Government Information Quarterly

Kolmachikhina E.B., Kolmachikhina O.B., Yankina Y.A., Golibzoda Z.M., Brizhevataya P.A., Sedel’nikova D.S., Khabibulina R.E.

The study investigates the physicochemical patterns of tin leaching from the surface of glass substrates from decommissioned displays in hydrochloric, sulphuric, and methanesulphonic acids. The effects of acid concentration (0.1–1.0 N), duration (10–60 min), temperature (298–353 K), and ultrasonic treatment intensity (UST) (120–300 W/cm2) on leaching performance were evaluated. It was demonstrated that ultrasonic treatment positively impacts sulphuric acid leaching of tin, increasing its recovery by 14–16 %. However, during leaching in hydrochloric and methanesulphonic acid solutions, UST led to a reduction in tin recovery to 28 % and 1.7 %, respectively, due to acid decomposition under ultrasound. The partial reaction orders for tin leaching in HCl, H2SO4, and CH3SO3H were determined to be 0.8, 1.4, and 1.1, respectively, and changed to 1.5, 1.1, and 0.3 under ultrasound for the corresponding acids. An increase in temperature from 298 K to 333 K significantly improved tin recovery in sulphuric and hydrochloric acids. However, raising the temperature to 353 K led to a decrease in tin ion concentration after 10–20 min, likely due to tin hydrolysis and precipitation. The calculated apparent activation energies of tin oxide dissolution in HCl solutions were 40.4 kJ/mol without UST and 22.9 kJ/mol with UST. For H2SO4, the apparent activation energy was 4.0 kJ/mol, increasing to 29.0 kJ/mol under ultrasonic treatment. Therefore, the study showed that tin leaching from glass substrates of decommissioned displays proceeds in a kinetic regime when HCl is used and in a diffusion regime in H2SO4 solutions, with ultrasonic treatment facilitating the transition to a mixed regime.

Petrovskaya K.V., Timofeev P.A.

Currently, siliconized carbon-carbon composites (C/C composites) hold a significant position among materials used in nonferrous metallurgy. The process of Liquid Silicon Infiltration (LSI) for porous C/C composites is strongly inf luenced by their microstructural characteristics. Studying the effect of the porous structure of various C/C composites on the completeness of silicon infiltration can enable the regulation of the phase composition of siliconized materials over a wide range, as well as the physical, mechanical, and thermophysical properties of C/C–SiC composites. This paper presents the results of analyzing the porous structure and strength characteristics of C/C composites based on needle-punched preforms with different types of carbon matrices (pyrocarbon, natural and synthetic pitch coke, and phenol-formaldehyde resin coke) and the C/C–SiC composites derived from them. Due to the specific features of carbon matrix formation from liquid or gas phases, differences in pore size distribution were observed. A carbon matrix formed by the gas-phase method exhibits fewer nanoscale pores compared to one formed by the liquid-phase method. The inf luence of the pore structure and the nature of the matrix carbon in various needle-punched preforms on the degree of saturation during LSI, infiltration depth, and mechanical properties was determined.

Kolesnikov A.V., Ageenko E.I.

The article focuses on researching the technology of cementation purification of zinc sulfate solutions from impurities that adversely affect the electrolysis of zinc. The purpose of this work is to explore new approaches for deep cementation purification of solutions, aimed at reducing the consumption of zinc dust and activating additives (antimony and copper compounds) in the technological process, while improving the quality of the purified solution by decreasing the content of cobalt, nickel, and cadmium in the solution supplied for zinc electrolysis. In this study, a new technology for the cementation purification of industrial solutions was developed, which includes the following stages of impurity removal using zinc dust: preliminary purification stage to remove copper to a concentration of 90–110 mg/L; co-precipitation of copper, cadmium, cobalt, and nickel with the addition of antimony trioxide; deep purification of the solutions from all impurities remaining after the first stage. The purification process was conducted under the following conditions: the preliminary deposition took place at a temperature of 50 °C, with a duration of 30 min and a zinc dust consumption of 0.2–0.4 g/L; the first purification stage occurred at a temperature of 80 °C, for a duration of 1 h, with a zinc dust consumption of 2–3 g/L, and an antimony dosage of 3–6 mg/L; the second purification stage was carried out at a temperature of 75–80 °C, for a duration of 1 h, with a zinc dust consumption of 2–3 g/L, and dosages of copper sulfate and antimony at 50 mg/L and 2–3 mg/L, respectively.

Sokolov A.Y., Kasikov A.G.

Chalcopyrite (CuFeS2) is one of the primary minerals processed on an industrial scale for copper production and often dominates copper concentrates sent for pyrometallurgical processing. This study demonstrates the efficient and selective extraction of copper from chalcopyrite concentrate through sulfating roasting, sulfuric acid leaching, and solvent extraction. At a roasting temperature of 700 °C for 1.5 h, chalcopyrite fully decomposes into hematite (Fe2O3) and chalcanthite (CuSO4). Leaching the calcine with a 0.02 M sulfuric acid solution transfers most of the copper to the aqueous phase, while iron concentrates in the solid residue. Additionally, precious metals concentrate in the residue after leaching of the calcine, with the following content in g/t: Pd – 41.61, Pt – 5.65, Ag – 96.22, Au – 4.81. The removal of iron from the leach solution using solvent extraction with di-2-ethylhexyl phosphoric acid was highly effective: with a 25 % extractant solution and an organicto-aqueous ratio of 1:1 over two stages, the iron concentration in the aqueous phase dropped from 3.05 to 0.01 g/dm3, and with an organic-toaqueous ratio of 1:2 over four stages, it decreased to 0.006 g/dm3. After iron purification and solution evaporation, copper sulfate was obtained with the following composition (%): CuSO4·5H2O – 99.84 (equivalent to 25.42 % copper), Ni – 0.014, Al – 0.007, Fe – 0.0003, As – 0.0002.

Biryukova O.D., Mogilnykh A.E., Pesin A.M., Pustovoytov D.O., Pesin I.A., Biryukov M.A.

Asymmetric rolling of aluminum alloys is one of the methods for improving their mechanical and performance characteristics. Kinematic asymmetry during rolling is achieved by varying the roll speed ratios (V1 /V2). It is believed that when V1 /V2 > 3, the process of asymmetric rolling, by combining significant compression and shear deformations, approximates the processes of severe plastic deformation. It has been found that the majority of studies are based on data obtained within a limited roll speed ratio range, V1 /V2 < 2, in asymmetric rolling. This article examines the effects observed at V1 /V2 = 1÷7.7. The implementation of this condition became possible thanks to a unique scientific facility – the 400 laboratory-industrial asymmetric rolling mill at the Zhilyaev laboratory “Mechanics of Gradient Nanomaterials” at Nosov Magnitogorsk State Technical University Experiments were conducted on asymmetric thin-sheet rolling of aluminum alloys 2024, 5083, and 6061, as well as accumulative roll bonding to produce laminated sheet aluminum composites 5083/2024, 5083/1070, and 6061/5083. The disadvantages of asymmetric rolling compared to symmetric rolling were identified: sample failure was observed at single relative reductions of 37 % for layered sheet aluminum composites (5083/2024) and 40 % for thin-sheet aluminum alloys (6061). The nuances of material preparation for processing were described, including the necessity of cleaning and degreasing the alloy surfaces before bonding into a composite. The rolling temperature regimes were selected, determining cold asymmetric thin-sheet rolling (room temperature processing) and warm asymmetric accumulative roll bonding (heating of the workpieces in the furnace before rolling at 320–350 °C). A reduction in rolling force (by a minimum of 1.3 times), the ability to vary hardness (including an increase by a minimum of 30 %), and technological plasticity with changes in the roll speed ratios within the range of 2 to 7.7 were demonstrated. Options were proposed for reducing the processing cycles of aluminum alloys without compromising the quality of the finished product by reducing the number of rolling passes and annealing steps in the standard process scheme.

Novikova O.S., Salamatov Y.A., Kostina A.E., Volkov A.Y.

A copper alloy with small additions of palladium and silver (Cu–1.5Pd–3Ag (at. %))—which has potential applications as a corrosionresistant conductor of weak electrical signals—was studied using X-ray diffraction analysis, microhardness measurements, specific electrical resistivity, and tensile mechanical properties tests. Samples were examined in several initial states: quenched (from 700 °C) and deformed at room and cryogenic temperatures (with a 90 % reduction in cross-sectional area in both cases). To study the processes of structural reorganization and property evolution, the initial samples were annealed in the temperature range from 150 to 450 °C (in 50 °C increments), followed by cooling in water or air. The duration of the heat treatments ranged from 1 to 48 hours. It was established that annealing the Cu–1.5Pd–3Ag alloy at temperatures below 450 °C leads to the precipitation of silver-based phase particles in the Cu matrix. Annealing of the initially quenched alloy was found to slightly increase its specific electrical resistivity (ρ) from 3.55·10–8 to 3.8·10–8 Ohm·m (after 48 h at 250 °C). It was revealed that alloying copper with 1.5 at. % palladium and 3 at. % silver enhances the strength properties (the yield strength of the alloy reaches 500 MPa) and raises the recrystallization temperature, while the electrical conductivity of the alloy remains around 50 % IACS. The optimal combination of properties (strength, ductility, and electrical conductivity) is observed after annealing the pre-cryodeformed alloy at 250 °C for less than 18 h. Extending the annealing time causes overaging, resulting in softening. The results of this study can be applied in the development of a new high-strength material with reduced electrical resistivity.

Solodovnikova P.A., Mashkovtsev M.A., Rychkov V.N., Ginko G.V., Telegin T.E., Ugryumova M.V.

Aluminum oxide is widely used as a catalyst carrier, including in internal combustion engine systems, where operating temperatures exceed 1000 °C. As such, aluminum oxide must exhibit enhanced thermal stability. This property is linked to the presence of pentacoordinated centers on the surface of the γ-phase of Al2O3. This paper examines the effect of the pH during aluminum hydroxide precipitation on the formation of pentacoordinated centers on the surface of aluminum oxide. The samples of aluminum hydroxide were synthesized via controlled double-jet precipitation, followed by thermal decomposition into oxides. Precipitation was carried out at constant pH levels, and for comparison, parallel samples were synthesized at pH values of 5, 6, 7, 8, and 9. The precursors for precipitation were a 1 M aluminum nitrate solution (Al3+) and a 10 wt. % ammonia solution (NH4OH). The solutions were introduced into the reactor in a dropwise mode with continuous stirring. The resulting aluminum oxide samples were analyzed using X-ray diffraction and nuclear magnetic resonance techniques. The data show a direct correlation between the pH of aluminum hydroxide precipitation and the presence of pentacoordinated centers on the aluminum oxide surface: the higher the pH, the lower the content of pentacoordinated atoms. Additionally, a relationship was observed between the pH value and the size of the coherent scattering region, with an increase in coherent scattering observed at higher pH levels.

Dudarev V.I., Dudareva G.N., Yakovleva A.A.

A significant portion of the world’s reserves of Ni-containing raw materials (40–66 %) is concentrated in oxidized nickel ores. One of the alternatives to the high-cost pyrometallurgical and ammonia-carbonate methods for processing such ores could be the chlorammonium recovery of nickel from relatively low-grade ores. The halide-ammonia decomposition and recovery technology of nickel from oxidized nickel ores, supplemented by a sorption process, is less stage-intensive and simpler in practical implementation. Nickel adsorption recovery is feasible using carbon sorbents that exhibit high chemical stability, withstand high-temperature exposure, and strong acidic treatment. Sorbents were obtained through steam-gas activation of extracted carbonizates from fossil coals. The sorption capacity for Ni(II) ions was studied, and the patterns and characteristic parameters of the process on carbon sorbents were identified using adsorption isotherms while varying experimental conditions. The experimental results were processed using the Freundlich and Langmuir equations. The sorbents have several distinctive features determined by their predominant microporous structure and multifunctional surface with active complex-forming atomic groups, characteristic of ampholytes with cation- and anion-exchange properties. The adsorption process is described by a pseudo-first-order equation with rate constants ranging from 0.204 to 0.287 s–1. For the adsorption recovery of Ni(II), a scheme with two adsorbers and a pseudo-fluidized sorbent bed is proposed. Nickel desorption and sorbent regeneration were carried out with a 2.3 % sulfuric acid solution, desorbing 95 to 98 % of nickel. Standard chemical machinery and equipment are recommended for these processes. 

Rychkov V.N., Kirillov E.V., Kirillov S.V., Bunkov G.M., Botalov M.S., Smyshlyaev D.V.

The paper investigates the extraction of rare earth elements (REE) from technogenic sources – phosphogypsum and uranium in situ leaching (ISL) solutions. We found that mechanical activation significantly increases the degree of REE leaching from phosphogypsum. We also obtained data on sorption leaching of REEs from phosphogypsum. It has been shown that, depending on the ion exchanger used and its form, chemical activation can double the leaching degree of the target components. The paper presents the findings of the study on the sorption recovery of scandium from uranium in situ leaching solutions. We determined that Sc sorption from uranium ISL solutions on the Purolite S-957 cation exchanger is much more effective than on Lewatit TP-260, Purolite S-950, Tulsion CH-93 CH-93, and ECO-10 ampholites. However, it should be pointed out that none of the listed sorbents is highly selective towards scandium ions. The paper presents comparative data on Sc extraction from uranium ISL solutions using Lewatit VP OC-1026 and Axion 22 commercial solid extractants synthesized according to the method described in the paper. We determined the mechanism of scandium extraction from uranium ISL solutions using Axion-22 and proved that it shows high selectivity towards scandium ions. Studies on the desorption of scandium from the saturated solid extractant showed that the most effective desorption agent is an aqueous solution of hydrofluoric acid. Additionally, the paper investigates the sorption extraction of REEs from uranium ISL solutions on cation exchangers KU-2, KM-2P, and KF-11. We found that the best eluents for the desorption of REEs from the saturated cation exchanger are solutions of calcium chloride and ammonium nitrate. It has been shown that the concentration of REEs in the solution and the removal of major impurities (Fe and Al) are quite effective when REEs precipitate from the desorption solution by fractional hydrolysis. The paper describes the separation of La, Nd, and Sm by elution from the saturated impregnate containing phosphorylpodande and Di(2-ethylhexyl) phosphoric acid in its structure. It should also be noted that ionic liquids can be useful for the extraction of REEs from the solutions of various electrolytes. We presented one of the technological schemes illustrating REE extraction from phosphogypsum.

Aleynikov S.A., Belousova N.V.

The article explores the possibility of obtaining lithium carbonate from the black mass – an intermediate product of lithium-ion batteries recycling. X-ray phase analysis and inductively coupled plasma atomic emission spectrometry of the black mass revealed that it contains 3 % lithium. It has been established that during water leaching, 40 % to 70 % of lithium can be selectively extracted from the black mass into the aqueous phase at L/S ratios ranging from 10 to 200. During water leaching, kinetic curves were recorded at temperatures of 25 °C and 80 °C. To remove Al ions from the leaching solution, we studied the sorption of aluminate ions on weaky basic (AN-31, CRB05) and strongly basic (A500) anion exchangers under static conditions using a model Li–Al solution. It was demonstrated that in an alkaline environment, strongly basic anion exchangers with quaternary amino groups are not able to adsorb Al ions, while AN-31 and CRB05 with hydroxyl clusters in their functional groups have a capacity of 2 to 3 g/dm3 in terms of aluminum ions. The sorption of aluminum from the model Li–Al solution was conducted under dynamic conditions using the CRB05 anion exchanger (N-methylglucamine) at specific flow rates of 2 and 4 column volumes per hour. Elution sorption curves were plotted, and both the dynamic exchange capacity and the total dynamic exchange capacity were determined. Additionally, we showed that aluminum ions can be removed by sorption so that their residual concentration in the raffinate drops below 0.5 mg/dm3. Sorption purification of the solution after water leaching of the black mass was performed using a weaky basic anion exchanger Diaion CRB05 and a chelate cation exchanger Purolite S950. After evaporation of the purified solution, we obtained lithium carbonate with a main substance content of 98.2 %.

Fatykhova N., Kuptsov K.A., Sheveyko A.N., Gizatullina A.R., Loginov P.A., Shtansky D.V.

High-entropy coatings are highly promising for protecting steel parts in coastal and marine infrastructure from corrosion and tribocorrosion. This study examines the properties of medium- and high-entropy Fe–Co–Cr–Ni–(Cu) coatings produced by vacuum electrospark deposition. The coatings, with thicknesses of up to 30 μm and varying copper content, exhibit a single-phase solid solution structure with an FCC lattice and a dense, homogeneous morphology. The addition of 14 at.% Cu was found to enhance corrosion resistance, shifting the corrosion potential to 100 mV. In friction conditions within artificial seawater, the inclusion of copper also improved tribocorrosion properties, raising the corrosion potential during friction to –165 mV. This improvement is attributed to the galvanic deposition of dissolved copper on the worn areas of the coating, which also reduces the friction coefficient from 0.37 to 0.26. The Fe–Co–Cr–Ni–(Cu) coatings demonstrate high wear resistance, ranging from 5.6 to 9.6·10–6 mm3/(N·m). The findings confirm the potential of these coatings for applications in environments subject to both friction and corrosion.

Elshin V.V., Mironov A.P., Lisitsyna A.A.

This paper presents the results of theoretical and experimental studies on the process of gold adsorption from cyanide solutions onto activated carbon (AC). One of the objectives of the study was to identify the functional relationship between the mass loading of AC in the volume of the adsorption column solution and the kinetics of the process. To achieve this, a modified adsorption kinetics equation (considering the heterogeneity of the process) was proposed, which incorporates the solid phase of the carbon sorbent in the unit volume of solution as a third intermediate agent of adsorption interaction between the adsorbate ions and the free active sites of the AC. As a result, a modified third-order adsorption kinetics equation for gold adsorption on AC was derived, taking into account the solid phase loading of AC in the solution volume, along with its analytical solutions under conditions of constant gold content in the initial solution and the process conducted in a closed volume with varying gold concentrations in the solution according to the material balance equation. The relationship between the solutions of the kinetic equation and the adsorption isotherm equation was established. From the solutions of the kinetic equation, a modified Langmuir isotherm equation was derived, which allows determining the equilibrium concentrations of gold on the AC and in the solution a priori under the condition that the process is conducted in a closed volume, with known initial gold contents in the solution and on the AC, as well as with a known AC loading in the adsorber volume. The theoretical dependencies of the adsorption and desorption rate constants on temperature, convective, and diffusion parameters are discussed. The presented mathematical model of adsorption kinetics is valid under the conditions of gold adsorption on AC from gold cyanide solutions with an adsorption time of up to 2 days and a sorbent capacity utilization degree of 40–60%.

Koshmin A.N., Zinoviev A.V., Cherkasov S.O., Tsydenov K.A.

An analysis was performed on the temperature, rate and force parameters of the hot cladding process for the experimental Al–2%Cu–2%Mn alloy with technically pure aluminum grade 1050A, as well as on the stress-strain state of the metal in the deformation zone at reductions of 30, 40, and 50 %. Plastometric tests were conducted within the temperature range of 350–450 °C, strain rates of 0.1–20 s–1, and true strain of 0.1–0.9, and coefficients for calculating the flow stress of the experimental alloy were determined. The thermal conductivity of the Al–2%Cu–2%Mn alloy under hot deformation conditions at temperatures of 350, 400, and 450 °C was theoretically calculated to be 161, 159, and 151 W/(m·K), respectively. The study of the cladding process on a two-high rolling mill was carried out using the QForm finite element simulation software. It was found that when the metal of the cladding layer comes into contact with the roll, its temperature decreases by approximately 100 °C, with the temperature across the height of the composite equalizing within 20–30 ms after exiting the deformation zone. The rolling force is evenly distributed between the two rolls in all cases considered, while the rolling torque on the roll on the cladding layer side is half that on the roll contacting the base layer, which is characteristic of asymmetric rolling. Points characterized by optimal bonding conditions of the rolled layers were identified, located at 10 % and 70 % of the deformation zone length along the rolling axis, where normal stresses significantly prevail over shear stresses. It was determined that the formation of these areas is due to the nature of plastic flow, including the presence of a non-deforming hard layer and a sticking zone.

Vydysh S.O., Bogatyreva E.V.

The relevance of replacing the slime–H2SO4–H2O system used for processing slimes from secondary copper electrolytic refining (SCER) with a slime–NH3·H2O–(NH4)2SO4–H2O system has been substantiated. Comprehensive studies of the characteristics of SCER slime samples were conducted. It was found that about 90 % of the copper is distributed between the Cu2O phase and other phases, with a total copper content of 55.12 %. A new phase, Cu4(OH)6SO4, corresponding to the mineral brochantite, was discovered, with a content in the slime of 6.40 %. Silver, with a concentration of 2.43 % in the slime, is present in metallic form at 69.1 %, with the remainder in the form of AgCl. The contents of associated components PbSO4, BaSO4, and SnO2 are 13.52 %, 9.33 %, and 4.73 %, respectively. To substantiate the feasibility of low-temperature hydrometallurgical opening of the slime components and the conditions necessary for its implementation, determined by the specific qualitative and quantitative compositions of the slime, a thermodynamic analysis of the slime–NH3·H2O–(NH4)2SO4–H2O system was performed. This analysis allowed for the discovery and mathematical description of the dependencies of copper leaching indicators on the composition of the ammonia-ammonium mixture (ammonia buffer). A nomogram for the theoretical calculation of the minimum excess NH3·H2O/NH4+ over the stoichiometrically necessary amount required for the complete formation of the copper ammine complex was constructed according to the equilibrium ammonia-ammonium solution's pH and copper concentration. Thermodynamic calculations determined the optimal composition and consumption of ammonia-ammonium solutions, as well as the characteristics of the leach pulp, such as the concentration of [Cu(NH3)4]2+ and the redox potential. Technological studies demonstrated the possibility of effective and selective extraction of copper from SCER slimes at a rate of no less than 99 % in the slime–NH3·H2O–(NH4)2SO4–H2O system, which was confirmed experimentally. Studies of the kinetics of copper leaching from slime in the slime–NH3·H2O–(NH4)2SO4–H2O system were conducted. The activation energy of the ammonia-ammonium copper leaching process from SCER slime (Ea = 5±0.25 kJ/mol) was determined within the temperature range from 15 to 45 °C at a total buffer system concentration [NH3·H2O] + [NH4+] of 1 and 2 mol/L, as well as the order of reaction at a temperature of 24±1 °C, which is 0.24±0.02 and 0.91±0.05 for [NH3·H2O] + [NH4+] concentrations above 1.5 mol/L and below 1.5 mol/L, respectively. A change in the kinetic mode of leaching with the limitation of the reaction rate by adsorption of reagents on the surface of solid particles to diffusion was detected when the total buffer system concentration [NH3·H2O] + [NH4+] was reduced below 1.5 mol/L. The equation for the formal kinetics of the investigated process in the slime–NH3·H2O–(NH4)2SO4–H2O system was determined.

Naumov S.V., Panov D.O., Chernichenko R.S., Sokolovsky V.S., Salishchev G.A., Alekseev E.B., Neulybin S.D., Belinin D.S., Shchitsyn Y.D., Lukianov V.V.

Using keyhole plasma arc welding, welded joints of a Ti2AlNb-based alloy, VTI-4, were obtained, and their structure and mechanical properties were studied. It has been established that the dynamic effect of a keyhole arc had a positive effect on the quality of the welded joint; namely, lack of penetration, porosity, and microcracks were eliminated. The welded joint consisted of a fusion zone (FZ), a heat-affected zone (HAZ), and a base metal (BM). Depending on the phase composition and morphology of the obtained phases, the HAZ can be divided into four zones: HAZ1 with large β-phase grains near the melting line, HAZ2 with large β-phase grains + α2, HAZ3 with more fragmented β-phase grains retaining more α2-phase, and HAZ4 with the phase composition β + α2 + O. Subsequent heat treatment (HT: quenching at 920 °C for 2 h, cooling in air, followed by aging at 800 °C for 6 h, cooling in air) preserved the zone structure of the weld but led to the formation of the O-phase within β-grains. The microhardness of the weld in the zone corresponds to 360±15 HV0.2, but after HT, it increased to 382±20 HV0.2. The strength properties of the welded joint after HT were above 90 % of the base metal (σucs = 1120 MPa, σ0.2 = 1090 MPa), while elongation to failure is close to the initial condition (δ = 2.1 %).