Том 61, № 3-4 (2017)

The reduction in the specific consumption of deoxidizers in a furnace is due to the effective use of the reducing energy of the gas flow. The efficiency of the reduction processes can be increased by optimizing the BF charging parameters. A numerical procedure for BF charging optimization is developed using a mathematical three-factor model based on the performance analysis of blast-furnace smelting. The optimization procedure based on regression and correlation analysis makes it possible to determine the optimal charging parameters: the number of direct feeds, feed weight, stockline. This decreases the degree of direct reduction of iron. The optimal charging parameters allow formulating recommendations on the intensification of the reduction processes and improving the smelting process as a whole.

The data on the energy intensity, carbon dioxide emission, and end-to-end emission (carbon footprint) for the production of vanadium iron in coke-fired blast furnaces with injection of either natural gas or both natural gas and pulverized coal are presented. Energy intensity is represented by end-to-end process fuel number. Mean values, variance, standard deviation, range of variation of process fuel number, emission, and end-to-end emission of carbon dioxide are calculated using published data on the consumption of coke, natural gas, and pulverized coal in a blast furnace. It is shown that the process with injection of pulverized coal has better performance in terms of energy intensity. Carbon footprint is minimum when injecting natural gas only.

The effect of alkaline compounds on blast furnace operation is studied. It is shown that the main mass of alkaline compounds enters a blast furnace with sinter, coke ash, and pellets, and the main part of alkali emerges from a blast furnace with slag. A quantitative effect is established for an increase in the emergence of alkali with slag with a reduction in final slag basicity. The periodic nature of alkali removal with slag is established. It is found that it is necessary no less frequently that once every 4–5 days in each blast furnace to carry out two to three operating shifts with final slag reduced basicity (CaO/SiO₂) (lower by 0.05–0.15 units than prescribed by the production chart). The technology proposed for alkaline compound removal is protected by an RF patent and implemented at the Magnitogorsk Metallurgical Combine since 2012.

The results of modifying the TPA-220 piercing mill are described. The energy and force characteristics of the mill are evaluated. The dependence of the torque on the tube dimensions and feed angles is established. The performance of the mill after modification and introduction of experimental tool designs is estimated.

A technology and equipment for producing cost-effective hollow billets 30 to 60 mm in diameter for mechanicalengineering parts are described. The developed automated line provides high productivity and is relatively light. The line allows making axisymmetric billets with a through or blind hole with a depth/diameter ratio of up to 8.

The effect of molybdenum in an amount of 0.15% on the microstructure and properties of low-alloy pipe steel plate prepared by controlled rolling technology with accelerated cooling is studied. A favorable effect is established for molybdenum on increasing strength properties and sheet hydrogen induced cracking resistance.

The object studied is the contemporary Castex process of continuous casting–extrusion of nonferrous alloys implemented in a Conform unit with a wheel-crystallizer vertical axis of rotation. The aim of research is to establish relationships for planning equipment structural elements providing implementation of a stable process of continuous feeding of molten metal into a crystallizer channel, its solidification and extrusion into a die orifice. The problem is set of revealing and calculating the main process parameters determining observation of conditions for constancy of second-by-second volumes of metal during its movement from a dispenser with melt to emergence of an extruded object from the die orifice. An original technical solution is provided for implementing metal combined casting–extrusion in a Conform unit with a horizontal wheel-crystallizer. Dispenser dimensions are calculated in relation to the level of melt within it and wheelcrystallizer rotation rate providing stable accomplishment of the test process in a laboratory unit. Test results for continuous casting and extrusion of aluminum alloy AD 31 confirm the correctness of calculated data.

The rolling of VT-6 alloy billets with profiled ends in a screw rolling mill is studied to determine the geometry of the end sections minimizing the funnel depth after rolling. The rolling experiment conducted is of 2³ factorial design. The nonstationary stages of the process are simulated using Deform-3D software. The results of the simulation are used to find the shape and dimensions of the end sections of the billet that minimize the funnel depth.

The basic stages in the development of and the recent developments for metallurgy and foundry by the Vulkan-TM Scientific and Production Enterprise (Tula) are considered. The design features of unified VTseries slide gates of new generation are outlined.

Results are provided for calculation of the predicted blast furnace operating regime using converter slag in the iron-ore part of the charge without implementing additional measures with the aim of evaluating its effect on process indices. Introduction into a blast furnace charge of fractionated converter slag may be performed in order to increase slag magnesia content and to use it as a basic for flux for increasing the proportion of pellets in a charge of an individual furnace without changing the prescribed sinter basicity for the whole workshop. An increase is provided in gas permeability of the dry part of a charge for a furnace with a limited upper zone in the case of distortion of its profile. Charging converter slag into a blast furnace gives rise to an increase in iron phosphorus content. Prolonged use of converter slag in all blast furnaces gives rise to accumulation of phosphorus in metal, and consequently to resolution of the problem of removing phosphorous during converter treatment. The choice of the ratio of charge components may be made by maintaining the iron content in a fluxed charge at a level relating to specifications of the technology and the task of providing an economic furnace regime. Solution of the question of the expediency of using converter slag in blast furnaces is possible with comprehensive analysis of the problem: evaluation of the economic expediency of its use as a fluxing additive; economic development of this question for a blast furnace – converter production complex; choice of a furnace operating regime in accordance with its operating conditions; analysis of the ecological problems of the operation of an enterprise and a region.

Results are provided for calculating arc efficiency of steel-smelting arc furnaces in various stages of charge melting with a change in slag layer thickness. Arc efficiency is at a maximum after cutting a well in a charge. Charge thickness decreases during melting and arc efficiency is reduced. An increase in slag layer thickness in the opening period leads to an increase in arc efficiency. Calculated data are confirmed by experimental studies in steel melting arc furnaces.

Results are given for a study of metal deformation state with screw rolling in a three-roll mill by means of computer modeling. Quantitative characteristics are obtained for the unequal distribution of degree of deformation through a workpiece cross section. Features are established for the use of screw line pitch length, partial reduction, and penetration index for the plastic deformation zone to workpiece axis in relation to screw line pitch number. Recommendations are given according to which in calculating roll calibration the roll profi le should be selected so that deformation penetrates the whole workpiece depth over the whole deformation site length.

Results are given for research aimed at improving the quality of large tonnage flat ingots under RUSAL Joint Company (Krasnoyarsk) conditions as a result of reducing the hydrogen content within them to less than 0.1 cm³/100g. For this purpose, under production conditions the change in molten aluminum alloys series 1XXX hydrogen content is analyzed in the main stages from the aluminum electrolyzer to the casting machine. Production operations are determined within which there is significant melt impregnation with hydrogen. Research precision is provided by using a developed procedure for molten sample collection in the main production operations and considering the specific nature of production. Technical solutions are proposed from research results aimed at reducing melt hydrogen expansion.

Comparative tests are performed under laboratory conditions in units modeling existing electrolytic tinning units for contemporary ecologically clean tinning electrolytes based on methanesulfonate (Niveostan 200 version) and sulfamic acids. The main comparison criteria are: adaptability (the range of tolerance for the main parameters); hydrolysis stability and the level of sludge formation; tinned coating qualitative properties. It is shown that both types of electrolytes meet the specifications laid down for tinplate industrial tinning electrolytes and make it possible to prepare high quality anticorrosion coatings over a wide temperature range from 30 to 60°C, and they may provide good electrolytic efficiency (tin current efficiency 95%) with sensible limitation of the current density limit. Sulfamic electrolyte provides a broader range of variation in current density. Methanesulfonate electrolyte without admixture of iron is hardly prone to sludge formation. With an identical iron content (10 g/liter), both electrolytes have about the same low level of tin loss in sludge, but the anticipated rate of iron accumulation is greater in methanesulfonate electrolyte. The main advantage of methanesulfonate tinning is the high electrolyte electrical conductivity making it possible to reduce electrical energy consumption. Maximum use of the technical possibilities of both types of electrolyte is possible in new tinning lines planned and constructed in accordance with features of the production processes used.

Based on the Eh–pH diagram for the Se–H₂O system, a new method is proposed for leaching selenium from copper anode slimes using a nitric acid–sulfuric acid mixture. The effects of solid/liquid ratio, HNO₃ and H₂SO₄ concentrations, leaching temperature, and reaction time on the leaching efficiency of selenium were investigated. Samples were mineralogically characterized by x-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy to study the transformation of selenium-containing phases during the leaching process. The results showed that the optimal conditions comprised a solid/liquid ratio of 0.25 g/ml, HNO₃ concentration of 0.5 M, H₂SO₄ concentration of 2 M, leaching temperature of 363 K, and reaction time of 3 h. A selenium leaching efficiency of 97.79% was obtained under these conditions. Mineralogical characterization indicated that selenium occurred as Cu–Ag selenide in the raw copper anode slimes. This was first converted to elemental selenium and then to selenite ions in solution.