The article provides the analysis of process flows used for sulfide and oxidized copper ore treatment, reagent schemes, process equipment, indicators of flotation concentration at a number of domestic and foreign concentrating mills and plants. Autogenous and semi-autogenous grinding mills are widely used at the ore preparatory processing at the first stage of grinding to eliminate medium and fine crushing stages. An alternative is the use of high pressure grinding rolls that can reduce electricity consumption as compared to autogenous and semi-autogenous grinding. There is an increase in the use of large-volume and high-performance ore-preparation and flotation equipment for maintaining the quality and quantity of the product. In addition to ball mills, fine and ultrafine regrinding mills of various configurations are widely used at the stage of rougher flotation concentrate regrinding. The analysis of flotation reagents used to improve separation process efficiency was conducted with domestic and foreign approaches to flotation reagent selection shown. It is noted that foreign concentrating mills often use a combination of main and additional collectors. The paper provides the data on flotation reagents used in the copper sulfide and oxidized ore concentration, and their consumption. A combined diagram of flotation-hydrometallurgical processing of mixed copper ore from the Udokan deposit is considered. Conclusions are drawn about current trends in the processing of copper ores including the choice of equipment.

Pobeda furnace operation was studied in the Archimedes criteria range from 5 to 60 using the cold modeling method to determine fluid and gas dynamics of bubbling using a side-blowing gas-protected lance. A transparent reactor of the laboratory setup was made on a scale of 1 : 10. Cylindrical lance nozzle diameter was 5 mm, annular space was 1 mm and angle to the horizontal in the reactor working position was 12°. It is shown that air interaction with water at its excessive pressure of 10⁵ N/m² occurs in the form of a pulsating stream in a cyclical pattern with the different maximum torch size amplitude and the time required to achieve it. Dynamic borders of the primary near-nozzle zone were determined depending on the Archimedes criterion value for separate and cooperative gas flow through the lance shell and central channel in the stream straight-line development area (l_min ≤ I ≥ l_max). Dynamic head of torch pulsation at extremum points varies in the range of 6,00 • 10^-5÷8,26 • 10^-4 Pa. Empirical equations for stream length in straight-line and full stream development areas and liquid release height were obtained depending on the Archimedes criterion value. An intermediate layer of ejected liquid was found between circular and cylindrical submerged streams. Cooperative axial gas flow is maintained at identical Archimedes criteria of air supply to the shell and central channel for the values Ar_sh = Ar_c = 25 at a distance of 0.0094—0.0116 m from the nozzle edge. As a result of research conducted it should be assumed that there is no interaction of blast oxygen from the central channel of the double -flow lance with surrounding melt at a distance of 9—11 cm from the Pobeda furnace lining.

In mechanical engineering, the antifriction tin bronzes, and C92900 bronze for instance are used for parts subjected to wear. The permanent mold casting into steel molds are commonly used to produce parts from C92900 bronze. This work investigates the possibility of C92900 bronze rods production by hot extrusion and upcasting methods. It has been discovered the hot extrusion temperature and ram speed, as well as the casting speed for upcasting that promote no defects in rods. It has been shown that hot extrusion leads to severe grain refinement up to 1.7 gm, and when casting upwards, on the contrary, an increase in the grain size occurs in comparison with the permanent mold casting. After hot extrusion and upcasting, the crystals of the Y-Cu₃Sn intermetallic phase are refined in the bronze microstructure. At the same time, large agglomerations of (Pb) particles can be observed in the extruded bronze microstructure, which leads to a decrease in the coefficient of friction. The maximum hardness and tensile strength were obtained for rods produced by hot extrusion at 600 °C, and the highest elongation in rods obtained by the upcasting method. Tribological studies were carried out according to the «shaft — partial insert» scheme in a kerosene medium with a steel counter body showed that hot extrusion leads to a tenfold increase in wear resistance and a threefold decrease in the friction coefficient in comparison with rods obtained by permanent mold casting. At the same time, for the rods obtained by the upcast method, on the contrary, a decrease in wear resistance is observed. In connection with the mentioned results, it is possible to recommend the hot extrusion method for producing C92900 bronze rods in addition with casting technique.

This study was conducted with calculations made in Thermo-Calc software (TCAl4.0 database) to find out the unexplored data on the phase composition, crystallization behavior of Al—Mg—Si—Ce alloys as regards the compositions of two-phase (Al) + Mg₂Si cast aluminum-magnesium alloys. It was shown that (Al), Al₄Ce, Mg₂Si, Al8Mg5 phases may form during crystallization. At 4% Mg and (Si + Ce) concentrations of 1.5 %, a simultaneous increase in Ce and decrease in Si contents from 0.2 % and 1.3 % points promote consistent reactions L + (Al) + Al₄Ce and L + (Al) + Al₄Ce + Mg₂Si. This suggests that the Al₄Ce phase may hinder the growth of Mg₂Si phase eutectic inclusions. Moreover, at 20 °C such a change in concentrations promotes a simultaneous decrease in the contents of Al₄Ce and Al₈Mg₅ phases, along with a decrease in the amount of magnesium silicide. While adding Ce in the Al—4%Ce—0.5%Si alloy, the fraction of Mg₂Si is approximately constant throughout the entire crystallization range (1.34 %), but each 0.1% Ce increases the Ce-bearing intermetallic fraction by 0.17 %, and at 0.7 % Ce the proportions of two phases are equal. When studying the phase composition at representative annealing temperatures of 400 и 550 °C, it was revealed that the (Al) solid solution becomes supersaturated as a result of Al₈Mg₅ phase dissolving. Each 0.1% Ce increases the Mg content in the (Al) solid solution by 0.005 % in the first case and by 0.01 % in the second one. This indicates a potentially positive influence of Ce on matrix strengthening. Based on the results, it was concluded that it is advisable to add Ce in an amount of up to 0.7 %, which slightly reduces the liquidus temperature (to ~636+638 °C), but reduces the non-equilibrium solidus temperature by ~30 °C to 421 °C. At the same time, at a constant Mg₂Si phase formation temperature (581 °C), the eutectic crystallization range (Al)+Al₄Ce expands with Ce addition, which can compensate for the decrease in casting properties. The Al—4%Ce—0.5%Si—0.7% Ce alloy has the following phase composition: Al₄Ce 1.19 %, the [Mg₂Si/Al₄Ce] ratio = 0.89, Al₈Mg₅ fraction is 7.92 % at 20 °C, Mg concentrations in the (Al) solid solution are 3.22 % and 3.36 % at temperatures of 400 °C and 550 °C, respectively. The presented results serve as the basis for subsequent experiments and justify compositions and temperature conditions for obtaining cast aluminum-magnesium alloys with cerium having a modifying effect on Mg₂Si eutectic inclusions.

Process conditions are suggested for manufacturing wrought semi-finished products (2 and 1 mm sheets) from the Al-4.5%Zn-2.5%Mg-2.5%Ca-0.5%Fe-0.2%Zr-0.1%Sc experimental alloy including thermomechanical processing at t = 400450 °С and reduction ratios up to 98 %, as well as softening annealing of the sheet metal at t = 350400 °C for 1—2 hours. It was found that the as-cast structure consists of eutectic phases (Al, Zn)₄Ca, Al₁₀CaFe₂ 5 to 25 gm in size, and a Al₂Mg₅Zn₅ nonequilibrium T-phase located along the boundaries of dendritic cells (Al). Zirconium and scandium form a solid solution with aluminum as a result of solidification. After hot rolling, the structure of 2 mm sheets consists of lineage-oriented discrete intermetallic particles and their conglomerates up to 40 gm in size in the (Al) matrix. The structure of 1 mm sheets features by greater fineness and structure uniformity. The fine structure of deformed semi-finished products was analyzed using transmission electron microscopy (TEM), and this analysis showed that nanoparticles in the Al₃(Zr, Sc) phase of the L1₂ structural type are maximum 20 nm in cross-section. The following level of mechanical properties was achieved in wrought semi-finished products: ultimate strength σ_в ~ 310330 MPa, yield strength σ_0,2 ~ 250280 MPa with relative elongation δ ~ 4.57.0 %. The possibility of TIG welding using standard AMg5 wire as a filler material was studied. It was shown that the new alloy demonstrated no tendency to form hot cracks. According to the results of X-ray tomography, the percentage of porosity in the weld was 1.27 vol.%. The prevalent pore diameter did not exceed 0.2 mm. In general, the resulting structural and qualitative parameters of weld joints contribute to obtaining a strength of 75 % of the strength index of the initial wrought semi-finished products (sheets) achieved by stabilizing annealing at t = 350 °С for 3 hours.

The paper considers the process of creating a permanent connection from the EP693 heat-resistant alloy of the Ni-Cr-W-Co-Mo system used in the manufacture of components and parts of gas turbine engines by welding on the TruLaser Cell 7020 CO₂ complex with pulse-periodic radiation. EP367 filler wire of the Ni—Mo—Cr—Mn system was used to obtain the weld. The influence of heat treatment on the structure and properties of the heat-affected zone and the weld was studied. Based on the research results, the weld structure and kinks obtained by laser welding was studied, weld physical and mechanical properties were identified, the maximum endurance limit for welded joints was determined at 2•10⁶ cycles. The expediency of laser welding of the heat-resistant dispersion-hardening nickel alloy in the manufacture of shells for the turbine support and stator of gas turbine engines was determined. It was found that combined heat treatment (quenching and aging) provides optimal values of strength limits at room and elevated temperatures, as well as short-term strength of welded joints. Based on the strength calculation of the turbine support and stator of gas turbine engines and the obtained experimental data on the strength of welded joints made using laser welding with pulse-periodic radiation, the safety factor was 1.35 to 3.0. This technology is proposed to be introduced into production in the manufacture of parts and assemblies such as shells for the turbine support and stator of gas turbine engines in order to improve the quality of welds by reducing the time of high-temperature heating due to lower heat input.

The paper considers the effect of Ta-Zr binary system splat quenching implemented by the method of pendant drop melt extraction. The study was conducted using two mixtures of tantalum and zirconium elementary powders with a content of 60 and 6 % of tantalum respectively. After mixing, the compositions were pressed at 250 MPa in a steel mold on a hydraulic press. Sintering was carried out in a vacuum furnace at 1350 °C and a pressure of 10^-3 Pa. Splat quenching was carried out in a vacuum at 2•10^-2 Pa using electron-beam heating and a spinning disk absorber. Resulting fiber thickness was 15 to 80 gm. The results of testing splat-quenched Ta—Zr alloy discrete fibers and samples formed as a result of rod stock melting by electron-beam heating (as-cast) were studied and compared. It was found that the structure of splat-quenched fibers of the alloy with a Ta content of 6 wt.% consists of 5—10 gm needle-shaped grains, and the alloy with a Ta content of 60 wt.% has a columnar dendritic structure. A study of tantalum and zirconium distribution across the fiber cross-section showed that cooling rate reduction to less than 10⁵ K/s leads to monotectoid transformation in the alloy with a tantalum content of 60 wt.%. It was found that for an alloy with 6 wt.% Ta the fiber microhardness value is 1.5 times higher in comparison with the same alloy without quenching, and for an alloy with Ta 60 wt.% it is higher by a factor of two.

The article deals with the formation and processing of waste at aluminum production plants. Based on the analysis of literary sources and practical data, the reasons for the formation of metallurgical waste in the territory of the Russian Federation are established. The analysis of research conducted in scientific organizations is presented. It was found that one of the most promising for waste processing is alumina-containing sweepings formed during the production of liquid aluminum in Soderberg cells during various process operations. Alumina-containing sweepings are waste of complex variable composition swept away in electrolysis shops. It was found that alumina-containing sweepings consist of cryolite (Na₃AlF₆), chiolite (Al₃F₁₄Na₅), corundum (Al₂O₃), siderite (FeCo₃), pyrite (FeS₂), quartz (SiO₂), feldspar ((Ca, Na)(Al, Si) AlSi₂O₈), carbonaceous matter and (NaF)•1,5CaF₂•AlF₅ technogenic phase. Their processing is of interest due to the fact that they contain a significant amount of valuable components (Na₃AlF₆, Al₂O₃, AlF₃) that can be extracted and reused in aluminum production to reduce the cost per unit. The problem is that sweepings contain components (SiO₂, Fe₂O₃), which have a negative effect on the electrolysis process when in contact with electrolyte. The data obtained when studying the chemical composition of monofractions made it possible to conclude that the exclusion of the dark (grayish-black mass) with the maximum content of impurities (SiO₂, Fe₂O₃) will substantially solve the stated problem of the study. Based on the hypothesis put forward, the paper presents the results of 0—10 mm and 0—5 mm sweepings air classification in cascade-gravity and centrifugal classifiers. Based on the studies conducted, we recommend using 0—10 mm sweepings air classification in the cascade gravity classifier in the processing flow of alumina-containing sweepings of aluminum production.