Experimental studies were conducted on the flotation of low-sulfide copper-nickel ore containing flotation-active magnesium silicates, specifically talc, using organic polymeric anionic reagents containing carboxyl and hydroxyl groups as depressants. The following reagents, which contain carboxyl groups, were examined: carboxymethyl cellulose and carboxymethylated starch; polyacrylic acid and its derivatives; sodium humate. Copolymers of ethylene oxide with ethylenediamine and glycerol containing hydroxyl groups were also investigated. The objective of this study was to identify new efficient domestic depressants for flotation-active silicates, selectively acting in the flotation of low-sulfide copper-nickel ore, in comparison with the performance of foreign Depramin 347 depressant. The impact of depressant reagents on the surface properties of talc was determined by the values of air bubble detachment force and electrokinetic potential. It was observed that for reagents containing carboxyl groups, the depressing effectiveness decreased in the following order: carboxymethyl cellulose → carboxymethylated starch → polyacrylic acid → sodium humate. This reduction was attributed to a decrease in the acidic properties of the reagents, a decline in their adsorption affinity for talc, and a decrease in the proportion of active carboxyl groups participating in the formation of the electrokinetic potential. Furthermore, a trend towards increased depressing ability was noted for carboxymethyl cellulose samples with an increasing degree of substitution. In contrast, reagents containing hydroxyl groups had virtually no depressing effect on talc. The data obtained support the use of domestic industrial samples of carboxymethyl cellulose, namely CMC 7N and PAC-N, as depressants for floating silicates, particularly talc, which is a detrimental impurity in the concentrate. 

This paper presents the results of studies on the reduction of dispersed cobalt and nickel metal powders from their salts in ammonia-alkaline aqueous solutions under hydrothermal autoclave conditions. A unified and environmentally friendly method for producing these powders has been developed. Hydrazine hydrate, with a 25–50 % excess of the stoichiometric ratio, was used as a reducing agent. This choice allows for obtaining metal phases that are chemically uncontaminated by decomposition products. The experiments determined the conditions for the quantitative reduction of cobalt (II) and nickel (II) ions from ammonia-alkaline aqueous solutions. The synthesis temperature for the dispersed phases ranged from 110 to 155 °C. It has been demonstrated that under the conditions used, the process is completed quantitatively within 60 min. Metal concentrations in the solutions were determined using atomic absorption spectroscopy. The results of the X-ray phase analysis confirm that cobalt forms in the HCP lattice, while nickel forms in the FCC lattice. No other phases, including X-ray amorphous phases, were observed. It was found that with an increase in the hydrothermal synthesis temperature from 110 to 155 °C, the specific surface area of cobalt increased by more than 1.5 times, and that of nickel black powders increased by approximately 2 times. Scanning electron microscopy revealed that cobalt is formed in the shape of lamellar particles with a lateral size of about 500 nm and a thickness of 50 nm, which aggregate into fractal structures. Nickel is represented by spherical particles arranged in chain-like structures. Using X-ray photoelectron spectroscopy, it was determined that the surface of the materials is covered with oxidized forms. The surface atomic concentration of cobalt (0) was approximately 2 %, while that of nickel (0) was about 25 %. 

The study investigated the feasibility of oxidative leaching rhenium in the presence of hydrochloric acid from machining waste (grinding waste) derived from products made of ZhS-32VI, a nickel-based heat-resistant alloy containing rhenium. This was achieved through agitation leaching process. The grinding waste fraction size of –0.071 mm, which accounted for the highest yield (49.2 wt.%), was utilized in the experiments. The rhenium leaching process was conducted in two variations: in the first option, grinding waste was mixed with a hydrochloric acid solution at ~100 °C, followed by the addition of hydrogen peroxide to the leaching solution after it had cooled; in the second option, leaching was performed using a hydrochloric acid solution with the gradual addition of hydrogen peroxide solution. The highest degree of rhenium leaching (91.0 %) was achieved in the first option. In this case, the initial concentration of hydrochloric acid was 8 M, and the molar ratio of the added reagents was ν(HCl): ν(H₂O₂) = 2.7 : 1.0. The kinetics of nickel leaching using a 6 M hydrochloric acid solution at 70 °C, with a solid-to-liquid phase ratio of 1 g : 50 ml, was also examined. The analysis of the kinetic data, processed using the “contracting sphere,” Ginstling–Brounshtein, and Kazeev–Erofeev models, indicates that the nickel leaching process occurs within the kinetic region. Additionally, the kinetics of rhenium leaching from the solid residue obtained after the hydrochloric acid leaching of nickel from grinding waste was investigated. Employing the same kinetic models to analyze the data, it was determined that the limiting stage of this process involves the diffusion of hydrogen peroxide within the rhenium-containing solid residue. 

The article discusses the solidification and phase composition of the (wt.%) Mg–4.8Gd–2.1Nd–1.6Y–0.4Zn–0.6Zr (GEWZ522K) casting alloy. It is demonstrated that in the as-cast state, the alloy structure comprises primary zirconium particles, dendrites of the magnesium solid solution (αMg), and eutectic intermetallic phases located between dendritic branches. Following solution heat treatment at t = 530±5 °C, the alloy transitions into a single-phase state and can be significantly strengthened through artificial aging after quenching. It is recommended to apply alloy aging at t = 250 °C for 8–10 h or at t = 200 °C for 15–18 h. This approach leads to the maximum strengthening of the alloy, with the best mechanical properties achieved for the alloy aged at t = 250 °C. Regardless of the aging method used, the ultimate tensile strength (UTS) of the samples surpasses 300 MPa, which significantly exceeds that of commercial casting alloys according to GOST 2856-79. The measured corrosion rate for the GEWZ522K alloy is 7.5±0.4 mm/year, that slightly higher than that for the less alloyed commercial alloy ML10 (approximately 2.5 mm/year) tested under similar conditions. Furthermore, the alloy was subjected to tests for ignition resistance when in contact with air. It was observed that with continuous airflow over the specimen’s surface, ignition centers appear at t = 625 °C due to the breakdown of the oxide film, causing the alloy to nearly completely melt. Therefore, the GEWZ522K alloy can be employed as a high-strength casting alloy. However, during the operation of cast parts, particular attention must be paid to safeguarding the surface of these parts against corrosion. 

This study investigates the impact of titanium addition to the eutectic silumin AK12 melt, considering various methods of addition. The research results encompass the sole introduction of titanium (at a calculated amount of 0.1 wt.%) through different forms/methods, such as the Al–4%Ti ligature, TiO₂ oxide, K₂TiF₆ salt, and Ti sponge. Additionally, the study explores the combined addition of titanium and a standard flux (comprising 62.5 % NaCl + 12.5 % KCl + 25 % NaF). The research involved qualitative and quantitative analyses of macro- and microstructures, spectral analysis data, and mechanical properties (tensile strength and relative elongation) of the alloys. The findings highlight that titanium has a positive influence on the structure of eutectic silumin, with the most effective results achieved when combined with the standard flux. However, the efficiency of silumin modification with titanium varies depending on the method of addition. Specifically, the introduction of titanium in the form of K₂TiF₆ fluoride salt, Al–4%Ti ligature, and titanium sponge positively affected macro grain refinement, reduced the spacing between the secondary dendrite arms of the solid solution (α-Al), and enhanced the dispersion of eutectic silicon. The most promising approach for complex silumin modification involves the joint introduction of titanium-containing substances and a sodium salt-based flux. This combination has a multifaceted impact on the silumin structure, leading to the simultaneous modification of various structural components in aluminum–silicon alloys. Depending on the type of titanium-containing substance, when processed alongside flux, the alloy achieves a relative elongation ranging from 9.7 % to 11.1 %, exceeding the same parameter for the unmodified alloy by more than 4 times and surpassing the sodium-modified alloy's relative elongation by 17–37 %. Furthermore, the ultimate strength reaches levels of 171–193 MPa, representing a 22–38 % improvement compared to the unmodified alloy and a 7–21 % increase compared to the sodium-modified alloy. 

The study employed high-temperature X-ray diffraction, quantitative phase analysis, and tensile mechanical property measurements to investigate the relationship between coefficient of thermal expansion (CTE) and phase composition, along with the average yield strengths and Young's moduli of Al–Cu–Li alloys in three different sheet orientations: 1441, V-1461, V-1469, V-1480, and V-1481. The copper content within the solid solution and the mass fractions of the T₁(Al₂CuLi) and δ′(Al₃Li) phases were determined using an innovative technique based on measuring the lattice distance of the α solid solution, Vegard's law, and balance equations for the elemental and phase compositions of the alloys. It was observed that as the lithium-to-copper ratio in the alloys increased from 0.32 to 1.12, the proportion of the δ′(Al₃Li) phase increases from 6.3–8.4 wt.% in V-1481, V-1480 and V-1469 alloys to 16.0–17.3 wt.% in 1441 and V-1461 alloys, accompanied by a decrease in the T₁(Al₂CuLi) phase from 5 to 1 wt.%. This led to an increase in the Young's modulus from 75 to 77 GPa due to higher overall proportion of intermetallic compounds and a reduction in yield strength from 509 to 367 MPa due to the decrease in the T₁ phase. This decrease in yield strength resulted from the fact that the hardening effect of the T₁ phase was 3–4 times greater than that of the δ′ phase, and this couldn't be offset by an increase in the total intermetallic compound proportion. The observed increase in Young's modulus indicated that the elastic properties of the intermetallic phases were similar, and the rise in the total fraction of intermetallic compounds compensated for the decrease in the T₁ phase. Furthermore, it was demonstrated that СTE, as measured based on the thermal expansion of the solid solution, also depended on the characteristics of the intermetallic phases present in the alloy. This expanded the potential interpretations of СTE measurement results. 

In this study, an integrated treatment approach was employed to modify hypereutectic silumin. This method involved electroexplosive alloying of the surface layer with yttrium oxide powder, followed by irradiation with a pulsed electron beam. The experimental data obtained demonstrate that this integrated treatment results in the formation of a submicron-nanocrystalline structure characterized by high-speed cellular crystallization of aluminum within the surface layer. This structure is composed of crystallization cells enriched with aluminum atoms, indicating the creation of a solid solution based on aluminum. The nanocrystalline layers, formed by silicon particles and yttrium oxide, are positioned at the cell boundaries. The study reveals that, as a consequence of integrated treatment with an electron beam energy density of 25 J/cm2 , the wear parameter of the modified samples increases by 7.9±0.6-fold, and the friction coefficient decreases by 1.7±0.15-fold compared to the initial state. Additionally, the microhardness of the modified silumin surface layer increases by 1.5±0.12-fold compared to the initial state. When the electron beam energy density is elevated to 35 J/cm2, the wear parameter of silumin is enhanced by 2.1±0.21-fold, while the friction coefficient increases by 1.13±0.1-fold. However, the microhardness decreases by 1.3±0.13-fold, while still surpassing the specified characteristics of untreated silumin. This investigation postulates that the substantial increase in the wear parameter during integrated treatment may be attributed to the presence of silicon inclusions in the surface layer that did not dissolve during the modification process. These inclusions are surrounded by the high-speed cellular crystallization structure mentioned earlier.