Mineral Processing of nonferrous metals
Urumov G.T., Khadonov Z.M. Distinctions of the grinding process in centrifugal mill
Having minimum mass and overall dimensions as compared to existing ones, a centrifugal mill is described. It provides for improved effectiveness in particle size reduction at the expense of rational interacting the trajectories of the grinding body and ground material. The mill consists of a support platform with rigidly mounted legs on which a case with a spherical or ellipsoidal chamber and a rotary platform and case drives are mounted in bearings. The drives make it possible to rotate the case relative to two axes crossing in its center. The shape of the grinding body is similar to the chamber shape. The mill can also operate in self-grinding mode. The design values of accelerations normal to the case surface were obtained and the equations of movement of the point placed on its surface were derived for the spherical case rotating with equal transportation and relative angular velocities relative to two mutually perpendicular crossing axes.
Extractive metallurgy of nonferrous metals
Natorkhin M.I. A study of nickel sulfide leaching by sulfite-ammonia electrolytes
The kinetics of millerite NiS and nickel concentrate Ni3S2 dissolution in sulfite-ammonia electrolytes is considered. Electrochemical behavior of NiS in 1M (NH4)2SO3 at different potential sweep velocities has been shown and a dependence between peak current and square root of potential sweep velocity was derived. Problems of wasteless technology of nickel sulfide processing are concerned too.
Burylev B.P., Moisov L.P., Tsemekhman L.Sh. Pressure of saturated vapor over molten cobalt and cobalt-oxygen alloys at different temperatures
An evaporation method from cylindrical crucibles of different height-to-radius ratios in vacuum was used to study the heterogeneous equilibrium of liquid-vapor for melted cobalt with little content of dissolved oxygen at 1823 K and 1873 K. Temperature dependencies of pressure of saturated liquid cobalt vapor and component evaporation coefficients as well as cobalt evaporation rate from cobalt–oxygen melts were experimentally calculated.
Katkov O.M. Reducer activity during melting silicon in electric-arc furnace
When melting silicon in electric-arc furnace, the reduction of silicon oxide from charge at 2000 ° C and above takes place successfully by carbon, silicon carbide, and silicon. When melting lump charge in the open electric furnace, of great importance are adsorption capacity and reactivity of the reductant, mainly charcoal, which actively reduces silicon dioxide, adsorbs and filters silicon monoxide, an unavoidable intermediate product removal of which determines silicon losses during melting, from reaction gas. When melting briquetted charge, reduction of thin materials mixed and compacted in a briquette takes place at high temperature more complete and at higher rating as compared to melting of lump charge. Dispersion ability of petroleum coke and coal compensates high adsorption capacity and reactivity of the charcoal, which can be excluded from the charge without worsening the results. The use of pure petroleum coke and coal in agglomerated charge instead of deficit charcoal leads to the decrease in prime cost of silicon at the expense of application of new, less deficit materials, improvement in grade of product quality, and decrease in consumption of raw material and energy.
Vorobiev I.B., Nikolaev I.V., Kirov S.S., Osipova E.N. Properties of sodium-potassium aluminate solutions
Density and viscosity of sodium-potassium aluminate solutions have been studied in dependence on alkali concentration, caustic module, and temperature. Nonlinear nature of the properties studied is evidence of their connection with structural changes in aluminate solutions.
Lainer Yu.A., Yampurov M.L., Syzdykova A.O. Physical-chemical properties of solutions and solid phases in the Al2(SO4)3-Fe2(SO4)3-FeSO4-H2SO4-H2O system
Solubility of aluminum sulfate has been examined in the presence of ferric and ferrous sulfates. It is shown that the process temperature and concentration of sulfuric acid affect on the solubility and phase composition of aluminum sulfates. Crystallization conditions of aluminum and ferric sulfates were determined. Al4SO4(OH)10·36H2O, Al4SO4(OH)10·5H2O, Al2(SO4)3·18H2O, Al2(SO4)3·17H2O, Fe2(SO4)3´ 10H2O, Fe2(SO4)3·7,5H2O, FeSO4OH·3,5H2O and HFe(SO4)2·4H2O are solid products in the system Al2(SO4)3-Fe2(SO4)3-FeSO4-H2SO4-H2O. The solid phase in the system Al2(SO4)3-Fe2(SO4)3-FeSO4-H2SO4-H2O is presented by similar compounds as in the system Al2(SO4)3-Fe2(SO4)3-H2SO4-H2O, but in addition, a double salt of FeAl2(SO4)4·22H2O composition is formed too. Deviation of specific electrical conduction of the solutions from additive values is evidence of double salt formation.
Metallurgy of less-common and precious metals
Kozin V.F., Omelchuk A.A. Gallium refining in salt melts containing its compounds of the lowest oxidation states
A method has been developed of gallium refining using bipolar gallium electrodes in molten electrolytes that contain its compounds of the lowest oxidation states. A gallium(I)-b -aluminous membrane was used to separate electrodes and bipolar electrodes. The effect of electrolysis conditions on gallium transfer from the anode to the cathode through the gallium(I)-b -aluminous membrane has been studied. It has been shown that the gallium refining in molten electrolytes makes it possible to produce metal of high purity with the current yield that is three times as compared to current yield in aqueous electrolytes.
Begunov A.I., Yakovleva A.A. Kinetic behavior of gallium dissolution in sulfate solutions
Dissolution of gallium in sulfuric acid and aluminum sulfate solutions has been studied in the range of temperatures 286-355 K using the gravimetric analysis. It has been shown that apparent activation energy is in the range of 25-85 kJ/mole. Judging from the activation energy obtained, dissolution of solid gallium is determined by characteristics of the solid-phase reaction of oxide formation on the specimen surface, and diffusion restrictions have the effect on liquid gallium dissolution.
Petrov G.V., Greiver T.N., Vergizova T.V., Smirnov M.Yu., Vazhgin I.V. To the question of behavior of platinum metals during decomposition of platinum-bearing concentrates by “oxidizing roasting–chlorine leaching” method
The “oxidizing roasting–chlorine leaching” method, used for decomposition of platinum-bearing concentrates produced as a result of chromite and low-sulfide raw dressing, fails to ensure complete extraction of platinum metals into chloride solution, as connected with the formation of passivating films, composed of strong oxides, on the surface of metallized platinum metals. Application of hydrometallurgical reduction of cinders of platinum-bearing concentrates with the help of preliminary introduction of hydrochloric sodium or sodium sulfite is followed by the removal of oxide films that helps significant improvement of platinum metal extraction into chloride solution.
Metal forming
Pupyshev A.A., Bogatov A.A., Orlov G.A., Akchu-rin R.Z. Geometrical and kinematic restrictions during periodical drawing of tubes
The results of analytical investigation related to periodical drawing of tubes are given. The correlations between velocity of tube feed, supplementary shaft radius, angular velocity of shaft rotation, and length of calibrating shoulder of drawing die were obtained. The relationships for calculation of sizes of the volumes marked out are offered. The rational parameters of the drawbench setting and the tool sizes are recommended to produce thin-walled tubes without longitudinal variations of wall thickness.
Nesterov D.V., Romanenko V.P., Kharitonov E.A. To the question of calculation of roller calibration for production of roll-formed sections
A method of designing the roll pass design for the production of roll-formed sections is considered. The results of calculation as tensors and functional dependences make it possible to use them for mathematical simulation of the process and hand over dimensions to execute the design roller drawings.
Raab G.I., Valiev R.Z. Equal-channel angle compaction of long-measuring bars
Pilot technological equipment was developed to investigate the process of equal-channel angle compaction at room temperature of metals as wire and long-measuring bars. Hard-drawn wire made of pure aluminum was used for the pilot work. As a result of the investigation, a dynamic behavior of mechanical characteristics of the wire was found depending on the deformation intensity and compaction route. The structural state of the starting and deformed workpiece was estimated by metallography.
Physical metallurgy and heat treatment
Barsukov A.D., Trots V.S., Khachaturyan A.A. On calculation of atomic volumes of crystalline lattice in several two-component non-cubic solid solutions
Atomic volumes of several two-component non-cubic solid solutions were calculated. A model is proposed which is based on the concept of the number of bonding electrons. A good accordance was obtained between experimental and design values of atomic volumes.
Powder materials and coatings
Bukaemsky A.A., Tarasova L.S., Fedorova E.N. Study of distinctions of phase composition and stability of nanosized Al2O3 explosive synthesis
The phase composition of nanosized powder Al2O3 produced by the explosive technique was studied by X-ray phase and differential thermal analyses. It is shown that the material consists of d - and q -oxide modifications, the surface layer of a particle having specific thickness of 1,6 nm and consisting of q -Al2O3. Stability of nanosized Al2O3 was studied in regards to static annealing and shock-wave impact. Absence of d ® q -phase transition is a distinction of this material.
Ermolaev A.A., Laptev A.I. Effect of oxygen and hydrogen-bearing impurities on synthesis of polycrystalline carbonado diamond
A study is of the effect of BaO2, C10H8 and H2O impurities in catalyzing alloy on the formation process and properties of polycrystalline carbonado diamonds. It was found that their introduction results in the temperature rise of carbonado diamond formation synthesized at 7,7 GPa as well as in extension of the incubation period when forming carbonado synthesized at 9,0 GPa.
Oglezneva S.A. Rapid-method of determination of specific consumption of diamonds in laboratory conditions
A rapid method was developed concerning the determination of specific consumption of diamonds, making it possible to reliably estimate operational capability of the tool, using friction machine SMTs-2 and minimum consumption ~ 1,5–2 g of the material tested. The main distinction of the method is rigid fastening of diamond tool specimen with the rotary movement of the material treated.
Surface engineering. Multifunction films. Corrosion and metal protection
Levashov E.A., Kudryashov A.E., Malochkin O.V. Prospects of SHIM-3B alloy application modified by nanosized ZrO2 powder in the process of electrospark alloying
The work studies the kinetics of mass transfer of SHS-electrode materials (including those with additions of nanocrystalline powder of stabilized zirconium dioxide) onto die steel of 5ХНМ grade under different power modes. Studies of the structure and properties (thickness, uniformity, microhardness, phase composition, wear-strength) of coatings produced by electrospark alloying have been carried out.
Process control and automation
Belova I.K., Deryugina E.O. On classification and properties flowing computers for scientific studies
Computation systems, including associative conveyor memory as a main functional component, show great possibilities for organization of parallel computations. At present time there are different models of parallel computation systems making it possible to simultaneous processing of large information contents, which use one or other properties of functional facilities in constructing the systems. The models of flow computations are the most interesting from the standpoint of hardware-software realization, among which the models with interlocking, acknowledge signals, buffering of data, and code copying should be emphasized. A priori analysis showed that the models with code copying are prospecting, including actor ones which propose effective execution of parallel computations at the expense of the possibility of simultaneous activation of several copies of the same actor controlling the computation process run.
Economics and Management
Garbuz D.N. Influence of taxation schemes on the efficiency of investment project.
The article quotes a model for optimization of enterprise taxation scheme. When the main assets are placed into the balance, the analysis of tax payments under different schemes of accounting is effective.
