The article presents the results of a new magnetic liquid separation method study. This method differs from known methods by the presence of a bilayer separation medium in the form of immiscible ferromagnetic liquids of different density. When separating in a bilayer separation medium, the particle equilibrium condition on a plane surface, recorded according to Young's law and Neumann's rule, must be supplemented by the linear tension of a curved phase interface. A linear tension is a force and energy barrier that prevents fixing of fine particles of noble metals at the phase interface, and is the reason for their effective extraction into the heavy fraction. The magnetic liquid separation method was tested on concentrates containing platinoids. It was established that during separation in a bilayer medium, the extraction of platinoids into the heavy fraction was 25,89 %, and during separation in a water-based ferromagnetic fluid it was 19,73 %. The quality of the heavy fraction makes it possible to direct it to the hydrometallurgical process, bypassing the copper plant, which increases the extraction of precious metals by 5,0 % abs.

An enlarged version of the flotation unit equipped with a high-pressure rotational pulsation aerator (HPRPA) was manufactured. Studies and tests were carried out using a refractory fine-grained gold-containing ore sample from one of Kazakhstan deposits. The experiment and practice of flotation using the HPRPA developed by the authors demonstrated that pressure fluctuations created by the aerator ensured the efficiency of the functional use of two periods: (1) dissolution of additional gases in the high-pressure compression period, which provides the aeration process with the necessary amount of dissolved gases; (2) pseudo-cavitational emission of gases in the medium rarefaction period, which ensures aeration with gas emission from the aqueous phase directly on hydrophobic mineral microparticles, i.e. selective flotation of microdispersions. The obtained results showed that ore flotation in the flotation unit equipped with the HPRPA lead to a very significant positive effect not only with regard to the extraction of metals, but also to the quality of obtained concentrates.

The article studies flotation properties of BTF-1552, IMA-206, and IMA-I413 alkali metal dialkyldithiophosphate samples. The article estimates beneficiation indices when using the reagent M-TF and its mixture with IMA-I413 and xanthogenate. On the basis of undertaken studies it was found that application of the mixture of IMA-I413 collectors with butyl xanthate at the ratio of 5 : 1 and the feed ratio of 20 + 5 g/t made it possible to increase the extraction into the copper concentrate: Cu by 0,79 %, Au by 4,1 % and Ag by 2,4, while the sulfide concentrate yield decreased by a factor of 2. The disadvantage of this reagent composition is the increase in As content in the copper concentrate by 0,67 %. Of all tested dialkyldithiophosphate samples, the best incremental indices of copper and noble metals recovery were obtained when using the BTF-1552collector. The extraction into the copper concentrate increased: Cu by 1,9 %, Au by 3,2 %, and Ag by 1,8 %, while the sulfide concentrate yield decreased by 1,4 times. The increase in As content in the copper concentrate was 0,34 %.

The article proposes a recycling scheme for dusty waste generated during the metallurgical brass production with the use of two-stage leaching. During the first stage, when the dust is dissolved by a 0,5 mol/l sulfuric acid solution, a product solution containing the major amount of zinc ions (0,46 mol/l) and a small amount of copper ions (less than 0,02 mol/l) is obtained. Copper is sequentially electrochemically isolated from this solution, at a current density of 0,1 A/dm2, and then zinc is isolated at 5,0 A/dm2. The dry residue (cake) is subjected to copper-ammonia leaching, as a result of which all copper passes into the solution, and associated metals remain undissolved. In order to extract copper from the resulting solution, the liquid extraction by a 0,34 mol/l DH-510A solution in kerosene is used. Copper ions are extracted from the organic phase through re-extraction by a 2,0 mol/l sulfuric acid solution. The cathode copper is extracted from the obtained sulfuric acid electrolyte at current density of 1,5–2,0 A/dm2. The advantages of the proposed scheme are the increase in environmental friendliness through the use of solution recirculation at all stages of the process, as well as waste minimization through the entire process of dusty metallurgical sludge recycling.

The sulfide method for purification of sulfuric acid production flush waters have such disadvantages as the formation of finely dispersed (0,3 to 1,5 μm particle size) difficult-to-filter precipitates of arsenic sulfide (III) and the risk of hydrogen sulfide release into the atmosphere in case of sodium hydrosulfide overdose. The article studies the process of arsenic sulfide sols coagulation in order to develop a more effective and fast precipitate filtration technology. The article determines filtering rates in various modes of sodium hydrosulfide feeding, and dependence of the settling and filtering rates on the presence of coagulants – iron sulfate and aluminum sulfate. It was found that the implementation of dispersed feeding of sodium hydrosulfide during the arsenic sulfide precipitation in combination with the use of inorganic coagulant – ferric sulfate (III) would make it possible to increase the size of As2S3 particles by several times, and to increase filtering and settling rates of pulps.

The article studies the dynamic sorption of indium ions from polycomponent solutions with pre-reduced iron (III) containing, g/dm3: 0,084 In3+, 6,2 Fe2+, 67,0 Zn2+ and 19,6 H2SO4, on the Metosol reagent. The latter is a montmorillonite with the following composition (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2(H2O)n, modified by di(2-ethylhexyl) phosphoric acid. Its absorption dynamics of metal ions was studied by the method of frontal chromatography. The article determines the values of working (DEC) and total (TDEC) dynamic exchange capacities of the mineral sorbent depending on the specific throughput rate and the eluent temperature. The article justifies and calculates the basic parameters of the sorption technology of selective indium extraction from process solutions used for zinc production operations on the Metosol reagent in columns with subsequent desorption of metal by hydrochloric acid solution (1 : 1).

The article reviews the experimental melting of an intermetallic titanium alloy in a vacuum induction melting unit equipped with a «cold crucible» and manufacturing of gas turbine engine blades by investment casting in a centrifugal field. It studies the structure of the initial charge blank intended for melting the intermetallic titanium alloy, and analyzes its chemical composition. The article presents the casting process parameters and results of the metallographic analysis of manufactured blades. It was found that the structure of the cast blade is lamellar and consists of phases γ and α2. The article provides the mechanical test results. It was found that the ultimate tensile strength was σв = 765 MPa, the yield point was σт = 726,5 MPa, the relative elongation was δ = 1,6 %. The article studies the stress distribution along the blade feather and constructs distribution diagrams. Blade samples were tested for long-term strength (t = 650 °C, τ = 500 h), fatigue strength, and impact strength.

The paper considers the possibility of using boriding media based on boron carbide additionally containing chromium, titanium and silicon, for the diffusion hardening of titanium alloys. As a comparison, boriding is conducted in amorphous boron. The paper studies the microstructure, elemental and phase composition of OT4 titanium alloy diffusion coatings produced by saturation in powder media. Hardening boride layers based on titanium alloy are obtained from saturating media based on amorphous boron and multicomponent mixtures based on boron carbide. In all cases, coating phase composition corresponds to TiB, Ti2B5 and Fe2Ti phases. It is found that 30 to 150 μm thick coatings are formed from powder mixtures by means of diffusion process in the conditions of solid-phase titanium saturation. The paper studies temperature-time conditions of OT4 titanium-based boride layer formation from powder saturating media, and determines optimum modes for functional boride coating formation. The optimum temperature range for the processes of thermochemical titanium borating (900–1150 °C) is determined along with saturation time (2,5 to 5 hours). The paper specifies the maximum thickness of a functional boride coating based on the OT4 titanium alloy: from 180 μm in case of saturation from Bamorph to 240 μm for a mixture of 50%B4C + 20%SiC + 25%CrB2 + 5%NaCl at 950 °C and a saturation time of 4 hours. It should be noted that the maximum coating thickness is the one retained on the surface of the hardened sample.

The process of superplastic forming of a circular membrane under constant pressure is analyzed. The analytical process model is built based on principal assumptions of the thin shell theory, and two simplified approaches known from the literature and based on the hypothesis on the uniform thickness of a shell along its profile, and the uniform stretching of a meridian passing the dome apex. The methods of calculating the duration of superplastic forming of a circular membrane are considered. The finite element modeling of the process considered is made using the educational version of ANSYS software. The paper considers two boundary value problems stated in terms of superplasticity mechanics – the theory of creep and the theory of viscoplasticity. The results of analytical formula calculations are compared with the solutions of boundary value problems in terms of the creep and viscoplasticity theories obtained in the ANSYS software environment. The material constant values are determined from the results of uniaxial tests and test forming of Ti–6Al–4V titanium alloy. It is shown that test forming used to identify the material model provides much more appropriate results with the evaluation error reduced from ~20 % (when identifying the model based on the results of standard uniaxial mechanical tests) to ~3 %.