The paper considers the results obtained in the study of the prospective gold-silver complex deposit at the Eriksky ore cluster (Khabarovsk Territory) with refractory pofycomponent ores. Energy dispersive, atomic emission, grain size and dispersive analysis of rock samples were carried out. Samples contained microelements of a wide range including gold, silver, bismuth, cobalt, chromium, manganese, molybdenum, nickel, lead, vanadium, tungsten, zinc, copper, etc. It was found that pofycomponent and dispersed composition of mineral raw materials at the deposit defines it as a complex object to extract valuable components. It was proposed to use systems based on methods that reduce consumption of reagents to address the issue of precious metal extraction with more environmentally and technologically efficient tools. It is achieved by creating conditions for a sustainable process of preparation for leaching of mineral components containing gold and platinum through destruction of the mineral component of refractory polycomponent ores by increasing micro disintegration fields using ultrasound. Providing sustainability of mineral crystal lattice destruction by regrinding the solid phase formed during cavitation is a fundamental factor when preparing for the extraction of microparticles of valuable components.

The paper provides a review of the literature on the interaction of magnesium production salt melts with atmospheric air. The method for measuring the mass of reaction products of the molten salt with air is described. The results of investigation of hydrogen chloride and chlorine emission intensity by salt melts of MgCl₂-KCl-NaCl, MgCl₂-KCl-NaCl-BaCl₂, MgCl₂—KCl—NaCl—CaCl₂ systems, as well as the intensity of HCl + HBr and Cl₂ + Br₂ gas emission by MgCl₂—KCl—NaCl—NaBr system salt melts are presented. Thermodynamic analysis of reactions of interaction of magnesium salt melts with atmospheric air is carried out. It is determined that magnesium chloride in salt melt interacts with atmospheric air most intensively with the release of chlorine and hydrogen chloride. Specific rates of halogen-containing gases formation per unit surface area of the MgCl₂-KCl-NaCl, Mga₂-KCl-NaCl-BaCl₂, MgCl₂-KCl-NaCl-CaCl₂, MgCl₂-KCl-NaCl-NaBr systems are measured. The influence of calcium chloride, sodium bromide and magnesium fluoride on the intensity of halogen-containing gases emission by the surface of salt melts is studied. It is found that the addition of magnesium fluoride in the composition of chloride melts reduces the intensity of chlorine and hydrogen chloride emission.

The article presents the results of a numerical study of temperature-time dependences in continuous combined casting and pressing of the AK12 experimental aluminum alloy, which has a different overheating temperature, in the time interval from start-up to the moment of the unit reaching the stationary thermal regime. Calculations are carried out on the basis of a three-dimensional computer model of complex heat transfer in the unit of a new design equipped with a horizontal carousel crystallizer. Theoretical studies are conducted to determine the influence of superheating of poured aluminum melt on the processes of unsteady heat transfer. The influence of the nature of heat transfer in the transient thermal regime on the temperature field of the solidifying melt at different distances from the pour point is determined. It is shown that as the crystallizer heats up in the transition process, the asymmetry of the temperature field in the control section of metal increases near the pressing tool with the shift of the maximum temperature region to the crystallizer contac surface. It is found that the transition process duration when starting the unit in a cold state until it reaches a stationary thermal regime depends on the temperature of poured melt. The maximum limit of the overheating value is determined, above which poured metal, when implementing the technology of continuous combined casting and pressing, aluminum melt does not solidify in the crystallizer and forced cooling of unit elements must be arranged. The influence of melt overheating on the pattern of the temperature field along the crystallizer cross section over the entire period of the transient thermal process is estimated. Design measures to ensure rational temperature conditions of bearings during the unit operation are determined.

The article considers the compaction of Al-B-W system powder in a copper shell. Such material is supposed to be used, for example, to produce grinding tool components or radiation protection elements. For this purpose, it is necessary to obtain both short and long-length semi-finished products which required the development and testing of various technological schemes (technologies) based on the use of static, dynamic loads and their combinations. Analysis of the results of the experiments showed reality and the possibility of implementing the proposed schemes to obtain tubular semi-finished products of different sizes. The whole chain of their manufacturing from powder production to compaction and sintering is considered. Metallographic studies conducted to assess the quality of sintered powder composition demonstrated almost full absence of pores. The technology is developed to ensure making new products, including long-length ones, from powder composition.

The article focuses on the actual problem of creating economically alloyed antifriction aluminum alloys doped with low-melting metals. It was found in earlier experiments that an alloy containing about 5 % Si, 4% Cu and 6 % Sn (wt.%) has a balanced complex of technological and physicomechanical properties. Due to the high cost of tin, this paper considers the possibility of reducing its concentration to 4 %, and its partial replacement by other low-melting metals, such as bismuth and lead. Thermodynamic calculations (in the Thermo-Calc program) including the construction of polythermal and isothermal sections are used to study the joint and separate influence ofthese elements on the phase composition of the Al—5%Si—4%Cu—4%Sn alloy. It is shown that the addition of lead and bismuth leads to the appearance of an extensive area of fluid separation, and therefore their total concentration should not exceed 1—2 %. The phase composition and microstructure ofthe Al—5%Si—4%Cu—4%Sn—0,5%Pb—0,5%Bi alloy were studied using scanning electron microscopy and micro X-ray spectral analysis. It was found that in the cast state, low-melting metals are evenly distributed in the structure of the alloy, and in terms of the combination of properties, the experimental aluminum alloys surpass the BrO4Z4S17 antifriction bronze. Heat treatment mode T6 leads to a significant increase in the hardness of the experimental alloy. However, in the process of heating for quenching at 500 °C, local fusion of the low-melting component occurs, which leads to deterioration of the microstructure upon re-crystallization and, as a result, causes alloy embrittlement.

The paper presents an investigation of the structure and mechanical properties of A356.0 and A413.1 cast aluminum alloys subjected to a pulsed magnetic field of different saturation during crystallization. It was established during experiments that samples contain in their composition two phases that crystallize at certain temperature intervals and do not change even when magnetic field is applied to the crystallizing melt. A temperature gradient was found between the mold wall and the outer wall of the crucible for both alloys, which varies between <14,3 and 16,0 °C/mm, as well as the crystallization time of each phase. Using thermophysical approaches, a linear crystallization rate was found for both alloys. It was determined that it decreases with decreasing temperature gradient, while the crystallization time of phases increases. It was found that the magnetic field changes the distribution of dendrites over the volume of A356.0 and A413.1 alloys, as well as their dimensions and orientation in the section plane. With an increase in the magnetic field induction amplitude, a finer structure is formed in the а-phase of the alloy, which uniformly fills the section plane, and this is reflected in its mechanical properties. The hardness of the investigated alloys increases with an increase in the amplitude of the pulsed magnetic field induction by approximately 8—10 % for both alloys due to the refinement of the dendritic structure and a more even distribution of а-solid solution dendrites over the volume of the crystallizing sample. In addition, the magnetic field affects the ultimate tensile strength, and practically does not change the value of relative elongation under uniaxial tension of the investigated A356.0 and A413.1 alloys.

The kinetics and mechanism of fatigue fracture of VT6 titanium alloy (composition, wt.%: 5,95 V, 5,01 Al, 89,05 Ti) in the initial (hot-rolled) coarse-grained state and after equal channel angular pressing (ECAP) in the ultrafine-grained state were studied. Blanks used for ECAP were made of the specified alloy 20 mm in diameter and 100 mm in length previously subjected to homogenization annealing. Then, quenching was carried out in water from 960 °C (1 hour), tempering at 675 °C for 4 hours, ECAP at 650 °C (Вс route, ф = 120°, n = 6 passes). The fine structure of the alloy after ECAP was studied using transmission electron microscopy at accelerating voltage 200 kV. The Time Group TH 300 hardness tester was used to determine alloy hardness. Static tension of round samples with a diameter of 5 mm was carried out on the Tinius Olsen H50KT universal test machine. Tension speed was 5 mm/min. Fatigue tests of 10 mm thick prismatic samples were carried out at 20 °C using the three-point bending test at the Instron 8802 unit. It was shown that under the same loading conditions, sample durability (the number of cycles before failure) from the alloy in the initial coarse-grained state is slightly higher than in the ultrafine-grained state. The number of cycles before fatigue crack formation, regardless of the alloy state, is at the level of 19—23 % of the total durability of samples. The straight section in kinetic diagrams of alloy fatigue fracture is approximated by the Paris equation. It was found that the rate of fatigue crack propagation in an alloy with an ultrafine-grained structure is somewhat higher than in an alloy with a coarse-grained structure. The microrelief of VT6 alloy fatigue fractures both in coarse-grained and ultrafine-grained state can be characterized as «scaly» with fatigue grooves on the surface of flakes. The region of fracture of the alloy with the ultrafine-grained structure contain a low-relief area 4—6 pm in length. The break, irrespective of the alloy state, has a pit microrelief.

The results of model studies on the possibility of reducing energy costs and carbon dioxide emissions during the Waelz processing of oxidized zinc-containing material in waelz kilns are presented. The studies were carried out using a specialized software product METSIM widely known in the world practice of metallurgical process and production modeling that allows analyzing the effect of changes in technological modes on the final results of the process. Model calculations showed that the greatest decrease in specific energy consumption and CO₂ emissions is observed when using blast air heated to 200 °C with an increase in its flow rate from 1000 to 7000 n.m³/h and concomitant decrease in atmospheric air suction. The estimated reduction in the specific costs of carbon and CO₂ emissions amounted to 30,2—35,5 %, and the total specific cost of energy carriers — 28—32 %. At the same time, blast air heating to 200 °C in the heat exchanger of the recovery boiler does not require additional energy inputs, in contrast to the use of oxygen blast with the cost of electricity for producing oxygen. Intensification of the waelz process using additional oxygen blasting (or air blast enrichment with oxygen) and heated blast air supply with concomitant decrease in air suction into the furnace from the atmosphere leads not only to a decrease in the specific consumption of the carbon energy carrier, but also to an increase in the degree of carbon utilization. The maximum estimated increase in the degree of carbon utilization was 6,2 rel.% — from 60,3 % on cold air blast without oxygen to 66,5 % on an air-oxygen blast (7000 n.m³/h of air and 185 n.m³/h of oxygen) heated up to 200 °C without atmospheric air. Maintaining optimal oxidation-reduction and thermal modes of the process requires correct regulation of the kiln draft mode taking into account atmospheric air suction in the unloading head of the kiln. Uncoordinated changes in the specific consumptions of charge, carbon, blast air and rarefaction in the dust chamber lead to a concomitant decrease in the extraction of zinc to sublimates and increase in its losses with clinker.

08.01.1937-06.04.2019