Nonferrous ore concentration
Bocharov V.A., Ignatkina V.A., Khachatryan L.S. The main principles of choosing and joint application of selective collectors and depressors used in flotation of sulfide minerals with close physicalchemical properties
The mechanisms of interaction of different sulfide ore floatation collector and depressor classes have been investigated. Optimal conditions have been found for selective floatation of sulfide mineral complexes with application of dithiophosphate based sulfhydril collectors and CMC (sodium celluloseglycolic salt) modified by heavy metal salts as selective depressor. Combinations and ratios of collector and depressor were determined whereby active flotation of some sulfide minerals and depression of other ones were determined. The inprocess tests of different ore kinds verified the results of the theoretical experiments.
Extractive metallurgy of nonferrous metals
Kokoeva N.B., Svistunov N.V., Alkatseva V.M. Investigations of complex zinc cake processing
Zinc cake processing studies have been carried out aiming at the zinc, copper, and iron transition from ferrites into solution and noble metal concentration in the zinccontaining silicate product. Zinc cakes were subjected to sulphatization with oleum followed by leaching with sulfuric acid solution. To study the affect of sulfuric acid concentration, duration, and temperature on the sinter leaching process, multifactorial experiment after Box’s plan has been carried out with obtaining models of the following dependence on the said factors of zinc, copper, and iron extraction into the solution. A possibility of full Zn, Fe, and Cu extraction into the solution was shown. As optimal, the following leaching conditions were suggested: H2SO4 concentration in leaching and washing solution is 8,33 g/l, leaching duration is 2 hours, temperature is 75 °C.
Extractive metallurgy of less-common and precious metals
Fleitlikh I.Yu., Pashkov G.L., Mikhnev A.D., Grigorieva N.A., Nikiforova L.K. Extraction process of nickel sulfate solution purification from impurities using dialkyl phosphinic acid
The data of laboratory studies related to purification of nickel sulfate solutions from impurities (Fe, Cu, Zn, Mg, Ca) are given. Cyanex 272 [di(2,4,4trimethylpentane)phosphinic acid] is shown to be the most effective extractant: raffinates of the following composition (in g/l) Ni 120ё130, Cu, Zn and Fe Ј 2·10–3 each, Mg Ј 0,1 and Са 0,2ё0,3 may be obtained from solution (after iron removal) containing (g/l) Ni 120ё130, Сu 0,8ё1,0, Zn 3,0ё4,0, Mg 1,5ё2,0, Ca 0,4ё0,8, Fe 0,01ё0,02 for two stages of extraction by Cyanex 272 nickel form. Purification of raffinates from organic impurities (extractant, dilutant) after extraction is performed by sorption over DAK active carbon. Reextraction of metals and accordingly reactivation of extractant are easily performed by solutions of mineral acids (H2SO4 and HNO3). Nickel removal out of the solution is і 99,8 % in the extractive reduction.
Naumov A.V. A review of the world market of rareearth metals
The current state of the world market of rareearth metals is reviewed on the basis of publications of the recent years. Periods of its development are shown and the prospects are considered.
Casting production
Kondrashov E.N., Maksimov A.Yu., Konovalov L.V. Quasistationary characteristics of VT31 alloy solidification during vacuumarc remelting
The article gives calculations of liquid bath depth, time of local solidification, and temperature gradient in the axial zone of a vacuumarc remelted ingot of VT31 titanium alloy (Ti–6,5Al–2,5Mo–1,5Cr–0,5Fe–0,3Si) being consistent with the quasiequilibrium conditions. The calculations have been carried out for ingots of diameter D = 400, 800 and 1200 mm within a range of mass melting rates = 0,5ё12,0, 0,5ё35,0 and 1,5ё30,0 kg/min respectively. The liquid bath depth (H, mm) is found to increase linearly when grows and is not dependent on D under the conditions considered, therefore it may be given as a unified dependence: Н = 66,63 + 71,91. The dependent time of local solidification is shown to have a minimum related to different physical processes causing the kinetics of the solidification front at little and great melting rates. In relative units corresponding to the minimum, the dependences are identical for all ingot diameters analyzed. Furthermore, based on the data of autoradiographic studies of VT31 alloy solidification at the vacuumarc remelting conditions, critical values of the temperature gradient (G) and the solidification front movement rate (v) along the ingot axis determining the transition from the columnar structure to equiaxial one have been found. In terms of the results, v(G) diagrams have been plotted, which prove to be very useful for development of remelting conditions excluding any type of segregation defects. It was found that at the given ingot diameter the v(G) dependence is decreasing and at the given temperature gradient the front movement rate decreases when D grows, indicating this in favor of D increase in melting high alloy ingots.
Yudina I.V., Gerasimov S.P., Pikunov M.V. Production of copperchromium alloys for cast electrodes of contact welding
A possibility of producing BrKh1 copperchromium bronze under the conditions of open melting as well as cast electrodes of the alloy is considered. It was found that the use of Cu–10%Cr foundry alloy prepared by mechanical alloying allow obtaining alloys of prescribed composition without significant losses and additional operations under the conditions of open melting. Parameters of the properties of cast and heat treated alloys are no lower as compared with wrought alloys of the same composition. The effect of phosphorus used for deoxidation of melt on the microstructure and properties of cast BrKh1 bronze was determined.
Metal forming
Parshin S.V. Metal deformability in forming profiled pipes from sheet with application of compression in gauge
A procedure of plasticity margin (wS) calculation in forming profiled pipes from sheet based on the Kolmogorov–Bogatov model has been developed. Metal stress condition factor was determined and numerical analysis of plasticity margin calculation in such processes with superimposition of tangential stress or tension in deformation location was carried out. Superimposition of tension in gauge in forming pipes results in increase of metal plasticity.
Yenikeev F.U. Mathematical modeling of pressure shaping of commercial titanium alloys in superplastic state
The boundary value problem in the mechanics of superplastic flow is formulated with the aim to be used in developing mathematical models of commercial titanium alloy superplastic metal working. The approach suggested includes constitutive equations of the creep theory with internal variables describing the structural evolution during superplastic forming of commercial sheet titanium alloy VT6ts (Ti–6%Al–4%V) in the superplastic condition. The material constants are determined from the results of technological experiments. The ANSYS software package is used to solve the boundary value problem stated. The calculations are carried out by using different finite element meshes and fastening conditions. The results obtained are compared with the experimental data as well as with the engineering computations. The conclusion is made that the engineering approaches under analysis can be used in practice when the loading conditions chosen correspond to the optimal conditions of temperature and speed superplastic flow in the volume of the material to be deformed.
Materials science and heat treatment
Trykov Yu.P., Slautin O.V., Arisova V.N., Shmorgun V.G., Ponomaryova I.А. The effect of process factors on the kinetics of diffusion in copperaluminum composite
The purpose of this work was to study the effect of heat treatment schedules, furnace atmosphere, and protective technological coatings of different composition on formation of phase composition of diffusion layers in the welding zones of layered intermetallics composite of the CuAl system produced by the aggregate technology.
Surface engineering. Multifunctional films. Corrosion and metal protection
Pogrelyuk I.N., Yas’kiv O.I. Anode behavior of titanium alloys with nitride coatings in sulfate acid solution
Corrosion behavior of VT10, OT4, and VT14 titanium alloys with nitride coatings formed with and without graphite powder in technically pure nitrogen of rarefied (1 Pa) and atmospheric pressure at t = 750ё1000°C for t = 5ё20 h has been studied. It was found that coatings are characterized by high protective properties. Anodic behavior of nitride coatings depends on correlation of nitride phases in coating, their stoichiometry, surface relief and defectiveness, which are determined by the conditions of coating formation (temperature, duration, nitrogen pressure and other medium characteristics). It was shown that treatment in twocomponent medium (molecular nitrogen and graphite powder) improves the electrochemical characteristics of nitride coatings without influence on their structural and phase state.
Process control and automation
Maltsev G.I., Vershinin S.V., Lebed’ A.B., Naboichenko S.S. Creation of mathematical model of sulfide sublimating of germanium from middlings
An adequate mathematical model has been constructed of the effect of charge composition on the degree of pyrometallurgical germanium sublimate based on empirical dependences of Y variable, germanium sublimate degree (%) in the sulfide melting conditions (t = 1350 °С, t = 1 h), on the parameters characterizing the content in the charge (%): Х1·10–2 – basicity {([CaO] + [MgO])/ [SiO2]}; Х2·10–3 – germanium; Х3 – slagforming components (S[CaO], [MgO], [SiO2]); Х4 – carbon; Х5 – sulfur, by the use of computer mathematics with application of standard “Excel”, “Mathcad”, “Maple” software packages.
Salikhov Z.G., Shapirovsky M.R., Volgin P.V. Synthesis of mathematical model of nickel tetracarbonyl decomposition process
A possibility of system implementation for automated control of nickel tetracarbonyl decomposition process is analyzed. The correlation analysis of process parameters has been carried out taking their lag as regard to quality measures into account. Models of the first and second orders connecting the finished product quality measures with the most coupled process parameters are developed and analyzed. A possibility of their application in the nickel tetracarbonyl decomposition process automatic control system is shown.
Salikhov Z.G., Shapirovsky M.R., Volgin P.V. Synthesis of algorithms of nickel tetracarbonyl decomposition control process
An automatic control system has been created for the nickel tetracarbonyl decomposition process. An analysis of confidence intervals of first and secondorder models created is performed. The model allowing us to compensate the effect of perturbing factors as well as the mutual effect of control action on the adjacent zones is described. Based on the algorithm given, creation of an adaptive automatic control system for nickel tetracarbonyl decomposition is possible.
