Mineral processing of nonferrous metals
Druzhina G.Ya., Dement'ev V.E., Mineev G.G. Raw materials sources of Russia and countries of the CIS for gold mining by heap leaching
Based on the data of the experimental investigations, the raw materials sources of Russia and other countries of the CIS are analyzed for gold mining (and silver as well) using cyanide heap leaching.
Extractive metallurgy of nonferous metals
Sin'ko A.V., Belousova S.V., Luchitsky S.L. Forms of copper ions being in nickel sulfate-chloride electrolyte and their effect on the process of its cementation
Forms of copper ions being in nickel sulfate-chloride electrolytes were experimentally determined. Copper ions were found to be represented both in cationic form and as chloride complexes, quantity of Cl in ligand depending on Na concentration in the electrolyte. Increase in a portion of chloride complexes with chlorine content in the ligand > 2 results in higher apparent reaction orders of Cu cementation process and this, in turn, reduces effectiveness of the process.
Mamyachenkov S.V., Anisimova O.S., Orlov E.G., Kirpikov A.S., Khilai V.V. Processing of arsenic-containing solutions from the department of wet purification of gases at sulfuric production
The article gives the results of investigations concerning the technique of processing arsenic-containing solutions from the department of wet purification of gases at copper smelters. Compositions of circulating solutions and purification products were found and material and water balances of the process flowsheet and distribution of metals in the products were calculated.
Partenov D., Stefanova V., Avramov A., Chimbulev M. Kinetics of polymetallic concretions leaching in SO2 water solution
Kinetics of reducing leaching of manganese and non-ferrous metals from polymetallic concretions in SO2 water solution was studied. The effect of the process variables on leaching process (mixing rate, temperature, concentration, particle diameter) was determined. The process is established to be controlled by SO2 diffusion to the reaction surface, as confirmed by high values of apparent activation energy (16,6 kJ/mole), mass-transfer coefficient (ks = 1,15× 10–2 cm/s) as well as by the reaction order in respect of the reagent (n = 1), and mixing rate dependence of extraction rate. The following kinetic equation of the manganese leaching process was derived in an integral form:
Burylev B.P., Tsymbulov L.B., Tsemekhman L.Sh. Solubility of carbon and activity of components in the Ni-S-C system
Carbon solubility was investigated experimentally in nickel melts using isothermal soaking at T = 1673 K. Its value smoothly decreases when sulfur is added. The design equations of carbon solubility and component activity were obtained. The interaction parameters in Ni–S–C melts were determined.
Gurevich R.A., Balmaev B.G., Lainer Yu.A., Balmaeva L.M. Modeling of process of aluminum-containing sulfuric-acid pulp filtration
The process of aluminum-containing sulfuric-acid pulp filtration was studied. A mathematical model and optimum filtering conditions: T = 70 oC, material size of 0,2 mm, sludge layer thickness of 4 mm, added flocculating agent mass of 30 mg/l, quantity of sulfuric acid to 100 % stoichiometry, content of residual carbon of 0,47 % were determined. The design productivity of filtration is 266,2 kg/(m2× h) and the experimental one is 232,48 kg/(m2× h). The effect of hydrodynamic and physical-chemical factors of filtration capacity and rate was studied. It was found that system polydispersity as well as presence of silicon in the solution and its capability to gel formation play the main part in the process of sulfuric-acid pulp filtration.
Metallurgy of less-common and precious metals
Skorokhodov V.I., Goryaeva O.Yu., Rаdionov B.K., Naboichenko S.S., Dynkina A.A.Choice of optimum ionite structure for palladium sorption out of nitrate solutions
The experimental data of palladium sorption from synthetic nitrate solutions by ion exchangers of various structures of functional groups are given. Palladium in such groups was shown to form a number of complex negative ions. Equilibrium of palladium ions was investigated in the nitrogen acid concentration range of 0,1–8,0 M. Palladium was found to be noticeably sorbed by every investigated ionite in subacid solutions. At high HNO3 concentrations, palladium sorption is insignificantly changed only for the ionites that have chelate groups. A proposal is made on the chemical nature of interaction of functional ionite groups with palladium in nitrate solutions. Some recommendations concerning the choice of ion exchangers for solving particular technological tasks are given.
Shibanov V.N., Khadykina E.A. Separation of copper and nickel by sulfite-carbonate technique
The conditions of formation of copper sulfites and monoxide have been analyzed on the basis of calculated diagram pKsy–pH. Lack of complexing at pH = 1,61¸ 6,89 between nickel (II) ion and sulfite ion was shown by spectrophotometric and chemical analyses. A sulfite-carbonate technique was proposed during processing high-acidic copper-nickel solutions. By the example of industrial copper electrolyte, residual copper (I) in nickel solution was shown to be in the range of 0,11–1,43 g/dm3 at T = 5¸ 9 ° C. The rest copper and all trace contaminants are concentrated in the sediment the basis of which is copper (I) sulfite Cu2SO3× nH2O.
Casting Production
Znamensky L.G. Processing of aluminum melts by refractory metal halides in the field of nanosecond electromagnetic impulses
Application of nanosecond electromagnetic impulses (NEMI) was considered in processing of aluminum melts by refractory metal halides. The NEMI effect on the concerned system of 1000–1500 MW/m3 specific capacity was shown to increase melt fluidity. Refractory alloying elements have a modifying effect and evolving gas products create conditions for effective refining of the melt. Compact globular intermetallic inclusions of 3–8 m m in size, which determine improvement of physical and mechanical characteristics of silumins, are formed during high-powered electropulse influence along the grain boundaries of aluminum alloys. Use of foundry alloys of aluminum-refractory metals prepared with NEMI and silumins makes it possible to improve quality of manufacture of thin-wall profilecomposite castings by precision molding technique.
Metal Forming
Lekhov O.S., Baranov M.V., Minakov V.S. Mode of deformation of metal in producing aluminum sheet in the continuous casting plant and deformation
The results of a theoretical study are given concerning production of aluminum sheets in a continuous casting plant and deformation. There determined the normal and contact stress distribution diagrams within a range of bending of narrow side walls of an envelope with liquid phase and in the area of deformation source as well as influence of non-detachable crystallizer wall coupling radius on the level of stretching strains and stresses. A computational experiment on the basis of solving the continuum mechanics problems by finite-element method was used as a testing method.
Vaisburd R.A., Gubernatorov E.I. Hollow cylinder pressing processThe hollow cylinder pressing process has been investigated. A dependence of p/s s ratio on the cylinder height, friction coefficient, and geometrical characteristics of the process was obtained on the basis of the metal deformation scheme chosen with the use of the principle of minimum full deformation energy. The effect of different parameters on p/s s value was analyzed.
Physical Metallurgy and Heat Treatment
Pozdnyakova A.V., Portnoi V.K. Features of structural changes during superplastic deformation of AMg4 alloy
Quantitative metallography was used for studying structure change in the process of superplastic deformation of AMg4 alloy. Evidences of dynamic recrystallization were found in the sections of specimens, thus confirming the features of superplastic deformation that were found earlier over sheet surface.
Powder Materials and Coatings
Maly E.N., Dedov N.V., Kutyavin E.M., Sennikov Yu.N., Soloviov A.I., Stepanov I.A., Makeev A.A., Lyubimova L.L. Production of superdispersed powders for cathode masses of lithium-ionic rechargeable batteries by thermal decomposition of salt solutions in plasma jet
Superdispersed powders of LiCoO2, LiNiO2, and LiMn2O4 have been produced by thermal decomposition of mixed solutions of lithium nitrates and respectively nickel, cobalt or manganese. Use of plasma-chemical process for synthesis of cathode masses of lithium-ionic rechargeable batteries is shown to be expedient. Single-phase crystalline structures of powders of the Li–Co–O, Li–Ni–O, and Li–Mn–O systems with the use of LiCoO2 powder used have been synthesized. Prototype samples of lithium-ionic rechargeable batteries with charge and discharge characteristics close to the values of commercial ones produced by “Sony” were manufactured. A possibility of purposeful change of crystalline structure of cathode materials by means of varying the temperature mode in the plasma-chemical reactor and the ratio of concentrations of salt-forming elements in the starting solutions was shown.
Maly E.N., Dedov N.V., Soloviov A.I., Istomin V.Ya., Lepakova O.K., Shkoda O.A., Naiborodenko Yu.S. Features of forming microstructure of piezoelectric materials on the basis plasma-chemical superdispersed powders of LZT type
The process to form the microstructure of piezoelectric materials on the basis of plasma-chemical superdispersed powders of lead zirconate-titanate (LZT) type produced by denitration of nitrate solutions in HF-plasma discharge by example of LZT St-5 and LZT-38 was investigated. The phase composition of sintered samples was determined by diffraction method and their microstructures did by metallographic method. The investigations executed have shown the single-phase products to form at Tsint = 1100 ° C and t sint > 5 min. Sintering is accompanied by the processes of collecting recrystallization. An optimum sintering mode for both powders was determined when ceramics with isomeric grain structure, minor grain size spread, and higher electrophysical properties.
Levashov E.A., Kudryashov A.E., Mishina E.S., Vakaev P.V., Zamulaeva E.I., Sviridova T.A. A study of kinetics of formation, structure, composition, and properties of electrospark coatings of modified electrode materials on the basis of TiC–KhN70Yu applied on OT4-1 titanium alloy
The effect of nanodispersed additives (ZrO2, Al2O3, W, WC, WC–Co, NbC, Si3N4) on mass transfer of SHS-electrode materials on the basis of TiC–KhN70Yu was studied at different processing powers. A complex of investigations of electrospark coatings (structure, phase composition, thickness, uniformity, microhardness, and heat resistance) was carried out over OT4-1 titanium alloy. An optimum mode of application of ESA-coatings was found using new modified electrode materials in the HF-plant “Alier-Metal” (E = 0,13 J, f = 3000 Hz). It was established that introduction of a nanodispersed component into the electrode material furthers increasing mass transfer, thickness growth, uniformity, microhardness, and heat resistance of ESA-coatings.
Structural Macrokinetics. Self-Propagating High-Temperature Synthesis
Manukhin A.V., Kupreeva G.A., Dvoretsky P.V. Study of some properties nonstoichiometry titanium carbides produced by SHS-compaction
Unique physical and mechanical properties of titanium carbide are caused by structure damage, multiple phase “order- disorder” transitions, and structure heterogeneity. Titanium carbide of nonstoichiometry composition was produced using the process of power SHS-compaction in the range of 0,75 < C/Ti £ 0,90. A dependence of properties of such titanium carbide on the composition (in carbon) and order degree was established. The effect of nonstoichiometry on the crystalline structure and specific electrical resistivity of titanium carbide has been studied.
Surface engineering. Multifunction films
D'yachkov V.I. Role of diffusion and interphase processes in the control of oxidation rate of titanium and its alloys
Interphase processes are found to be important in transferring from the starting period to the next one of non-stationary oxidation (T = 873¸ 1423 K) of titanium (refined and commercially pure VT1-0) and its alloys of the following compositions (in wt %): Ti–(0,6, 1,5, 2,2, 4,7, 5,9)Al; Ti–(1,9, 7,4, 14,2)Zr; Ti–2,0Al–2,5Zr (PT-7M); Ti–(1,5, 5,0, 10,0)Fe; Ti–(0,5, 0,9, 3,0)V; Ti–5,2 Al–1,2V–1,1Mo in the air and vapor-water media. The similar effect is observed in increasing temperature within certain ranges in the case of changing of the air by oxygen at T £ 1173 K (for Ti) and water vapor at T > 873(1073) K (for Ti, Ti–2,0Al–2,5Zr, Ti–5,2Al–1,2V–1,1Mo). Alloying of titanium under the considered conditions gives rise to increasing the role of diffusion in control of oxidation rate at least at T ³ 1123 K. In growing Al and Zr concentrations in the alloys the similar picture takes place in the range of T ³ 873 and 1173 K respectively, and at T < 1173 K, Zr content growth increases the role, in this concern, of interphase processes.
Energy saving and environment protection
Babkin D.G., Balasanov A.V. Calculation of gas composition during fast pyrolysis of coal in oxide melt
A pattern of gas composition calculation during rapid coal pyrolysis in oxide melt of standard characteristics according to the reference literature has been proposed. Knowledge of the composition of its dry mass as well as division of carbon between fixed and volatile one is required for determination of elementary composition of the coal-volatile matter. Oxygen, hydrogen, nitrogen, organic sulfur, and a part of carbon of combustible mass belong to the coal-volatile matter. Proposing nitrogen of the volatile matter to evolve as molecular nitrogen and sulfur of the volatile matter to evolve as elemental sulfur, a system of balance equations is made up for distribution of carbon, oxygen, and hydrogen of the volatile matter among the following compounds of CO, CO2, CH4, H2, O2, H2O, and Csoot. Carbon, oxygen, hydrogen, sulfur, and nitrogen masses of the volatile matter are input parameters and CO, CO2, CH4, H2, O2, H2O, N2 gas masses and soot carbon and sulfur masses are output parameters. The calculation results of chemical composition of the volatile matter evolving out of different coal grades during rapid coal pyrolysis in slag melt are given. Soot carbon that separates in the bath during decomposition of the coal-volatile matter of CmHn type is highly active carbon form and it can participate in combustion, reduction and other reactions along with fixed carbon, affecting coal consumption saving in the process. The pattern proposed can be used in calculation of material and thermal balances of the processes consuming coal (ROMELT, DIOS, HiSmelt, COREX, and others).
Process Control and Automation
Salikhov Z.G., Spesivtsev A.V., Shchetinin A.P., Navil'nikov E.V. On one of methods of formalizing antecedent information in studying the process of converting as an object of control
Development of correct mathematical models as one of the directions for upgrading the theory of pyrometallurgical processes is always of current important. The authors tried to carry out an investigation using “deductive” approach to the study of conversion kinetics by joining up all possible chemical reactions proceeding in the melting bath and by representing them in a formalized aspect, i.e. graph one.
