The data on the complex processing of iron ore from one of the deposits of the Republic of Kazakhstan, which involves several operations of wet magnetic separation with re-grinding of raw products and their subsequent refining to produce a conditioned iron concentrate with 65–66 % iron containing 79–80 % Fe and 2.2–2.5 % Si, are presented. It was found that during the magnetic enrichment of the ore under study, the copper minerals concentrate in the magnetic separation tailings and the copper content in them increases from 0.093 to 0.2 %. A scheme and reagent system have been developed for the recovery of conditioned copper concentrate from magnetically enriched tailings. To obtain copper concentrate, magnetic separation tailings are subjected to regrinding in a lime medium to a fineness of 75 % of the –0.071 mm grade. After two operations of the main copper flotation with the use of water glass, butyl xanthate and frother MIBK, waste tailings are obtained. The froth product of the first basal flotation is cleaned twice. The result is a copper concentrate containing 15.2 % copper, 26.5 % iron, 17.5 % sulfur, 3.47 % silicon, 1.4 % aluminum and 8.5 % zinc, which corresponds to the KM-7 grade according to GOST R 52998-2008. Waste tailings contain: copper 0.08 %, iron 20.1 %, sulfur 0.25 %, silicon 16.2 %, aluminum 6.4 % and zinc 0.045 %. The influence of xanthates with different length and structure of hydrocarbon radical as well as hostaflots and amyl aeroflots on the process of copper flotation is studied. The high efficiency of butyl xanthate in the flotation of copper minerals has been confirmed.

When processing sulfide copper-zinc concentrates at copper smelters, sulfide-arsenic cakes are formed, which are subject to disposal. To solve the global environmental problem of arsenic in the metallurgical and mining industries, it must be reliably concentrated and fixed in technological flows with subsequent waste disposal. The fusion of arsenic cake with elemental sulfur leads to the formation of vitreous sulfides, which are less toxic in comparison with dispersed powdered cake, homogeneous and compact in shape. The fusion product is represented by non-stoichiometric arsenic sulfide, similar in composition to As2S5. The high chemical stability of glassy arsenic sulfides is confirmed by the results of leaching by TCLP method. The fusion products have 100 times lower solubility compared to the initial cake. Achieving the solubility of arsenic in the alloy below the threshold concentration (5 mg/dm3 ) makes it possible to recommend the disposal of arsenic cake by fusing it with elemental sulfur. The fusion products belong to non-hazardous waste and are suitable for long-term storage. The composition and structure of cake fusions with iron powder have been studied. New compounds of variable composition were identified in the fused samples: arsenides and sulfides of iron, arsenic sulfides and arsenopyrites. Studies have shown that the products of fusion with iron have a solubility 10–15 times lower than the arsenic compounds in the initial cake but above the threshold concentration as per TCLP method. Therefore, fusion with iron cannot be recommended for practical use for the disposal of arsenic cakes.

Hydro-gas regularities of liquid combined blowing by gas were studied using cold modeling method at Archimedes criterion for lateral Arl = 12÷120 and bottom blowing Arb = 5÷60 simulating Pobeda bubbling unit. The blowing was performed simultaneously by bottom lance vertically fixed in centre of reactor and by the lateral lance which was attached at an angle 5° to the horizontal axis. The quantitative estimation of instantaneous and average circulation velocities (Vav) of liquid flow elements in different bath areas, depending on the location of blowing zone and Archimedes criterion, was performed. The liquid motion trajectory was determined. A vortex zone was revealed near the liquid surface and the reactor shell, where instantaneous velocity of the liquid flow elements changes from 69.9 to 181.1 mm/s and Vav = 123.8 mm/s. The circulation flows fade in the bulk of liquid and Vav decreases from 123.8 to 47.0 and 54.1 mm/s. It was shown that, in general, circulation velocity depends on the blowing intensity and appears to be higher for the zone of overlapping of lateral and bottom streams. The dynamic blowing conditions, which ensure the direct contact of lateral and bottom jets leading to their interflow and increased spatter formation, were identified. The characteristics of 3 types of surface oscillations for interface phases “pure liquid- gas-liquid layer”, as well as the estimation of the lateral and bottom blowing impact on the type of oscillation were provided. It has been noted that the introduction of the bottom blowing (Arb = 5) causes the wave-like motion of liquid (the 2nd type) along with the transverse oscillations of the 1st type, and at higher values of Arb = 25 the angular oscillations of the 3rd type develop. It has been shown that the presence of a lateral jet at the combined blowing decreases angles of bath swinging to 8–12° to horizontal axis. For the estimation of oscillation intensity, Δhl = (hl )max – (hl )min value, which means the difference between maximum (hl )max and minimum (hl )min height of liquid for the full-wave oscillations (τ), was introduced. The height of liquid (hl ) was plotted as a function of τ, Arl , Arb, Δhl was determined on the basis of obtained graph values, which varied upon modeling over the range of 7.7–69.5 mm. The relation between the liquid circulation velocity and the oscillation value (Δhl ) was established for different bath zones and dynamic conditions of the blowing. The impact of all oscillations types on potential erosive lining wear of Pobeda bubbling unit and the completeness of adoption of charging material nearby the bath surface was investigated.

Magnesium alloys are usually considered as structural materials when the weight reduction is important - in aircraft and space industry for example. In recent years, there has been an increase in the use of new generation ignition-proof high-strength magnesium alloys in the design of aircraft parts. The properties of new ignition-proof casting magnesium alloys ML-OPB (Mg–6.7Y–2.6Zn–0.5Zr–0.35Ce– 0.35Yb; wt.%) and EWZ43 (Mg–3.8Y–4.4Nd–0.6Zr–0.6Zn; wt.%) were investigated and compared with properties of commercial magnesium alloys. The microstructure of investigated alloys in the as-cast condition comprises of a magnesium solid solution and a significant amount of eutectic. Heat treatment according to the T6 mode results in change in the eutectic phase’s morphology and also to their partial dissolution in the magnesium matrix. Long-term high-temperature holding, simulating operating conditions (500 h at 300 °C), leads to the formation of precipitates along the grain boundaries in both alloys, significantly reducing the mechanical properties. During the oxidation of the samples, it was established that the main components that involved into the oxide film and provides the protective properties of the alloys is Y, Nd and Yb. The investigated alloys have a high strength, which is not lower than that of the ML10 alloy. At the same time, the advantage of the ML-OPB alloy is a high elongation at fracture, while the EWZ43 alloy is characterized by high strength. The corrosion rate of the investigated alloys exceeds the corrosion rate of known commercial ML10 and AZ91 alloys, which implies the need for additional protection against corrosion of investigated alloys. At the same time, the castability of ML-OPB and EWZ43 alloys is no lower than that of most commercial magnesium alloys. An oxide film with high Y content and high protective properties is formed when the alloys interact with the sand mold bonded with furan resin. The ignition temperature of the investigated alloys is 100–150 °C higher than that of the ML10 alloy. The flammability test of alloys in the flame of a gas burner, made on cone samples and typical aircraft castings «bracket», showed that ML-OPB and EWZ43 alloys are almost non-flammable under the conditions of experiment.

The issue is devoted to the study of the influence of hafnium on the structure and properties of alloy 1570. Ingots from alloy 1570 were cast into the steel coquille, including those with additives of hafnium 0.1, 0.2 and 0.5 %. To determine the size of the grain structure in the obtained ingots, an Axionovert-40 MAT optical microscope was used, chemical analysis of intermetallic particles was carried out using JEOL 6390A SEM. In addition, for the alloy 1570 and 1570–0.5Hf, the presence of nanoparticles with the L12 structure was studied using transmission electron microscope JEM-2100. Studies showed that hafnium additives make it possible to achieve a significant modification of the cast structure. For example, when introducing hafnium into the initial alloy in an amount of 0.5 % of the total weight, it was possible to achieve a reduction in the average grain size by 2 times. Scanning microscopy data showed that hafnium partially dissolves in particles containing scandium and zirconium as well. The addition of hafnium increases the number of large particles formed during crystallization. Transmission microscopy showed the presence of coherent aluminum matrix nanoparticles in alloy 1570 and having a superstructure of L12, which were most likely formed during intermittent decay during ingot cooling. When 0.5 % Hf was added, no nanoparticles with the L12 superstructure were detected. To explain the latter fact, it is necessary to study the surface of the liquidus of the Al–Hf–Sc system, as well as to study the effect of hafnium on the diffusion coefficient of scandium in aluminum.

The results of the study of targeted sputtering and deposition of ultrafine vanadium and cadmium particles on substrates that are not heated and shifted with respect to the substrate plasma currents are revealed. As a result of the conducted studies, coatings were obtained in the range with a concentration of cadmium from 9.6 to 88.6 at.%. The critical size of vanadium particles capable of forming alloys with cadmium is 0.6 nm. The concentration limit for the presence of solid solutions of cadmium in vanadium is the cadmium content of ~37 at.%, at a higher cadmium content the film coating is represented by a mixture of cadmium phases and a solid solution of cadmium in vanadium. The dependence of the lattice parameter of α-vanadium on the content of cadmium in it corresponds to the expression: а [nm] = 8·10–4СCd + 0.3707, where СCd is the concentration of cadmium, at.%. On the surface of the sample in the region of solid solutions (31.6 at.% Cd), the presence of threadlike crystals of cadmium was found, the reason for the appearance of which is the lattice pressure of the matrix metal. Annealing of films rich in cadmium (69.5 at.%) in vacuum is accompanied by cracking of the coating and the formation of pores. The latter can be used as a method for obtaining porous vanadium.

In this work, the interdiffusion features in multicomponent (high-entropy) alloys of refractory metals were studied. The following pairs were chosen as the diffusion study objects: titanium–equiatomic alloy (Hf–Nb–Ta–Ti–Zr–Mo) and titanium–tantalum for the sake of comparison. The article covers the issues of sample preparation, microstructure study, sample preparation methodology for diffusion research, and experimental results. Diffusion annealing was carried out for 12 h in a vacuum at a residual argon pressure of 6.65·10–3 Pa and a temperature of 1200 °С. Particular attention was paid to the method of combining diffusion pairs (titanium with tantalum, titanium with alloy) by thermal cycling near the polymorphic transformation temperature in titanium (882 °C) within ± 50 °C. The behaviour of the most characteristic elements (Ta, Zr, Ti) in the weld area after the titanium and alloy diffusion pair joining was demonstrated. This is the first time that data on the dependence of the intensity of the corresponding spectral line for titanium and elements of a multicomponent alloy on the penetration depth were obtained. A change in the signal intensity for system elements was observed at a depth of 150–200 μm, whereas a sharp drop in the signal intensity was seen to occur at depths of about 50 μm. The effective value of the coefficient of diffusion of elements into titanium averaged over all elements of the alloying system (except for titanium) at a temperature of 1200 °C was calculated. The obtained value was compared to reference data: the self-diffusion coefficient in β-titanium and diffusion coefficients in titanium pairs with alloy doping elements.