The cold flow simulation of the Pobeda furnace bubbled bath hydro-gas dynamics was performed using the bottom lance in a protective gas shell. It was shown that gas infusion into liquid at Ar = 5÷60 is carried out in pulse-coupled mode. The gas-liquid interaction area was investigated at Ar = idem for separate and joint air egress through ring and round nozzles. A two-phase zone was formed in liquid that consisted of a «leg» featuring different geometrical shape, a cavity and a gas-liquid layer over the bath surface at all considered Ar values. The most peculiar features of blowing zone formation, flame configuration and its structure depending on blow injection configuration and Ar values were found out. It was detected that ejected liquid prevails in the cavity structure at intensive blowing through the lance center and ring gap, and its content increases as gas flow rate rises in the shell, and the «leg» near the nozzle exit consists of the gas phase. An assumption was made that the presence of additional sulfide melt amount in the oxidative jet provides more complete magnetite destruction in the bath volume and protective skull formation in close proximity to the nozzle. Sizes of most indicative geometrical areas of flame were quantified, and they demonstrated periodical and extreme jet spread behavior in liquid. Empirical equations were obtained that describe the relation between maximum longitudinal and transverse «leg» sizes at dynamical conditions of blow injection into the shell (Ar_shell) and central tube (Ar_center) for two value ranges Ar_shell ≥ Ar_center and Ar_shell ≤ Ar_center. It was found that blow injection into the shell increases «leg» extension velocity on the nozzle exit up to 137 mm/s. The dependence of average splash lift height (H_avg, m) above the calm bath surface was defined, which is H_avg = 0.027(Ar_shell + Ar_center) ^0.27 within 25 ≥ Ar_shell ≥ 5 and 60 ≥ Ar_center ≥ 12 ranges. Schlichting equation was used to calculate the value of maximum offset from the nozzle surface where the joint axial movement of ring and round jets in liquid is maintained with equal velocities. It is assumed that the protective effect of the bottom lance with the shell appears in the lance belt area over a distance of 7–10 cm from the nozzle exit. It was noted that the cavity after separation from the nozzle moves down vertically, and the countercurrent liquid flow bounding on the cavity front moves in an opposite direction slipping the phase interface with comparable velocity. Due to more intensive changes in the interaction zone transverse size in the nozzle area and noticeable lateral liquid movement it was recommended to take corrective actions to decrease the erosive effect of melt in the Pobeda furnace lance belt at the initial jet development area. 

Pilot plant tests were carried out for the technology for chloride sublimation of lithium from petalite ore with concurrent cement clinker production. Main technical and economic indicators of lithium carbonate production were determined. Chloride sublimation roasting allows combining ore roasting and lithium sublimation with the process of Portland cement clinker production (roasting). Thus, it becomes possible to distribute energy expenditure for high-temperature firing over a much larger volume of products – clinker and lithium salts. Lithium recovered in the form of lithium chloride vapors is captured by an aqueous absorption solution, which has a much smaller volume compared to the volumes of leaching solutions in lime, sulfuric acid or autoclave alkaline technologies. Correspondingly, the flows of processed solutions are reduced, which significantly saves reagents and energy during their processing and significantly reduces the capital costs of tank equipment. Due to the high content of aluminum and silicon oxides in lithium aluminosilicate ores, it is possible to use them in the production of cement clinker instead of the clay component of the charge.

The positron emission tomography (PET) detector uses scintillator crystals to provide high image quality. Cerium-activated lutetium orthosilicates are promising crystals for PET detectors. The optical properties of resulting scintillator crystals directly depend on the impurity composition of starting materials, so they are subject to considerably stringent requirements to the basic substance content: Lu₂O₃ – 99.999 wt.%, CeO₂ – 99.99 wt.%. A starting material used for obtaining lutetium oxide of the required purity was its concentrate with a basic substance content of 99.1 wt.% with REM carbonates containing up to 54 % cerium used to obtain cerium oxide. The paper presents process flow diagrams for obtaining high-purity Lu₂O₃ and CeO₂ based on a combination of extraction and ion exchange methods. Extraction purification of lutetium and cerium from accompanying rare-earth impurities was carried out using Aliquat 336 and tri-n-butyl phosphate, respectively. Main operating modes of extraction cascades were calculated. The total number of stages was 17 for lutetium purification, and 20 for cerium purification. The purification technology for lutetium and cerium oxides consists in combining purification methods and varying cycles depending on the content of impurities. In this regard, it is necessary to control the quality of resulting substances practically after each stage. The chemical purity of technology products was subjected to analytical control by mass spectrometry with inductively coupled plasma and a spark excitation source.

Friction stir processing (FSP) is an advanced technology for altering the surface microstructure of metals and alloys to improve mechanical and performance properties. Previous research on titanium alloy processing showed that varying the FSP process parameters (such as rotational speed, movement speed and tool contact force) significantly affects the Ti–6Al–4V microstructure evolution and mechanical properties. However, the effect of multipass FSP on the Ti–6Al–4V alloy was not studied. Therefore, this paper studies the effect of four-pass FSP of the Ti–6Al–4V titanium alloy on the microstructure evolution, mechanical properties and wear resistance of this alloy. Microstructure analysis showed that the stirring zone forms heterogeneous microstructure with dynamically recrystallized equiaxed α grains, β grains and β areas with α phase of needle and laminar type, which is associated with the stirring zone temperature gradient during FSP. It was found that an increase in the number of FSP passes up to 3 times improves the ultimate tensile strength (up to 1173 MPa) and wear resistance (by 33 %). The improved ultimate tensile strength of samples after 3 FSP passes is caused by grain size reduction in the stirring zone by 88 % compared to the initial Ti–6Al–4V alloy. It was shown that after 4 FSP passes the grain size increases and the ultimate tensile strength decreases to 686 MPa in the stirring zone, which is associated with large defects formed along the contour of metal flows. At the same time the Ti–6Al–4V wear resistance after 4 FSP passes increases by 39 % compared to the raw material.

The boiling point method (isothermal version) was used to determine the partial pressure of saturated lead vapor over lead-tin solutions with the following lead content (the rest is tin), wt.%: 96.43, 93.02, 89.55, 80.73, 64.18, and 43.80 (93.93, 88.42, 83.08, 70.59, 50.65, and 30.87 at.%, respectively). The partial pressures of tin were calculated by the numerical integration of the Duhem–Margules equation using the auxiliary function proposed by Darken. The tin and lead partial pressure values over their melts were approximated by temperatureconcentration dependences. The total determination error was calculated as a sum of independent measurement errors: temperature, mass, pressure, approximation of experimental data, equal to 7.78 %. Based on the values of saturated lead and tin vapor partial pressures, the boundaries of liquid and vapor coexistence fields in the tin-lead system in a primary vacuum of 100 and 1 Pa were calculated and specified: boiling temperature – as a temperature at which the sum of metal partial pressures is equal to 100 and 1 Pa, vapor composition – as the ratio of metal vapor partial pressures at this temperature. It was found that the reason for the increased content of tin in lead condensate during the distillation of alloys with a lead content of less than 5 at.% (8.41 wt.%) and tin accumulation in the distillation residue is partial pressure values of tin vapor comparable to that of lead. Tin accumulation in the distillation residue should not exceed a concentration of ~ 50 wt.% during the distillation separation of lead-tin melts by lead evaporation in a real process under non-equilibrium conditions. If the specified concentration is exceeded, the condensate obtained will require repeating the evaporation-condensation process.

A comparative study of VT-1.0 titanium boriding, carboboronizing and borosiliconizing methods was carried out in order to increase wear resistance in aggressive environments at elevated temperatures. The microstructure of diffusion coatings was investigated, their thickness and microhardness were determined. Diffusion saturation of 10×10×25 mm VT-1.0 titanium samples was carried out from saturating coatings based on boron carbide. Process temperature of 950 °C, and saturation time of 1.5 h were used as saturation conditions. At the end of high-temperature exposure, samples were removed from the furnace and cooled in air to room temperature, cleaned from saturating coatings with wooden spatulas, and boiled in the soap and soda solution for 1 h. A continuous diffusion layer 80–100 μm thick forms on the titanium surface. The borosiliconized diffusion layer obtained by titanium saturation from the mixture of 45%B₄C–5%Na₂B₄O₇–22%Si–5%NaF–3%NaCl– 20%CrB₂ has a higher microhardness: 1520 HV_0.1 versus 1280 HV_0.1 for carboboride one and 1120 HV_0.1 for boride one. In this case, boride and carboboride coatings, obtained, respectively, by saturation from 45%B₄C–5%Na₂B₄O₇–5%NaF–25%Al₂O₃–20%CrB₂ and 70%B₄C– 5%Na₂B₄O₇–5%NaF–20%CrB₂ coatings have a pronounced zonal structure. The upper zone of these coatings having high microhardness also features high brittleness indicators, which makes it impossible to accurately measure microhardness distribution due to chipping and cracking at microhardness measurement points. The qualitative composition of coatings on titanium was studied by X-ray diffraction using the DRON-6 X-ray diffractometer in filtered CuK_α radiation (λ = 1.5418 Å) in the angle range of 2θ = 20÷80°. The diffusion coating exhibits reflections of titanium carbide, chromium and titanium borides, and a certain amount of the Cr₂Ti intermetallic compound. Boride phases of chromium and titanium refer to high boron phases with high specific boron content: TiB, CrB, Ti₂B₅, Ti₃B₄ и Cr₂B₃.

This study focuses on the development of new Al–Cu–Mn alloys with enhanced strength and heat resistance achieved without hightemperature exposure. Seven alloys were considered including ones containing permanent Mn content of 2 % and variable Cu content of 0– 4 %. It was found that ~ 2 % Mn is completely dissolved in the solid solution of aluminum, while copper in the cast structure is distributed between the solid solution of aluminum and Al₂Cu eutectic phase inclusions. It was experimentally established that when the copper content is 2 and 3 %, the solid solution of aluminum contains approximately the same amount of copper – up to 1.5 %. The deformation plasticity of experimental alloys in the cold rolling mode with the reduction rate of 80 and 95 % was investigated. It was shown that no preliminary treatment is required for alloys containing up to 3 % Cu as they feature high rolling workability. Then, the effect of heat treatment in the annealing temperature range of 200–600 °C on the structural and phase parameters of the alloys was studied. Alloy hardening in the process of multistage annealing by means of hardness measurement was analyzed. The data obtained allowed us to determine the influence of copper and analyze the thermal stability of model alloys. Tensile tests of cold rolled sheets with a thickness of 0.5 mm with a reduction rate of 95 % of alloys containing 2 and 3 % copper showed high performance. Particularly, the alloy containing 3 % Cu has strength compatible with that of the 1201 alloy in the T6 state.