Nonferrous ore concentration
Pan’shin А.М., Yevdokimov S.I., Artyomov S.V. Magnetic fluid separation of goldcontaining products in vibration field
New data were obtained for the magneticfluid separation process based on the pondermotive action of magnetized separating medium, i.e. ferrofluid, on nonmagnetic bodies distributed in it. Ferrofluid magnetization in inhomogeneous magnetic field increases the acting bodyforce field density and, as consequence, the pressure gradient in it. The phenomenon may be considered as ferrofluid pseudoweighing and use it for separation of nonmagnetic materials by their specific weights, while controlling the magnetic field strength. The behavior of ferrofluid in vibratory field has been theoretically investigated and the vibration amplitude and frequency dependence of absorbed energy has been found. Under the production conditions, a series of tests has been carried out to extract free gold out of alluvial deposit flushing products by the magneticfluid separation technique, the results of which prove the prospects of involving secondary Aucontaining resources with hard to recover gold to processing.
Key words: magneticfluid separation, separator design, vibratory parameters, goldcontaining products, practice of schlich retreating.
Extractive metallurgy of nonferrous metals
Selivanov E.N., Nechvoglod O.V., Udoeva L.Yu., Lobanov V.G., Mamyachenkov S.V. Electrochemical oxidation of coppernickel sulfidemetal alloys
Electrochemical dissolution of coppernickel nis matte is considered as one of the versions of its processing. It is shown that anode oxidation of the material pertains to the regularities specific for its phase components: nickel, copper and nickel sulfides. The subsequence of phase oxidation, the effect of potential sweep rate on limiting oxidation currents, and peculiar properties of passivating film formation have been found.
Key words: electrochemistry, sulfides, copper, nickel, nis matte, polarization, passivation, potential, current density.
Chubarov А.V., Maksimenko V.V., Belousova N.V. Investigation of elemental sulfur behavior in H2O–OH––CN– solutions
The processes of elemental sulfur dissolution have been investigated in the S–H2O–OH––CN– systems simulating the Au cyaniding and sorption leaching processes out of biocakes from goldseparating productions in a range of concentrations of CN– ions: 0?0,02 mole/dm3 and OH– ions: 0?0,1 mole/dm3. Having applied the method of simplexlattice planning of the experiment, mathematical models and "solvent composition – amount of dissolved sulfur" diagrams for temperatures of 20, 30, and 40 °С are obtained. It was found that cyanide concentration affects the S solubility in the strongest manner in concerned systems at t = 20 °С, and ОН– content gives a major contribution in improvement of S transfer into the solution. The CN– hydrolysis process role in increase of sulfur solubility in the studied systems is shown.
Key words: elemental sulfur, cyanides, alkali solutions, solubility, hydrometallurgy of gold, simplexlattice planning of experiment.
Lin’kov V.A., Temiraev О.B. Investigation of ammonia sulfate production process out of coppercontaining solutions by means of copper cementation by aluminum
A research of aluminum sulfate production by means of copper cementation from the solutions by aluminum has been carried out. The greatest effect on the process rate is shown to take the copper content in the solution, then time and sulfuric acid concentration: X1 ³ X3 ³ X2, or in the dimension scale: Cu ³t ³ H2SO4.
Key words: aluminum sulfate, copper cementation by aluminum, Dow process.
Bazhov P.S., Sviridova M.N., Tanutrov I.N. Sulfidemetal alloy processing from melt of germaniumcontaining raw material
The process is proposed to increase general germanium extraction from sulfidemetal alloy by Ge afterextraction in the electric furnace of the primary melt in the form of sublimates, which meet the requirements of the further processing into germanium concentrate. The technical and economic indexes are obtained to ensure increase of production profitability.
Key words: germanium concentrate, technology improvement, sulfidemetal alloy, extraction, germanium.
Komkov V.G., Gostishchev V.V., Ri E.Kh. Physicalchemical aspects of carbothermic reduction of tinstone in ionic liquid melt
The conditions of carbothermic reduction of tinstone concentrate in the melt of Na2CO3NaNO3 salt system (1:0.3) are studied. The composition of charge material is found and the temperature range (600–900 °С) of reduction is determined. It is shown that in interacting tinstone with melt, intermediate Na2SnO3 compound is formed, which is mainly reduced by CO gas in liquid phase of the melt at high speed (1,5 h), providing recovery of 97 % tin from tinstone concentrate into crude alloy.
Key words: tinstone, carbothermic reduction, salt melts, crude tin
Isaeva L.А., Braslavsky А.B., Polyakov P.V. The effect of αphase content and grain fineness on alumina dissolution rate in aluminacryolite melts
Alumina dissolution rate and mechanism in aluminacryolite melts have been determined based on the results of dissolution time measurement, the visual observation and study of alumina agglomerates using electronic microscope. The alumina samples obtained from different supplier and being different in phase and grain fineness were dissolved in the course of the experiences. It was found that alumina dissolution rate is reduced with increasing α Al2O3 and –45µm fraction contents as well as the initial Al2O3 concentration in the electrolyte. Particles of size >150µm and alumina in which their content reaches 31 % dissolved slower than that contained –45µm fraction. The photos of agglomerates formed after alumina loading and their microstructure images are given. The dissolution rate data are explained on the basis of alumina weight amount behavior in electrolyte related to γAl2O3 in α Al2O3 recrystallization and interlinking A α l2O3 platelet network formation.
Key words: alumina, aluminacryolite melt, dissolution rates, α phase, grain fineness, agglomerates, recrystallization, γAl2O3, α Al2O3.
Gildebrandt E.М., Vershinina E.P., Frizorger V.К. Coke particle sedimentation in liquid in cokepitch composition of Soderberg anode
The studies carried out on the anode of aluminum electrolyzer have shown nonuniformity of coke particle distribution throughout the height of cokepitch composition zone. This is connected with sedimentation of large fractions of coke charge in viscous medium. Investigation of large coke particle sedimentation has been carried out on liquid cokepitch composition model at the laboratory conditions; the characteristics of the process are determined. The coke charge composition has been proposed to provide sedimentation stability of anode mass in the zone of the cokepitch composition zone of Soderberg anode.
Key words: aluminum electrolyzer, Soderberg anode, pitch, coke, cokepitch composition, sedimentation.
Casting production
Pashkov А.I., Gerasimov S.P. On application of mechanical alloying to produce the Cu–Mn–Ni system alloys used as brazing alloys
Comparison of methods to produce alloys of the Cu–Mn–Ni system has been carried out: with preliminary mechanical alloying of the components and direct melting. It was found that the first process provides for essentially lesser melting loss of manganese (approximately twofold) as compared with the second method, being very important for preparation of brazing alloys with strictly regulatory additives. With increasing time of treatment of mechanicallyalloyed materials, their temperature properties are shown to comply with the alloys produced by direct melting of the components. The proposed method is regarded as promising for production of comparatively small quantities of alloys from the components essentially differed in density, melting temperature, volatility, interaction with gases, and other physicalmechanical properties.
Key words: mechanical alloying, manganese, nickel, Cu–Mn–Ni system, treatment, melting loss, brazing alloy.
Kats А.М. To the crystallization theory and casting and ingot structure formation
The article is devoted to development of crystallization theory and estimation of the effect of cooling conditions on the ingot structure for the purpose of clarification of the reasons related to ambiguous linking of grain sizes with cooling conditions as well as between macrostructure and microstructure. As a result, a macrograin size formation concept taking account of the joint effect of cooling rate and the action of insoluble impurities on the crystallization center generation rate has been proposed and verified on the generalized experimental data. The scientific explanation of different link versions of grain sizes with cooling rate and macrostructure with microstructure.
Key words: crystallization theory, cooling conditions, grain size, macrostructure, microstructure, impurities.
Metal forming
Biyakaeva N.Т. Investigation of regularities in metal structure change in simple share
The effect of simple shear on the structure and the property of metals and alloys to be forged has been considered. An analysis of the results of the metal structure investigation carried out with specimens of a certain configuration shows metal working in the conditions of shear deformation development across the blank section results in intensive grain reduction.
Key words: simple shear, special specimens, degree of working, specimen metal structure, primary recrystallization, plastic strain, temperature nonuniformity, strengthening, titanium alloy.
