Mineral processing of nonferrous metals
Adamov E.V., Krylova L.N., Kanarsky A.V. Updating of conditions and diagrams for bacterial leaching of sulfide concentrates
The effect of chemostat battery supply diagram on bacterial leaching of sulfide concentrates has been studied. The investigations of the parameters and conditions of the process was carried out in a laboratory plant consisting of 5 working reactors of 1,5 liter in working volume each and a conditioning tank. Gold-arsenic arsenopyrite concentrate of flotation concentration containing Au, Ag, and As as well as Acidithiobacillus ferrooxidans bacterium strain adapted to it was used. Double-flow conditions of chemostat battery supply was found to rise the leaching rate to 70 % excess of critical rate of dilution in the single-flow conditions with keeping of sulfide mineral oxidation rate at the output.
Key words: bacterial leaching, bacterial oxidation, gold-arsenic concentrate, sulfide minerals, redox potential, biomass activity, pH, chemostat.
Metallurgy of nonferrous metals
Volodin V.N., Khrapunov V.E., Burabayeva N.M., Marki I.A. Phase equilibrium of liquid-vapor in decomposable thallium-zinc system
Zinc vapor pressure over liquid alloys with thallium at the temperatures above the limitedsolubility region in the liquid phase has been determined by jet and boiling point methods. The fact of chemical potential equality at constant temperature at the boundary of two-phase and homogeneous region of liquid solutions occurrence is taken as a basis of the technique for determination of thermodynamic functions in the phase separation area. Partial and integrated thermodynamic characteristics of the vapor and condensed phases are determined and presented in the form of temperature-concentration dependences. The system is characterized by the positive deviation from the ideal solution law. The boundaries of phase liquid-vapor transition in the thallium-zinc system at the atmospheric pressure and in vacuum of 100 and 10 Pa are determined by extrapolating the dependences of vapor pressure of the components onto the hightemperature region. The region of liquid alloys and vapor coexistence restricts the upper limit to rather small region of liquid solution existence at zinc edge of the state diagram.
Key words: zinc, thallium, pressure, alloy, phase transition.
Sargsyan L.Ye., Hovhannisyan A.M. Sulfide-zinc concentrate roasting with production of predominantly sulfate roasted product for effective leaching
Sulfide zinc concentrate roasting with high silver content has been investigated by thermogravimetry and differential-thermal analysis at polythermal heat schedule. Roasting at the temperature of 630±10 °C is shown to make provision of producing predominantly sulfate roasted product more applicable for effective recovery of zinc and other useful components.
Key words: sulfidezinc concentrate, thermogravimetry and differential-thermal analysis, sulfatizing roasting, oxide roasted product.
Samokhin A.V., Alekseev N.V., Lainer Yu.A., Tsvetkov Yu.V. Oxidation of organic impurities in processing aluminate solutions when thermal plasma jet affects
A new approach has been considered for purifying aluminate solution of the alumina production from organic impurities using solution processing with fast jet of oxidizing thermal plasma flowing in the solution volume. The conversion degree of initial organic compounds in excess of 80 % has been shown experimentally to be reached in plasma processing of water solutions of phenol and humic acids. Decrease in chemical consumption of oxygen more than by 60 % was observed in the above experiments, being indicative of significant organic impurity concentration reduction
Key words: thermal plasma, organic impurities, solution, aluminate, oxidation.
Golovnykh N.V., Bychinsky V.A., Tupitsyn A.A., Chudnenko K.V., Shepelev I.I. Technology optimization of cement production from waste of alumina production using physical-chemical model
A physical-chemical model of producing high-quality cement grades with application of alumina production waste: belite fine pulp, limestone, etc. has been developed. It allows keeping of optimal circuit inventory to give provision of efficient use of raw materials and energy of exothermic reactions in the process of charging components. The results of simulation afford opportunity to raise the product quality as well as to reduce the amount of gas-dust emissions.
Key words: alumina production waste, sintering, clinker materials, physical-chemical model, process optimization.
Arkhipov A.G., Polyakov P.V., Arkhipov G.V. The effect of technological and design parameters on integrity of aluminum electrolytic furnace bottoms during flame roasting
The effect of roasting process, cathode block materials as well as other factors on the integrity of the bottom during flame preheating of aluminum electrolytic furnaces has been investigated. Using the mathematical simulation in ANSYS finite-element and Star-CD CFD-packages, investigations of temperature fields, gas dynamics, stress-strained state of the electrolytic furnace during flame preheating have been carried out. The best version of peripheral seam covering in roasting is chosen.
Key words: aluminum electrolytic furnaces, mathematical simulation, roasting, service life.
Metallurgy of less-common and precious metals
Gudkov A.S., Zhuchkov I.A., Mineev G.G. Thermodynamics of interaction of sulfite-thiosulfate solutions with precious metals Materials science and heat treatment
The thermodynamic probability of precious metal dissolution in water solution of sodium thiosulfate, sodium sulfite and their mixture at the normal conditions (without solution heating) has been considered. The effect of impurities and catalysts (divalent copper, elemental sulfur, access of oxygen from the air to the solution, ammonia) is estimated. The theoretical calculations of reaction rates are carried out. A conclusion on expediency of application of sulfite-thiosulfate dissolving agents of precious metals from ores and concentrates is made as a result of the theoretical investigations.
Key words: precious metals, dissolution thermodynamics, sodium sulfite, sodium thiosulfate, water solutions of sulfur.
Materials science and heat treatment
Mylnikov V.V., Shetulov D.I., Chernyshov E.A. Fatigue resistance factor variation for some pure metals depending on the frequency of loading cycles
A comparative analysis of metal fatigue resistance variations of some pure metals: copper, zinc, cadmium, titanium, and others depending on frequency of loading cycles during bending deformation of revolving samples of 5 and 2 mm in diameter is given. Derived from cyclic loading, fatigue curves and microstructural changes are shown.
Key words: frequency of loading cycles, fatigue resistance, microstructure, surface damaging.
Belov N.A. Quantitative analysis of the Al-Zn-Mg-Cu-Ni phase diagram in the range of high-strength Nikaline compositions
Using “Thermo-Calc” program, the quantitative analysis of phase diagram for the Al–Zn–Mg–Cu–Ni system as applied to high-strength Nikaline alloys has been carried out. Taken Al–6%Zn–2%Mg–4%Ni base composition as an example, copper addition is shown to complicate essentially the phase composition. Taking weak effect on the liquidus of the base composition, copper significantly lowers the solidus (equilibrium and non-equilibrium), thus, on the one hand, restricting the possibility of high-temperature annealing and, on the other hand, it can affect adversely casting properties. On the strength of all the evidence of calculated and earlier obtained experimental data, a conclusion is made that copperless Nikaline alloys are preferable than copper ones.
Key words: phase diagrams, aluminum alloys, Nikaline alloys, Thermo-Calc.
Powder materials and coatings
Shemyakina O.A., Sheikhalieva Z.I., Sheikhaliev Sh.M. Production of soldering powders by centrifugal atomization of melt
The experimental plant for producing Sn–Pb and Sn–Cu soldering powders by centrifugal atomization of melt film is described. The effect of different parameters on median diameter (D50) and homogeneity of POS61 powder is found. It is ascertained that with increasing the disk rotating speed, the homogeneity of powder deteriorates and D50 value of the powder decreases and reaches 36 µm at the disk rotating speed of 25000 rpm. The optimal melt film height being equal to 15 mm has been experimentally determined, with which the minimal size of the powder particles is observed. The effect of oxygen on oxidation, fluidity, and bulk density of the powder has been studied. When oxygen content in the atomizing medium is 0,01 vol.%, the powder POS61 contains oxygen in the quantity of no more than 0,004 wt.%, fluidity is 11 sec, and bulk density is 4,98 g/m3.
Key words: experimental plant, soldering powders, centrifugal atomization, films, powder homogeneity, bulk density, powder fluidity.
Energy saving and environment protection
Matyukhin V.I., Yaroshenko Yu.G., Matyukhin O.V. Perfection of heating modes on shaft furnaces of nonferrous metallurgy
Based on the experimental data of researches of thermal and gas-dynamic works of shaft melting furnaces, basic regularities of development of thermal and gas-dynamic processes in the longitudinal and transversal sections of the unit are established. It is offered to change nonuniformity of the conditions of heat treatment of initial materials by improvement of gas distribution uniformity due to optimization of tuyere supply of air blasting and materials with the use of distribution devices. The efficiency of a number of proven methods to change technological parameters of the shaft melts is shown: organized gas extraction from a layer of charge materials, use of the acoustic field energy, heating of air blasting up to the temperature no lower than 300 °С, enrichment of blasting by oxygen, use of natural gas burnt directly in a layer.
Key words: shaft furnaces, uniformity of gas distribution, methods of shaft melt intensification.
Information
Naboichenko S.S., Kelchevskaya N.R., Goncharova N.V.
On problems of engineer training for enterprises of nonferrous metallurgy
Chronicle
Khorev Anatoly Ivanovich: to 50th anniversary of scientific and productive activity in creation of titanium alloys and technological processes of their production and application
