated; data on imports of raw materials with REM for metallurgy and the producers of ferroalloys with REM in Russia is given. We have analyzed the spectrum of steel products with REM. A comparison of the consumption of REM in the metallurgy of Russia and foreign countries is presented. The reasons for insufficient consumption of REM in the Russian metallurgy are considered, an assessment is given on the change in production volumes of certain types of steel and cast iron, and recommendations are made on the growth of REM consumption in metallurgy.

There are two major groups of binder: organic and inorganic binder for agglomeration process for reduction, and sintering for steel production. In this work, effect of composite binder on roasting of Mongolian “Tumurtei” iron ore concentrate briquettes in ambient atmosphere was studied, aiming to clarify optimal parameters of roasting behavior with three different MHA binders for direct reduction. Lignite contains organic and inorganic substances, and according to many previous investigations, it can be raw material for extraction of composite binder. Pressed iron concentrate with MHA binder was subjected to oxidation and reduction process in the electrical furnace. The optimum conditions of experiments were as follows. Parameters of briquetting process were carried out according to the no-binder briquetting test 0.75 t·cm^–2 pressure, 5 seconds pressing time, 8 % of moisture content, oxidation at 950 °C under air flow for 10 min, and reduction at 1100 °C under CO atmosphere. As a result, MHA binder extracted from “Baganuur” lignite affected the reduction degree higher than another two binders in this study. Total iron content in reduced iron is attained to 98.33 % with 1 % of MHA extracted from “Baganuur” lignite. Reduction degree can be expressed by loss of oxygen.

The article considers issues related to the efficiency of metal melts’ filtration depending on the size of non-metallic inclusions, parameters of ceramic foam filters and their location options. Studies of influence of the main structural elements on the filtration processes of nickel melts during casting in a vacuum induction installation were carried out on low-temperature physical models. Modeling of melt filtration processes is based on the hydrodynamic similarity of the processes of motion of melt flows and nonmetallic inclusions in casting tanks. A modeling technique has been developed, the scale has been determined and a model installation has been made. Influence of the arrangement of filtration and dividing walls on the dynamics of metal flows, non-metallic inclusions and filtration efficiency is considered. The efficiency of nickel melts filtration is described depending on the technical parameters both on the filter itself (effective filtration surface, filter thickness, channel dimensions, number of channels per unit area), as well as on the type and size of non-metallic inclusions, design features of the casting device and filter layouts. It was found that the overall filtration efficiency is influenced by the rate and uniformity of the melt flows’ distribution in front of the filter. To ensure uniform distribution of the melt flow rates, a dividing wall with bypass holes is installed in front of the filter, the location of which and their number was also the subject of research. As a result of the studies, the relationships were established between the filtration efficiency, the size and type of non-metallic inclusions when using vertical and horizontal foam ceramic filters during the casting of nickel melts in an intermediate casting tank of a vacuum induction installation. It was found that with a vertical arrangement of the filter, its efficiency is higher than with a horizontal one. An additional means of increasing efficiency of the filtration system is the use of a dividing wall. The optimal number of holes and the location of the baffle in the casting tank were determined, ensuring a uniform distribution of melt flows along the height in front of the filter and an increase in its operation time.

Currently, the most common fluxing additive to pellets is d mite CaCO₃ ·MgCO₃ , in which the content of magnesium oxide can be from 17 to 22 %. But if it is necessary to increase magnesium oxide in pellets, it is necessary to increase the dosage of dolomite, and thus the iron content decreases, which entails a decrease in yield ratio at subsequent processing. One of the fluxes containing magnesium is brucite. Compared with dolomite, magnesium oxide content in pure brucite is more than 3 times higher. The basis of FLUMAG M flux is brucite. The content of magnesium oxide in it is not less than 55 %. The paper presents series of laboratory studies on the effect of FLUMAG M flux dosage on pelletizing ability of the charge and such properties of iron ore pellets as compressive, impact and abrasion strength. We have made the tests on raw and fired pellets with FLUMAG M flux. The comparative analysis of strength properties of the pellets obtained with the use of FLUMAG M and limestone was performed. Content of the binder – bentonite and magnetite concentrate for all experiments remained unchanged. The results of these experiments indicate that FLUMAG M does not interfere with charge pelletizing ability. The strength of raw pellets for discharge and compression with FLUMAG M flux has small deviations from the pellets with the addition of limestone. Roasted pellets with the addition of FLUMAG M flux have higher strength than ones with limestone. The higher difference in strength properties is observed at the flux content of 2 %.

The article presents theresults of research on the influence of modes of the volume electric arc surfacing on the geometric accuracy of objects of the “cube” type made of 09G2S and 06Kh19N9T steel fillers. It was found, that when surfacing thesamples made of 09G2S steel, the actual dimensions in length and width, generally exceed, and in height are smallerthan the specified dimensions of the model. Itmay be due to melt spreading on the substrate during formation of the first layers. The optimal surfacing mode for objects of the “cube” type made of 09G2S steel was defined. When surfacing the samples of 06Kh19N9T steel, spreading does not occur, but all the actual dimensions are smaller in relation to the specified. Itmight bedue to the influence of shrinkage processes occurring in the surfaced layers during their solidification. The most optimal mode for the samples made of 06Kh19N9T steel is the mode in which the size reduction in length and width was no more than 2.5 %, and in height – 13.5 %. Studies on the influence of welding arc voltage and the grade of filler material on width of the surfaced track confirmed the tendency of 09G2S steel to spread over the substrate in the entire studied voltage range (11 – 19 V). The structure of the surfacedsamples was investigated. Mechanical tests on the tensile strength of the surfaced samples at room temperature have shown that they have an acceptable set of mechanical properties that exceed the reference values.

The problem of reducing emissions of sulfur dioxide from the flue gases of coal-fired TPPs is highly relevant for domestic energy in connection with the annual increase in coal production. This article analyzes statistical data in the field of coal mining, describes the current state in the field of gas purification and ash collection in the mining and metallurgical industry of the Russian Federation. To regulate pollutant emissions by stationary sources in Russia, a system of maximum permissible and temporarily agreed emissions (MPE and ENV) was introduced. The country takes part in international programs aimed at protecting the environment from the harmful effects of human activity. Despite the general dynamics of reducing air pollution in the Russian Federation, emissions from mining and metallurgical enterprises only increase. This is due to deficiencies in the technical condition and operation of dust and gas cleaning equipment at electric power enterprises. The main ones are the moral and physical deterioration of the equipment fleet, the need for reconstruction and modernization of devices. The average degree of flue gas cleaning from ash at Russian TPPs is 95.5 %, which is noticeably less than abroad. Efficiency of the gas treatment plants used does not meet modern environmental requirements. The flue gases at our TPPs are not cleaned from sulfur and nitrogen oxides; there are practically no devices for continuous monitoring of TPP emissions. The article provides the rationale for the transition of enterprises to the best available technologies (BAT) in the field of gas purification. The use of a gas conditioning system allows 30 – 40 % reduction in the amount of funds spent on the construction of electrostatic filters. In recent years, in connection with the advent of new technologies for burning coal, filters for the purification of hot gases made of ceramic materials have been created. We have analyzed the state of gas purification and ash collection in the mining and metallurgical industry of the Russian Federation and its impact on the atmosphere. An assessment of the current state of gas purification equipment at the enterprises was carried out.

To predict the chemical composition of heat-resistant high-chromium steels with ferritic-martensitic structure (HFMS) (with the number of alloying elements up to 10 and the same number of parameters of production and heat treatment technology), a mathematical model is needed. In this work, I searched for the dependences of the yield strength and ultimate strength of HFMS on the content of alloying elements and test temperature without analyzing technological factors due to their uniformity. Analysis of the samples from ten steel grades was carried out on the basis of the experimental data including 63 tensile tests at 20 – 720 °С. Regression multiplicative dependencies are proposed to take into account exponential and power-law form through the corresponding factors: solid solution and dispersion hardening, total temperature softening of the steel, carbon content, total molybdenum and tungsten content, and strengthening effect of manganese. Estimates of the effect of nitrogen and silicon on the predicted strength characteristics have shown that a factor that takes into account the effect of nitrogen improves the model and is necessary in the general formula, and introduction of a factor that takes into account silicon content, worsens the model. Introduction of a silicon factor in the formula may be necessary in analysis of steels with high silicon content (type EP-823). The experimental fact of a close relationship between yield strengths and tensile strengths for the studied HFMS steels made it possible to use for the yield strength the form of equation and forecast for the ultimate strength, which differs only by coefficients in variables. Deviation of the calculated model yield strengths and tensile strengths from experimental is 13 – 18 %. An example of analysis of the yield strength behavior of steels with experimental chemical compositions is given. It is shown that the dependences found for the yield strength and tensile strength are stable with respect to the increase of experimental data matrix: with an increase in the number of experiments from 94 and higher, the coefficient of variation V monotonously decreases up to a maximum array size of 299 experiments.

Influence of the modes of manual electric arc surfacing of coatings with T-590 electrodes on low-alloy steel 09G2S on their structure and hardness was investigated. It is shown that the pulsed arc surfacing of coatings by electrodes forms a fine-dendritic structure of the deposited metal. Microstructure of the heat-affected zone after surfacing consists of several sections: the overheating zone with a widmanstett structure and the normalization zone with a characteristic fine-grained ferrite-perlite structure. In the initial state, the base metal (steel 09G2S) has a hardness of ~2500 MPa. The hardness of the deposited coating material due to strong mixing with the steel metal is ~ 2700 – 3000 MPa, and of thermal impact zone: 2100 – 2300 MPa. When applying the coating on DC mode, heating temperature of the surfacing bath is higher; this, as a consequence, causes grain growth. When coating on pulse modes, a structure with smaller component sizes is formed by directed low-frequency high-energy impact of the electric arc on the formed metal and due to the constant reciprocating motion of the melt with the frequency of current modulation. It was established that the application of the pulse-arc surfacing method allows preserving the previously formed hardening phases in the deposited coatings.

A mathematical description of the material thermal diffusivity a_т in a semi-bounded body is proposed with a relatively simple algorithm for its numerical and analytical by solving the inverse problem of thermal conductivity. To solve the problem, it is necessary to obtain the temperature values of the unbounded plate as a result of a thermophysical experiment. A plate can be conditionally considered as a semi-bounded body as long as the Fourier number Fo ≤ Fo_к (Fo_к ≈ 0.04–0.06). It is assumed that the temperature distribution over cross-section of the heated layer of the plate R is sufficiently described by a power function whose exponent depends linearly on the Fourier number. A simple algebraic expression is obtained for calculating a_т in the time interval ∆τ from the dynamics of temperature change T(R_п , τ) of a plate surface with thickness R_п heated under boundary conditions of the second kind. Temperature of the second surface of the plate T(0, τ) is used only to determine the time of the end of experiment τ_к. The moment of time τ_к, in which the temperature perturbation reaches the adiabatic surface x = 0, can be set by the condition T(R_п , τ_к) – T(0, τ = 0) = 0,1 K. The method of approximate calculation of dynamics of changes in depth of the heated layer R by the values of R_п , τ_к , and τ is proposed. Calculation of a т for the time interval ∆τ is reduced to an iterative solution of a system of three algebraic equations by matching the Fourier number, for example, using a standard Microsoft Excel procedure. Estimation of the accuracy of a т calculation was made by the test (initial) temperature field of the refractory plate with the thickness R_п = 0.05 m, calculated by the finite difference method under the initial condition T(x, τ = 0) = 300 (0 ≤ x ≤ R_п) at radiation-convective heating. The heating time was 260 s. Calculation of a_т, i was performed for 10 time moments τ_{i + 1} = τ_i + Δτ, τ = 26 s. Average mass temperature of the heated layer for the whole time was T = 302 K. The arithmetic-mean absolute deviation of a_т(T = 302 K) from the initial value at the same temperature was 2.8 %. Application of the method will simplify the conduct and processing of experiments to determine the thermal diffusivity of materials.

A variant of quantitative assessment of metals fabricability by pressure is offered according to the standard tests on mechanical properties. The complex parameter is used, defined as geometrical mean of three parameters characterizing plasticity, hardening and energy intensity of alloys deformation. Relations of scientific and engineering characteristics of deformability assessment for the use of scientific researches results in factory practice are determined, being guided on the standard test methods. Examples of the use of received equations are resulted for a number of steels in processes of metal forming. Testing of the proposed method was carried out according to the known data. Estimation of the complex parameters was made in accordance with Harrington desirability scale. The offered technique can be used for an assessment of fabricability of new steels and alloys.