The acoustic generator technology was used to arrange in-furnace dust deposition in the Vanyukov furnace, OJSC SUMZ (Revda, Russia). The generator design included a nozzle tube, an air nozzle, a resonator and a focusing surface. The total acoustic power of the acoustic field and the optimum number and location of the acoustic generators were determined based on the surface area of the furnace molten pool and the recommended values of specific acoustic power for in-furnace dust deposition. To create an acoustic field in the Vanyukov’s furnace for melting the sulfide copper zinc-containing raw material and depleting the liquid converter slag, four acoustic generators were installed in the end wall through the inspection window: two on the uptake side and two on the charge material loading side. In total, six pilot modes of in-furnace dust deposition system testing at different operation settings of acoustic generators were implemented with one basic mode to compare performance. The duration of test periods ranged from 5 to 18 days, and the total operation time of the unit using acoustic generators was 68 days. It should be noted that the presence of an acoustic field in the furnace body at any operation settings of generators in one way or another helped to reduce the concentration of dust particles downstream the chain of gas purifiers (at the commodity point). According to test data, it was found that the minimum total acoustic power of the acoustic field, which reduces the dust concentration due to the coagulation of dust particles within the furnace space, is 800 W.

 

The article presents study results of soda and low-titanium slag baking, where the slag is produced during processing of titanium magnetite concentrate. The purpose of baking is to change the mineralogical composition of Ti-containing phases and obtain a product suitable for chemical separation of titanium dioxide from impurities. The X-ray phase analysis revealed that the obtained titanium slag belonged to the spinel-anosovit type. The article studies the factors influencing the baking process: the slag to soda mass ratio, the process duration, the temperature and the size of slag particles. The thermal analysis of the slag and soda baking process revealed that the optimum process temperature was 900°C. This temperature ensured formation of sodium titanates and a cake of sufficient porosity. The article demonstrates that effective decomposition pro cess requires a pretreatment of titanium slag by fine grinding. It was found that grinding of titanium slag particles to 40 μm contributes to more complete decomposition of the anosovite and formation of sodium titanates. It was found that during titanium slag and soda baking at the slag to soda mass ratio of 1 : 1,05, decomposition of anosovite occurred, and virtually all titanium was bound to sodium titanates. Optimal process conditions were determined as follows: slag to soda mass ratio – 1 : 1,05, baking temperature – 900 ° C, duration – 60 minutes and slag particle size – 40 μm. During baking, the titanium-containing slag phases were converted into Na₂TiO₃ and Na₈Ti₅O₁₄. The presence of a significant amount of silicon dioxide and the sodium-magnesium silicate phase was observed in the cake. The electron microprobe analysis of the cake showed that impurity elements were adsorbed on the particles of formed Na₂TiO₃.

When cleaned from impurities lead is treated with zinc reacting with precious metals to form refractory intermetallics that are not soluble in the base metal – a silver crust (SС). The laboratory studies for processing of SС containing, %: 78–80 Pb; 15–17 Zn; 3–5 Ag; 0,0001–0,002 Au by vacuum distillation (t = 800÷1200 °C, Р = 10^–1÷10^–3 mm Hg; τ = 2÷42 h) to separate zinc, lead and precious metals. At t ~ 800 °C, Р = 10–1 mm Hg, zinc condensate was obtained containing, %: 99,85 Zn, 0,14 Pb. At t ~1000 °C, Р = 9·10^–3 mm Hg, zinc-lead concentrate (15,7 Zn; 83,6 Pb; 0,02 Ag), lead concentrate (86–87 Pb; 0,4–2,8 Zn; 0,04–0,12 Ag), silver concentrate (50–67 Ag; 0,1–5,3 Pb, 0,04–0,2 Zn). At t ~1200 °C, Р = 6,5·10^–3 mm Hg, lead concentrate (91–97 Pb, 0,6–1,7 Zn; 0,01–1,2 Ag) and silver concentrate (92 Ag, 1,4 Pb, 0,1 Zn) were obtained. It is shown that the degree of vacuum in the system increased up to over 0,1 mm Hg causes no significant changes in the indicators of silver crust vacuum distillation. Quantitative sublimation of zinc takes place at a temperature not exceeding 800 °C for 1 h. The end of the process is indicated by a pressure surge in the system up to Р = 1,5÷2,0 mm Hg. SC liquation producing crude lead (~42 % of the original quantity of Pb) and liquated silver crust (LSC) containing, %: 76,39 Pb; 16,56 Zn; 6,254 Ag, is possible for 2 h in an inert gas atmosphere (Ar) at t = 700±10 °C without vacuum. Temperature of lead draining is 380±10 °C. Quantitative sublimation of lead and zinc from LSC is optimal (>99 %) at t £ 1000 °C for 12 h, At the same time ~20 % silver of the original quantity in SC is extracted from the composition. Velocities of zinc (800 °C), lead and silver (1000 °C) sublimation are identified (calculation/experience) and equal to v·10^–4 g/(cm²·s): 19,13/24,05 Zn; 6,25/8,6 Pb; 0,0068/0,0065 Ag. These v values can be used to design the equipment for vacuum distillation of silver crust.

 

The study covers the method of additional cleaning of ammonium perrhenate desorbates from molybdenum through sorption recovery of rhenium from Mo-containing solutions with Purolite A170 and A172 weak base anion exchange resins. The dependence of Re(VII) and Mo(VI) sorption using these resins on solution pH was studied under static conditions with the 1 M (NH₄)₂SO₄ solution. It was found that the pH range at which the resins retain the ability of Re(VII) sorption extends to a weak-alkaline area. A significant decrease in Re(VII) adsorption begins when pH exceeds 7,5 Mo(VI) capacity of the resins decreases significantly when solution pH exceeds 5,0, and both anion exchange resins practically stop molybdenum sorption at above pH ~ 7,0. Reduction of Mo(VI) content in rhenium desorbates obtained in sorption recovery of Re(VII) from Mo-containing solutions with weak base anion exchange resins can be achieved as follows. First, major quantity of adsorbed Mo(VI) is desorbed from the loaded resin by ammonium sulfate solution when stirring the mixture and keeping pH constant in the 7,0–7,5 range by dosing the ammonia solution. Then the resin is separated from the Mo(VI)-containing ammonia solution, washed with water, and Re(VII) is desorbed by the ammonia solution in dynamic conditions. The proposed method was verified with anion exchangers loaded in sorption from the model solution with the following composition, g/L: 98 H₂SO₄, 4 Mo(VI), 0,5 Re(VII). It was shown that resin treatment with the ammonium sulfate solution removes at least 90 % of adsorbed molybdenum. A ratio of Re(VII) to Mo(VI) concentrations in ammonium perrhenate desorbates increases by 11 times with Purolite A170 resin, and by 20 times with Purolite A172 resin compared to the results obtained without an additional Mo(VI) washing. Re(VII) losses (reversible) with the Mo-containing desorbate are below 5,2 % of the adsorbed Re(VII) amount.

 

 

The development of modern foundry is characterized by a constant increase of requirements to the quality of the casting, the rational use of material resources, the search for new technical and technological solutions to ensure resource conservation along with obtaining the desired properties of castings. At the same time questions to identify and study the impact of the laws of temperature and time parameters of melting and pouring into the mold of aluminum alloys during lost foam casting on integrity, mechanical and quality parameters of thin-walled castings are poorly understood and difficult to implement, especially in view of resource saving measures. This article examines the influence of casting process parameters on strength, integrity and content of nonmetallic inclusions in AK7 alloy castings of the gas analyzer housing cover obtained by lost-foam casting. The dataset obtained on the basis of experimental research was subjected to statistical analysis. Statistical models allowed us to obtain the effect of time of melt holding and the content of recycled materials in the charge on strength and integrity of the specified castings. The effect of the time of AK7 melt holding at 880–890 °С on the content of nonmetallic inclusions in the castings was studied, and it was shown that the holding time variation allows controlling the nonmetallics content. This reduces melt microinhomogeneity and provides more castings with the minimum content of nonmetallic inclusions.

 

A comparative study was carried out to determine the effect of AlZr4, AlZr10 and AlSc2 modifying master-alloys and magnetic-pulse treatment (MPT) on the density (in liquid and solid state), electrical conductivity (in solid state) and macrostructure of AMg5 and AMg6 alloys. Molten master alloys were poured into special devices to ensure a cooling rate of ~10², ~10³ and ~10⁶ °C/s during crystallization. Master alloys were introduced into the melts at the rate of 0.01% per modifier element. It is shown that melt modification with nucleating additives contributes to higher alloy density in liquid and solid states. The electrical conductivity of the alloys with AlZr4 and AlZr10 master alloys added is lower. The AlSc2 master alloy introduction causes an increase in the electrical conductivity of AMg5 and AMg6 alloys. This effect is observed for the first time and requires additional research. It is found that the AlSc2 master alloy obtained by crystallization in a water-cooled roller mold has the greatest influence on the physical properties of alloys in comparison with AlZr4 and AlZr10 master alloys. It also provides maximum macrograin refinement. Magnetic-pulse treatment (MPT) of melts following the axial scheme of impact contributes to higher density of alloys in liquid and solid states similar to the introduction of modifying master alloys. Electrical conductivity increases after MPT as with the AlSc2 master alloy added to melts. Alloy macrograin refinement at magnetic-pulse treatment is comparable with the addition of the AlZr4 modifying master alloy. The comparative studies allow for the conclusion that magnetic-pulse treatment can be attributed to physical modification methods. The methods of density and electrical conductivity determination can be used for express evaluation of the studied effects for their modifying effectiveness.

 

 

In order to determine the thermal gradient in a single crystal ingots obtained using the directional solidification method on the UVNS-6 apparatus (Russian Scientific Research Institute of Aviation Materials, Moscow), the single crystal ingots of nickel-based superalloy VJM3 were made. The ingots were made using the liquid metal cooling (LMC) directional solidification method (DS) and without it (Bridgman–Stockbarger technique). The liquid Sn was used for a liquid metal cooling technique. To record the temperature during the ingots obtaining process we use a thermocouple placed on the ceramic mold surface. The directional solidification process of the nickel-based superalloy VJM3 ingots on the UVNS-6 apparatus was simulated using the ProCast software. The thermal properties of the VJM3 alloy, ceramic mold and the DS apparatus parts and the boundary conditions (interface heat transfer coefficient) were  found in the literature. There is a good agreement between the calculated and experimental values of the temperature distribution in a mold using the LMC and the Bridgman–Stockbarger technique. A simulation of the directional solidification in the ProCast software is suitable for predicting the thermal gradient on a solidification profile location, and the mushy zone width (a site of the dendritic structure formation). The calculated thermal gradient value in the ingot obtained using the Bridgman–Stockbarger technique is 36 °С/cm. The thermal gradient using the LMC method is 204 °С/cm, is six time higher, than if using the Bridgman–Stockbarger technique. Used thermal properties and boundary conditions can be applied for simulation of Ni-based superalloys blades casting process.

 

 

The paper provides a method to obtain hemisphere part in a die where the part surface is formed by the counter die. This is due to the tool design with a steel elastic element placed around the punch. Such process scheme allows for two different processes combined in one tool: drawing and calibration. Drawing sphere-like parts requires calibration since the part has a large area that is not in contact with the punch and die where the part looses stability and starts to buckle. The elastic element made of spring steel and placed around the hard punch calibrates part at the final drawing stage. The paper provides a forming scheme to obtain hemisphere parts with a relative thickness S′ = S/D0·100 % = 1,5÷0,15. Process parameters are evaluated using the engineering method. Geometrical parameters are calculated for the Steel 1060 elastic element for hemisphere part drawing of aluminum alloy 5056 with a thickness of 0,5 to 10 mm. The size of a gap between the punch and elastic element is determined. Maximum stresses occurring in the elastic element when forming are calculated. It is found that the elastic element has no plastic deformation. It is proposed to use the elastic element to produce parts with accurate geometrical dimensions and compensate elastic restitution.

 

The study covers technology features of making pressed items of non-ferrous metals by Conform continuous forming. The analysis of pressing equipment designs identified a disadvantage typical for many Conform units – the lack of connection between the system for securing the fixed part of the split container (shoe) and the impeller shaft. Therefore, it is impossible to ensure a controlled gap between the shoe and the groove bottom during the operation, which results in unstable bar stock feeding to the die. The paper aimed at the development of a new shoe attachment system to ensure a steady flow of continuous metal extrusion process. This provides for forming a rigid and strong connection between the shoe and the impeller shaft using the system of levers and rods. An upgraded die assembly was proposed to solve this problem. The drive components and working parts of the pilot Conform unit were designed based on power calculations made for extrusion of aluminum and copper alloys using the formulas provided in the technical literature. The obtained results were used for strength calculations of die assembly parts following the known methods. The practical use of the design proposed in the paper will provide new opportunities to make pressed steel items of non-ferrous metals with a consistently high level of properties.

 

Research infrastructures play a vital role in advanced scientific research. At the same time they are an important element of innovative development of the Russian metallurgical industry. Its modernization and improved competitiveness on global markets can be facilitated by the opportunities of the open access both to Russian and European research infrastructures. The paper describes the types and rules of access. Transnational access to European research infrastructures is possible only on a competitive basis where up to 20% of the test time is provided to user teams from Russia and some other countries. Virtual access ensures free of charge access to e-Infrastructure, namely to powerful computers, networks and databanks in various fields. In addition, the paper describes information resources providing all necessary data about the main European research infrastructures.