Mineral processing of nonferrous metals
Lavrinenko A.A., Krasnov G.D., Krapivny D.V., Frolov O.N., Shimkunas Ya.M. The main features of pneumopulsating flotation process
The paper gives the results of experimental and theoretical studies as well as an analysis of the effect of alternating pulsating impacts of liquid flow on the conditions of phase interaction in pneumopulsating flotation. Increase in the rate of bubble floating-up and its effect on bubble coalescence, reduction of induction time, increase in detachment force of a particle from a bubble in the dynamic conditions as well as movement of particles over a bubble from the position of lower equilibrium are found. Dispersion of bubbles formed with the help of the pneumopulsating aerator has been investigated. Raising the probabilities of flotation process and selectivity of mineral separation, which calls forth the high effectiveness of the pulsating flotation and is determined by amplitude-frequency mode, is shown.
Extractive Metallurgy of Nonferrous Metals
Trofimov E.A., Mikhailov G.G. Interaction of nickel to oxygen in molten copper
Using the theory of phase structure with a collective electron system, temperature dependencies of equilibrium constant, and interaction parameter method, equilibrium nickel and oxygen concentrations in molten copper depending on the composition of slag phase were calculated. Oxygen solubility surface in the metallic melts of the system Cu- Ni- O was plotted. Experimental examination of the calculation results was carried out, giving evidence of satisfactory coincidence of the results.
Natorkhin M.I. Extraction of silver metal during hydrometallurgical processing of lead-zinc stocks
An opportunity of extracting silver metal out of silver-lead sponges with the help of muriatic dissolution was investigated. A basic technological scheme and process operation were developed.
Golovnykh N.V., Bychinsky V.A., Evseev N.V. Thermodynamic analysis of dissolution processes of sodium aluminates and chromates in alkaline solutions
Dissolution of sodium aluminates and chromates in alkaline solutions were studied by computer simulation of physical-chemical equilibria. The temperature effect of aluminum solubility decreasing in the system was found to run to 31 % and the effect of air content did 4 %. At molar ration Cr/Al = 0,08, addition of chromates can reduce aluminum solubility by 14 %. The free oxygen (air) content determines the degree of chromium oxidation. Cr(VI)/Cr(III+VI) ratio is RCr = 48¸ 100 % in closed and opened systems respectively.
Metallurgy of less-common and precious metals
Kritskaya E.B., Miroevsky G.P., Burylev B.P., Moisov L.P. Physical and chemical properties of melts of the magnesium chloride–manganese chloride system
Surface tension and density were experimentally measured by the technique of maximum gas pressure in a bubble as well as saturated vapor pressure was measured by the technique of boiling points at different temperatures. The isotherms of studied and computed properties were plotted and assumptions on structure and behavior of deviation from ideal solution laws were made.
Casting Production
Balashova N.P. Estimated strength of castings on basis of taking metal microstructure non-uniformity into account
Using experimental castings (cylinders of diam. 15, 20, 30 mm) of Al + 3 % Cu alloy, it was established by measurement of sizes of a dendritic cell and a portion of non-equilibrium eutectic that these parameters vary according to curves with extreme at about a half of the cylinder radius on the section from the surface to the casting center. Local and average strengths of the experimental castings of Al + 3 % Cu alloy were estimated with using well-known dependences of tensile strength of the alloy on a dendritic cell size. Calculation of the average tensile strength permitted to find that the average strength of the alloy distinctly rises when the radius of a cylindrical casting decreases. This makes it possible to assume a possibility of metal saving at the cost of casting diameter reduction with keeping the general structural strength the same.
Metal forming
Skotnikov I.A., Mochalov S.N., Kotov V.V., Galkin A.M., Pruzhinin I.F., Mironov P.V. A study of technological deformability of МНЖМц 10-1-1 alloy
Plastometric studies of МНЖМц 10-1-1 copper-nickel alloy were carried out at the conditions of hot and cold deformation as applied to extruding process, cold rolling, and coil tube drawing. An anomalous effect of deformation rate on resistance to deformation and ultimate ductility of the alloy studied was found. Technological recommendations to employ the test data are given.
Physical Metallurgy and Heat Treatment
Belov N.A., Koltsov A.V. Phase diagram of Al- Cu- Fe- Mg- Si system in Al- Cu-rich alloys
The Al- Cu- Fe- Mg- Si phase diagram was assessed in the Al–Cu-rich region including the solidification reactions and the phase distribution in the solid state. Subject to obligatory presence of all alloys related to the examined range of aluminum solid solution (Al) and Al2Cu phase, the effect of magnesium, copper, and iron can be represented on the plane of concentration triangle by analogy with quaternary equilibrium diagrams. The invariant eutectic reaction L Þ (Al) + Al2Cu + Mg2Si + Al7Cu2Fe + Al2CuMg was experimentally confirmed in the quinary equilibrium diagram.
Muratov V.S., Zakamov D.V., Sarov D.S., Alyangina O.S., Glotova Yu.S. Contact-reactive soldering of aluminum alloys with noncorrosive flux NOKOLOKThe results of trying out the soldering process of domestic aluminum alloys using NOKOLOK flux (manufacturer “Solvay fluor und derivate. GmBH”, Hanover, Germany) with silicon additives are given. The effect of silicon introduced amount on activity of flux spreading, joint quality, and microstructure of the juncture in the course of furnace soldering of splices, T-joints, and interlocks has been studied. A reliable soldered joint (alloy AD) can be produced at silicon content of 2- 3 % in the flux, furnace temperature of 630- 650 ° C, duration of staying the specimens in the furnace 3- 5 min.
Powder Materials and Coatings
Laptev A.I., Manukhin A.V., Sannikov D.S., Yermolaev A.A. Mechanical properties and phase composition of carbonado synthesized in different metal systems
The effect of different catalyzing alloys used in synthesis of polycrystalline carbonado diamonds on their composition and mechanical properties was studied. Strength of polycrystalline diamonds was found to depend on the composition of carbonado binder defined by the composition of the catalyzing alloy used. Presence of carbides results in embrittlement of the binder and decrease in strength of polycrystal as a whole.
Titlyanov A.E., Radyuk A.G., Kozlov S.N., Purekhov A.N. A study of wear resistance of gas-thermal coatings made of copper-based alloysWear resistance of gas-thermal coatings of copper alloys as compared with that of M1 grade copper was studied. Coatings of МНЖКТ alloy (composition, %: Mn - 0,3¸ 0,8, Si - 0,15¸ 0,3, Ti - 0,1¸ 0,3, Ni - 5,0¸ 6,5, Fe - 1,0¸ 1,4, Cu - rest) were applied by arc spraying (starting material was wire), and Бр. АЖ 9-4 coatings (Al 9,5, Fe 4, Cu rest) did by flame spraying (starting material was powder).
Structural Macrokinetics. Self-Propagating High-Temperature Synthesis
Kruglova N.V., Raskolenko L.G., Maksimov Yu.M. Self-propagating high-temperature synthesis of three-component systems on basis of titanium and alloys of III, VI, VIII groups with nitrogen
The processes of phase formation at combustion of complex mixtures in nitrogen using Ti, Al, Cr, Fe, Co metal powders of different dispersity were studied. Relative density of the starting mixtures changed within 0,2- 0,6. Combusting specimens were quenched by dropping them into water to study phase-formation mechanisms. The final and quenching combusting products were analyzed by X-ray diffraction analysis in DRON-3 device. In the course of the study, the intensive processes of phase-formation of metal nitrides were found to occur inside T- S solid-liquid range complying with the phase diagram of starting components. The X-ray diffraction analysis revealed novel nitrides of starting metals, which could not form under the normal conditions.
Amosov A.P., Fedotov A.F., Yermolenko M.A. Features of macrostructural state and compaction mechanism at power SHS-compaction of hard-alloy materials
The process of initial macrostructural state and density formation of products in the course of self-propagating high-temperature synthesis (SHS) in the systems Ti- C- Ni and Ti- B has been analyzed. Relative density of the solid phase was found to be less than apparent density in the presence of the melt, and the synthesized products are in a suspension aerodispersed state. Features of the solid-liquid SHS product compaction process are considered. The anomalously high initial compaction rate was shown to be related to aerodispersed state of the synthesized products since resistance to deformation is negligible during the synthesis. Occurrence of specific horizontal areas of the zero compaction rate on the compaction curves is caused by nonlinear (thixotropic) nature of viscous flow of the refractory phase.
Emelianov A.N., Shkiro V.M., Rogachev A.S., Rubtsov V.I. Electric and thermal conduction of powder mixtures on basis of titanium for self-propagating high-temperature synthesis of materials
Electric and thermal conduction of industrial powder titanium and spherical powder titanium of 0,2- 1,2 mm in size were measured. Thermal conduction of an interparticle contact zone (~ 10- 5 W/m× K) in powder titanium has been estimated. A thin layer of low thermal and electric conduction on the surface of titanium particles remains in compacted powder billets right up to 80- 90 % of relative density. A large difference in thermal conductivity of the particles and interparticle contacts results in a thermal microheterogenous combustion wave (SHS) and go-ahead modes of solid flame propagating front.
Surface engineering. Multifunction films. Corrosion and metal protection
Ostrikov O.M. Irregularities of indentation relief by Vickers indentor on surface (111) of bismuth monocrystal
The paper studies the effect of electric pulses of 10- 4 s in duration, up to 600 A/mm2 in density as well as simultaneously acting magnetic field (0,2 T) orthogonal to the direction of electric field density vectors and action of concentrated load on the indentation roughness by Vickers indentor. The indentation roughness is found to occur seldom in absence of outer electric impacts. A portion of unevenness in the indentation increases in case of simultaneous action of the concentrated load, pulsed electric current, and magnetic field.
Process Control and Automation
Salikhov Z.G., Khodov N.V., Danilin E.N. Determination of static characteristics of low-temperature alkaline melting of lead concentrates
Based on the experimental data, the static characteristics of process parameters of a new promising process of low-temperature alkaline melting of lead concentrates such as temperature, alkali and concentrate consumption, melting duration, melt viscosity have been determined. The characteristics were used for determination of rational values of the parameters of this process.
Chronicle
The 60-th Anniversary of Stanislav Stepanovich Naboichenko
