The most efficient selective reagent modes for the flotation of a copper–zinc pyrite ore from one of the Ural deposits have been developed, based on the use of compositions of metal-containing reagent modifiers in combination with sodium sulfide. The study analyzed the most effective conditions for separating copper and zinc minerals from pyrite during the bulk flotation of copper–zinc ore, as well as the conditions for improving the selective separation of the bulk copper–zinc concentrate. The influence of reagent–modifier compositions introduced into the bulk flotation cycle on the process parameters of selective flotation of the bulk concentrate was evaluated. The results of fractional analysis of the floatability of copper, zinc, and iron minerals were presented, taking into account the flotation kinetics and the distribution of these minerals in the floated concentrate by fractions: poorly floatable, moderately floatable, and easily floatable. The reagent–modifier compositions used not only depressed pyrite flotation but also ensured efficient separation of copper and zinc minerals into individual concentrates. It was found that the most effective selectivity in flotation separation of copper and zinc minerals was achieved by introducing a composition of ferrous sulfate and sodium sulfide into the bulk copper–zinc flotation circuit in equal proportions (50 and 50 g/t). As a result, a copper–pyrite concentrate containing 12 wt. % Cu with a copper recovery of 74.45 % and a zinc concentrate containing 5 wt. % Zn with a zinc recovery of 73.68 % from the ore were obtained. Analysis of flotation kinetics showed that the introduction of this reagent mixture contributed to the highest flotation rate of copper, ensuring a maximum copper recovery to the froth (copper–pyrite) product of 86.74 %.

The study describes a method for recycling the still residue from the synthesis of hexafluoro-1,3-butadiene (HFBD) to produce zinc phosphate in the form of Zn₃(PO₄)₂·2H₂O, which is used as a component in anti-corrosion pigment materials. The still residue (“heavy liquid”) is preliminarily subjected to deep vacuum distillation (residual pressure 30 Pa, final temperature 160 °C) to recover volatile solventsnamely, isopropanol and dimethylformamide (DMF). The remaining residue is a concentrated solution of ZnCl₂ (about 70 wt. %) containing approximately 10 g/dm³ of iron in the form of Fe(II) and Fe(III), as well as colored organic impurities of unidentified composition. According to the proposed process, the vacuum distillation residue is diluted with water at a ratio of 1 : 2, filtered to remove suspended solids, acidified to pH 2 by the addition of concentrated HCl, and treated oxidatively with H₂O₂ at 70 °C. Fe(III) is removed by extraction with a 30 % solution of Cyanex 272 in an aliphatic diluent, and the colored impurities are removed by adsorption onto BAU-1 grade activated carbon. An alternative method for removing Fe(III) and part of the colored impurities involves precipitating zinc in the form of (ZnOH)₂CO₃ using a 10 % Na₂CO₃ solution. Final clarification is also carried out using BAU-1 activated carbon. The purified, clear ZnCl₂ solution is then subjected to a twostep precipitation process to obtain zinc phosphate. The resulting precipitate is filtered, thoroughly washed with water, dried, and ground. The study showed that after drying at 100–105 °C, the resulting powder corresponds to the composition Zn₃(PO₄)₂·2H₂O. The content of regulated impurities falls within acceptable limits, and the properties of the material meet the requirements for pigment-grade substances. A comparison of the obtained zinc phosphate with a commercially available sample of pigment-grade zinc phosphate was conducted. It was established that the proposed technology yields 580 g of zinc phosphate dihydrate per 1 kg of initial raw material.

The process of fire refining of copper is based on the removal of impurities that have a high affinity for oxygen through their oxidation by gaseous oxygen. Since the main component of blister copper is copper itself, according to the law of mass action and its affinity for oxygen, during air blowing the metal primarily reacts with the oxygen in the blast. The resulting copper (I) oxide is transported from the zone of direct contact with gaseous oxygen into the region of lower oxygen concentration, where the oxidation of impurities (Mei) occurs. In practice, the actual copper melt deviates from ideal behavior; therefore, it is necessary to consider the activities of the components and the interaction parameters of the system when evaluating the thermodynamic premises of fire refining. It is known that the oxygen activity in copper melts depends on the oxygen affinity of the impurities. Impurities with a high affinity for oxygen (e.g., Al, Si, Mn) significantly reduce the oxygen activity, whereas those with a lower affinity (e.g., Zn, Fe, Sn, Co, Pb) only partially decrease it. Thermodynamic calculations were performed to estimate the final concentration of impurities in the copper melt and to theoretically evaluate the influence of impurities on oxygen activity in blister and anode copper. The calculations showed that fire refining of copper by air blowing under a weighted ideal slag has thermodynamic limitations. The final impurity concentration depends on both the oxygen activity in the melt and the activity of the impurity oxide in the slag. A decrease in the impurity oxide activity in the slag enhances refining efficiency by shifting the oxidation reaction equilibrium toward the reaction products. The theoretical effect of impurities on the oxygen activity in copper is substantiated for two melts differing in chemical compositin.

Using the QForm software package, a finite-element analysis was conducted to assess the technological feasibility of implementing a new cladding scheme for 360-mm-thick aluminum–lithium alloy 1441 ingots under the production conditions of PJSC “KUMP”. Instead of the traditional cladding scheme, in which the cladding plates are roll-bonded to the ingot over four passes with an absolute reduction of 6 mm per pass, the cladding plates are seated in pre-machined recesses milled into the top and bottom surfaces of the ingot and roll-bonded in a single pass with an absolute reduction of 24 mm. The analysis showed that the new cladding scheme prevents extrusion of the cladding plates from the ingot surface at high reductions, enabling the use of thinner plates (10 mm instead of the conventional 15 mm). The new approach also significantly reduces the total number of passes and inter-deformation pauses during rough rolling, thereby improving the thermal condition of the workpiece before finish rolling. A reduction of three passes and three pauses (10 s each) leads to an average temperature increase of approximately 23 °C. The deformation behavior of the base metal (alloy 1441) and the cladding layer (ACpl alloy) was analyzed. The mean accumulated strain in the ingot after rolling according to the new scheme was found to be twice as high as under the traditional scheme, while the deformation distribution within the cladding layer was more uniform. The obtained results can be used to enhance and optimize hot-rolling parameters for clad sheets and strips of aluminum– lithium alloy 1441 at PJSC “KUMP”.

The study investigates the structural and mechanical characteristics of permanent joints produced by laser welding of VT1-0/VT1-0 titanium alloys after cutting with a newly designed PMVR-5.3 narrow-jet plasma torch, which features a gas-dynamic stabilization (GDS) system with several design innovations. The improved GDS efficiency enhances cutting precision and surface quality, thereby increasing the radiation absorption coefficient, weld penetration, and overall laser-welding efficiency. Experimental results show that continuous-wave CO2 laser welding of VT1-0/VT1-0 plates forms a narrow weld with a structure corresponding to the as-cast state of the alloy and large equiaxed grains in the central part of the weld, which decrease in size toward the root compared with those in the surface region. Although gas shielding does not completely prevent the formation of fine micropores in the weld metal, their amount is insignificant; they do not form critical clusters within the microvolumes of the weld and have no adverse effect on the strength characteristics of the welded joint. The average microhardness of the weld metal was found to be higher than that of the base metal. According to tensile and microhardness testing, the weld metal demonstrates high strength, significantly exceeding that of the titanium alloy, and exhibits a ductile fracture morphology. Under cyclic loading, fracture occurred in the base metal rather than in the weld metal, with the fraction of the final rupture zones increasing as the maximum cyclic stress rose. The findings confirm the applicability of precision narrow-jet air-plasma cutting and continuous-wave CO2 laser welding technologies for producing VT1-0/VT1-0 welded joints with high efficiency and mechanical strength comparable to those of the base material.

This paper presents the results of a study on two titanium-based alloys — Ti–10wt.%Mo and Ti–15wt.%Mo — aimed at assessing their potential for use as base materials in implantable medical devices for osteosynthesis. The alloy samples were examined in three conditions: as-fabricated, after annealing at 1000 °C, and after high-pressure torsion. The microstructure of the alloys was analyzed using scanning electron microscopy and X-ray diffraction. The Young’s modulus, microhardness, and nanohardness values were measured, and the effect of the alloys on the viability and surface adhesion of human multipotent mesenchymal stromal cells during in vitro incubation was investigated. Comparative analysis of the obtained results revealed that the annealed Ti–15wt.%Mo alloy sample is the most promising candidate for orthopedic applications, as it exhibits an optimal combination of good biocompatibility, enhanced stimulation of cell adhesion, and relatively low microhardness (283 HV) and Young’s modulus (106 GPa).