The paper presents the results of studies on the influence of mechanical characteristics of harp screen material on the technological  parameters of screening. A mathematical model of the vibrational  process of harp screens is presented depending on the length of their  free areas, magnitude of technological load and characteristics of the screened material. Dependences of the relative vibrations amplitudes  of rubber and cable strips on the length of their free areas are determined for different values of process load. As a result of the researches, it was established that the amplitude of the relative vibration of  rubber strip under load decreases with increasing length of their free  areas and for steel cable strips it increases, reaching a maximum at  certain values of process load. It was also found that presence of the  load dramatically reduces the amplitude of relative vibration of rubber  strips, especially, in the area of dimensionless frequencies of the order of (0.6  –  1.4)g, while the vibrations amplitude of cable strips vary  slightly in this frequency range. The article presents information on  rubber-cable harp screening surfaces of mesh type: strips in the form  of steel cables, rubberized with rubber cover having lateral separation  projections. The use of rubber-cable strips as working elements of the  screening surface allows to increase the “open area” of the screen due  to the increase of distance between supports while maintaining high  and stable amplitude of strips vibrations. Optimization of mechanical characteristics of the working elements material of harp screens and  conditions of their fixation allows to intensify separation of screened  material into fractions by eliminating sticking of the screened surface  with clay particles and clogging of the material with “difficult” grains, and to improve significantly technical and economic indicators of the  screening process. Such screening surface passed successful industrial tests at a number of quarries producing construction aggregates for the separation of crushed stone and gravel. Economic efficiency of the rubber-cable harp screens is presented in comparison with the wire screens in technological schemes of processing of mineral raw materials.

The problem of determining the maximum diameter of working rolls is typical for screw rolling mills that have more than two working rolls. Precise determination of the working roll diameter is especially important for three-roll mills, which are widely used in such industries as rolling and calibration, and radial-shear rolling mills operating at large feeding and rolling angles. Typically, the diameter of working rolls is determined in a constructive way or using 3D modeling. These methods are quite complex, require special skills, and do not allow investigation of the influence of main tuning mill factors such as feeding and rolling angles. There is a calculated method for determining the diameter of the roll barrel for a three-roll mill, but it is applicable for mills working at feeding angles of up to 10 degrees and rolling angles of 4  –  7  degrees. In conditions of radial-shear rolling, this method is not used, since it does not take into account the influence of feeding and rolling angles on which the conditions of the deformation process, manufacturability and quality of the products depend. The article considers a more general method for determining the diameter of working rolls of three or more rolling mills, taking into account their rotation at the feeding and rolling angles. The relationship between diameter of the rolls, their number, minimum diameter of the deformation center, the feeding and rolling angles are shown, which makes it possible to evaluate the structural capabilities of both three and four-roll rolling mills. The results of the presented work make it possible to expand the possibilities for further studies of the technology and equipment of three-roll screw rolling mills for the production of solid and hollow products using completely new deformation modes for the processes of rolling out hollow products of their reduction as well as radial shearing rolling. Importantly, it is possible to supplement existing knowledge about the change in geometry of deformation center, and also to predict geometric parameters of the working rolls of the projected multi-roll mills for given rolled products sizes.

The role of manganese in the production of steel is exceptionally high. A feature of the silicothermic process of obtaining refined ferromanganese is the large loss of manganese with waste slag. When waste slag is cooled, it crumbles to form a fine dust due to the polymorphic transformation of calcium orthosilicate β-Ca₂SiO₄  →  γ-Ca₂SiO₄ at temperature of 450  –  470  °С with an increase in volume by 12.3  %. As the volume increases, considerable internal stresses appear inside the slag, which leads to dispersion of the slags into finely dispersed state during their cooling. This work is devoted to improving the technology of smelting refined ferromanganese grades, using special complex reducing agents. Experiments have been carried out to simulate the smelting process of refined ferromanganese in an ore-thermal refining furnace RCO-0.1 MVA using aluminosilicomanganese (ASM). The technological modes of the smelting process are established, i.e. optimal composition of charge. Charge went evenly without collapses and emissions. The stability of the current load was observed. Thus, the principal possibility of obtaining a refined ferromanganese with the use of a complex ASM alloy as a reducing agent was proved by the largelaboratory experimental melting. The use of ASM as a reducing agent, instead of ferrosilicomanganese, is due to the sufficient content of silicon and aluminum in it. The presence of chemical compounds and solid solutions of iron, silicon and aluminum in ASM should significantly reduce losses of silicon and aluminum for oxidation processes when interacting with air oxygen. And involving ASM alloy in the metallurgical redistribution, in refined ferromanganese smelting, instead of expensive ferrosilicomanganese will make it possible to obtain an alloy with high added value and with the best technological parameters, due to the presence of additional aluminum in it. The results of X-ray phase studies of slag samples show that the mineralogical components are gehlenite, dicalcium silicate and manganosite. It is noted that gelenite in them is the dominant phase, which is a solid solution, preventing the dispersion of slag. As a result of the theoretical and experimental studies, the tasks have been solved - the smelting technology of refined ferromanganese was developed and tested using a special complex reducing agent – ASM.

The article presents theoretical and technological foundations for the production of complex alumosilicomanganese alloy (ASM) from high-silicon manganese ore, Karaganda high-ash coals and Teniz-Korzhunkol coal basins (Borly and Saryadyr coal deposits), Tekturmas deposit quartzite and long-flame coal of Shubarkol field. Based on the reference data and calculated thermodynamic data (for compounds with unknown thermodynamic data), a mathematical model of the phase structure was constructed by conducting a thermodynamic-diagram analysis of four-component Fe – Si – Al – Mn system. The compositions of alumosilicomanganese obtained from the coals of Karaganda and Teniz-Korzhunkol coal basins, in contrast to ASM alloy from Ekibastuz coals, are shifted in the region of tetrahedra with relatively large volumes. This fact indicates their increased stability and technological predictability. The results of the series of experimental tests carried out in an ore-thermal furnace has shown the possibility of obtaining an ASM alloy with controlled chemical composition using high-ash coals of Borly and Saryadyr fields, the substandard high-silica manganese ore of Zapadny Kamys field, addition of long-flame coal from Shubarkol deposit and quartzite of Tekturmas deposit to the mix by continuous slag-free process. Chemical composition of the alloy was regulated by addition of manganese ore to the sample of charge materials. A  complex alloy was obtained with the following chemical composition (%  by mass): 32  –  53  % of Si; 15.5  –  25.0  % of Al; 12  –  32  % of Mn; 8  –  20  % of Fe; 0.02  –  0.05  % of P; 0.2  –  0.5  % of C. The resulting metal does not crumble into powder when stored. This is ensured by low phosphorus content and high aluminum content of more than 10  %. Phase components of the experimental alloy were determined. The use of dumping high-ash coals, substandard manganese ores and the complete elimination of coke use ensure a low cost of the alloy. It is proposed to use this alloy for deoxidation and alloying of steel, and also as a reducing agent in the production of refined ferromanganese grades.

The article presents results of large-scale laboratory studies on the basis of Chemical-Metallurgical Institute named after Zh. Abishev on establishing the possibility of using a mono-charge for smelting standard carbon ferrochromium. Enlarged-laboratory studies were carried out in an ore-thermal furnace with transformer capacity of 200 kVA. Duration of the pilot campaign was 4 days. Three variants of briquettes containing various reducing agents were tested, including: traditional charge (coke PRC + special coke + Borolinsky coal); briquettes with coal from Shubarkol; briquettes with Borlinsky coal; briquettes with coke of China. As a comparative variant, traditional technology with charge materials without briquetting was used. In total, when conducted large-scale laboratory studies it was 41 smeltings. The tests began with a comparative version, which was chosen as technology closest to the technology at Aktobe ferroalloy plant. On the traditional charge, top worked without the uniformly gassing over entire surface of the top. Recovery rate of chromium in the alloy was 79.3  %. Change to briquettes with Shubarkol coal in general has led to the process intensification with more stable current load. The furnace productivity increased to 165.9 kg Cr/day due to increase in the contact surface of reacting phases in briquettes. When using briquettes with Borlinsky coal, satisfactory technological parameters of the smelting process for high-carbon ferrochrome were also obtained, extraction rate of chromium into the metal was 84.91  %. When using briquettes from 0  –  10  mm ore fraction ore and CPR coke in the charge, furnace operation and state of the top were not different from previous periods. The charge also went off evenly, without collapses, the briquettes on the top were not destroyed and current load was highly stable. The work also presents comparative technical and economic indicators for all technologies using mono-charge briquettes.

Oolitic brown clay iron ores are of prime economic importance because of their enormous stocks in the world. However, their use in metallurgical production is very severely limited at the present time because of the high content of phosphorus in them. The process of phosphorus extracting from these ores almost cannot be realized by the known enrichment methods, since phosphorus presents in oolites in the emulsionated and impregnated state, without forming the independent minerals in this case. Therefore, using of ores of the given type is very limited. Growth of the world steel production at this time has considerably increased demand for iron ore, for that reason in the last decades in the world there were made considerable efforts on creation of new manufacturing schemes of brown clay iron ores obtaining standard iron ore concentrates. Considerable reduction of rich and easily beneficiated iron ores in Kazakhstan results in necessity to attract in metallurgical production the huge resources of the easily extracted ooli tic brown clay iron ores of Lissakovsk, Ayat, Priaral, and other fields with the iron content from 35 to 40  % and phosphorus up to 1  %. The technology of thermomagnetic beneficiation is represented as the most self-sustainable and acceptable dephosphorizing technology of brown limonites. The essence of the technology consists in the reproduction by liquid hydrocarbon reducer (LHR), mesmerizing roasting of the concentrate, magnetic concentration of the roasted raw material receiving the magnetic concentrate with the subsequent dephosphorizing of the obtained concentrate by the acid leaching method. The technology was tested in pilot conditions by representative samplings of the Lissakovsk concentrate and the ores of Ayat and Kokbulak fields.

Scientists of the Chemical-Metallurgical Institute named after Zh.  Abishev develop new types of highly effective alloys based on resource-saving technologies that allow the complex processing of natural and technogenic raw materials, such as carbonaceous waste, chrome ore fines, etc. Therefore, it has led to the creation of a onestage, slag-free and non-waste technology with the maximum use of all useful charge components. With disappearance of rich ore reserves, as well as the expansion of demand for raw materials and the development of technology, the rich ores are replaced by poorer and substandard ones that require new methods of processing. The maximum use of raw materials and industrial waste, if this is economically justified, is one of the basic requirements for the technology. This task is closely intertwined, and in many cases coincides with another task – the development of integrated methods of raw materials processing, which, in the general production cycle, allows using, if possible, all useful elements of raw materials. The main objective of the study is to find ways to improve the use of sub-standard chrome ore. As a reducing agent in the electrothermal smelting of the ACS alloy, instead of expensive coke, without which no process of carbothermic smelting is required, a cheap high-ash Borly coal was used. The coal ash, which mainly consists of silica and alumina, is an additional source of silicon and aluminum in the alloy. This technology will be simple and allows regarding substandard chromium ore as a complex metallurgical raw material, since not only chrome is used, but also the components of the waste rock – silicon and aluminum. As a result of the complete reduction of all charge oxides, this technology will make it possible to obtain a complex alloy of ACS with an approximate chemical composition: 39  –  43  % of chromium, 23  –  27  % of silicon, 7  –  10  % of aluminum. The transition of the main components of the charge to the alloy will be: 82  –  85  % of chromium, 68  –  70  % of silicon, 59  –  60  % of aluminum. In this paper, the results of experimental studies on the production of a complex alloy of ACS (aluminum-chromium-silicon) from high-ash coals of the Borly deposit and chrome ore minerals of the Donskoi GOK are presented. The course of furnace operation is described with a lack, excess, and also the calculated amount of the reducing agent. The ways of eliminating the upset in furnace operation are shown.

Nowadays there are different points of view about the cause of global climate change. The current warming, according to one version, is related to the greenhouse effect, i.e. with increasing concentrations of greenhouse gases (mainly carbon dioxide, CO₂ ) in the atmosphere. It is believed that the uncontrolled growth of greenhouse gases in the atmosphere may lead to negative consequences. The position of  UNFCCC and IPCC proposing accounting of greenhouse gases is of recommendatory nature. In particular, an inventory of greenhouse gases can be produced, taking into account the particularities of national development. The main objective of the greenhouse gas inventory is defining reserves to reduce them. Main anthropogenic sources of CO₂ formation in the Russian Federation are reviewed. Comparative indicators of CO₂ emissions in different sectors of production are provided. The methodology for greenhouse gases in Russia is considered, in particular with respect to the steel industry. The analysis has shown that official methods to assess CO₂ emissions into the atmosphere are mainly Base and Sectoral approaches and Level 2 method. Detailed approach and Level 3 method are used for a limited number of metallurgical processing. Part of the CO₂ emissions from ferrous metallurgy, in particular the emissions from the production of blast furnace coke, is accounted in the energy sector. According to the inventory estimation, total anthropogenic CO₂ emissions on the territory of RF have decreased and amounted in 2015 75  % from the level of 1990: compared to 1990, the CO₂ emissions of the steel industry also decreased. Estimated share of the ferrous metallurgy in anthropogenic emissions of CO₂ compared to 1990 (4.0  %) has increased and amounted to 4.8  % in 2015.

The thermodynamic modeling method, which is based on calculation of the equilibrium in «oxide melt-metal-gas» system, is intended to describe the bubbling reduction of metals from a multicomponent oxide melt by reducing gas. Originality of the technique is that the equilibrium was determined for each unit dose of gas introduced into the working body, with contents of the metals oxides being reduced in each subsequent design cycle equal to equilibrium in the previous one. This approach allows modeling processes and qualitatively assessment of the completeness of reactions in pyrometallurgical aggregates using blowing the melt with reducing gas. The initial oxide system NiO  (1.8  %)  – FeO  (17.4)  – CaO  (13.5)  – MgO  (1.9)  – SiO2  (58.0)  – Al₂O₃  (7.4  %) by content of the components close corresponded to the composition of oxidized nickel ore. The ratio of CO₂ /CO in the gas mixture varied between 0 and 0.33. Depending on the amount and composition of the gas introduced into the working body, content of nickel and iron oxides in the melt (1823  K) was evaluated, the amount and composition of the formed metal (ferronickel) was determined, as well as the parameters (ratio of slag and metal, reduction degree of metals) that are important in the process implementation in industrial conditions. Increase in the consumption of pure carbon monoxide monotonously reduces the content of nickel oxide in the melt, while the content of iron oxide at the beginning increases, and then decreases. With the introduction of CO in the amount of about 100  m³ per ton of the melt, the content of nickel oxide in it is reduced to 0.05  %, and of iron oxide  – to 17  %. The resulting ferronickel contains 70  %  Ni, the ratio of slag and metal is 41  units. A further increase in CO consumption leads to preferential iron reduction. Increase in the CO₂ /CO ratio worsens the recovery of metals from the melt: the degree of reduction of nickel and iron decreases, Ni content in the alloy increases and the ratio of slag and metal increases. At CO₂ /CO equal to 0.33 corresponding to 25  % CO₂ in the gas mixture the reduction process stops. On the basis of the data obtained, it is proposed to process oxidized nickel ore in two stages, the first of which is melt bubbling by gas (preferably, pure CO) to the degree of nickel reduction of 80  –  85  % and to separate ferronickel with 70  %  Ni. Further reduction of metals from the oxide melt (second stage) can be carried out by known carbothermic methods.

Technological processes are multifactorial. The choice of the most significant of them for the correct analysis of the object of research is an important task. For such a ranking of factors, researchers usually rely on their own experience or the opinions of specialists in this field, assessing their consistency in terms of mathematical criteria. However, when developing a new process, this approach can not be used. In this case, experimental methods of selecting factors are preferable. But the cost, duration, and sometimes impossibility of using this method is obvious. In this paper we use a different approach. It was considered that thermodynamic modeling is an experiment, but only numerical. Therefore, you can apply it to the method of mathematical design of the experiment, allowing for one calculation to take into account the effect on the objective function of more than a dozen factors. The partial dependencies of the process indices obtained in this case make it possible, without setting up physical experiments, to weed out insignificant factors and leave strong ones, estimating them by the methods of mathematical statistics. Another important advantage of its application is the ability to evaluate the dynamics of changes in phase and elementary products of smelting, process feasibility according to convection and temperature conditions with the control of and mathematical criterion of the acquired data. The method also allows the process to be controlled by all the factors involved, which cannot be met in everyday modeling. For demonstration, this approach was applied during the development of the ferroborone production technology by carbothermic method using local raw materials. Thermodynamic modeling was performed using pre-selected factors. They were also used in physical simulation of the process in a high-temperature furnace. The experiment confirmed significance of the factors, which were chosen theoretically. The use of the planning method also reduced the number of numerical experiments in 25, and physical – in 125 times for predefined data.Using this approach, the authors have made it possible to compare the obtained data with the results of physical experiment to develop measures to approximate practical results to equilibrium ones with the use of strongly acting factor.

The equilibrium nature of viscosity and fluidity is discovered on the basis of the Boltzmann distribution within the framework of the concept of randomized particles as a result of the virtual presence of crystal-mobile, liquid-mobile and vapor-mobile particles. It allows one to consider the viscosity and fluidity of solutions, in particular, melts of metal alloys, from the point of view of the equilibrium partial contributions of each component in the total viscosity and fluidity, despite the kinetic interpretation of natural expressions for these properties of the liquid. A linearly additive partial expression of viscosity is possible only for perfect solutions, in this case, for alloys with unrestricted mutual solubility of the components. Alloys with eutectics, chemical compounds and other features of the state diagram are characterized by viscosity dependencies that repeat the shape of liquidus curve over entire range of the alloy composition at different temperatures, with an increase in smoothness and convergence of these curves at increasing temperature. It was established that these features of viscosity temperature dependence are completely revealed within the framework of the concept of randomized particles and the virtual cluster model of viscosity in calculating the fraction of clusters determining the viscosity of the alloy. That viscosity of the alloy is found by the formula in which thermal energy RT_cr at liquidus temperature is the thermal barrier of chaotization, characterizing the crystallization temperature of the melt T_cr, as well as the melting point of pure substances. On this basis, a method is proposed for calculating the alloys viscosity by phase diagrams using the temperature dependences of pure components viscosity to change the alloy’s viscosity in proportion to ratio of the clusters fractions at any temperature above liquidus line and for the pure component, taking into account the mole fraction of each component. As a result, a three-factor model of the liquid alloy viscosity has been obtained in which the thermal barrier of chaotization RTcr is used as variable for the first time. It determines the fraction of clusters for both pure substances (at RT_cr  =  RT_m ) and for alloys. This thermal barrier reflects the essence of the virtual cluster theory of liquid and adequacy of the concept of randomized particles.