Mineral Processing of nonferrous metals
Ilyin V.I. Utilization of nonferrous metals out of wastewater of industrial enterprises by electrochemical method
A series of electrochemical methods has been developed for utilization of non-ferrous metals out of wastewater. Optimized were structural parameters and plant operating mode for electric processing of wastewater – electric flotation corrector providing utilization of metal cations (Cu, Ni, Zn, Cd, Cr, Fe, Al, Sn, and others) taken separately or mixed within initial concentrations of 20–300 mg/l as hydroxides as well as desalting and recovery up to 90 % of purified water for reuse in the process cycle. When purifying alkaline wastewater, 80–85 % alkali is recovered. The necessary processing time is 15- 20 min. Specific energy consumption amounts to 3,5 kWЧ h/m3 or less.
Extractive Metallurgy of Nonferrous Metals
Burylev B.P., Tsemekhman L.Sh., Miroevsky G.P. Saturated vapor pressure and enthalpy of molten copper
Based on the review of the literature data related to temperature dependence of saturated liquid copper vapor pressure and the following calculations from melting point up to 1973 K, a favorable agreement has been shown with prior measurements described by expression lgP = 10,445 – 15870 / T [Pa]. An analysis of temperature dependence of enthalpy of liquid copper allows more reliable data, which will be used for calculation of enthalpies of binary copper melts with iron group metals, to be recommended.
Begunov A.I., Yakovleva A.A., Begunova L.A., Shtelmakh S.I. Kinetic behavior of aluminum and gallium dissolution in water electrolytes
The results of gravimetric investigations of aluminum and gallium dissolution in aqueous electrolytes are given. Aluminum sulfate and hydrochloride solutions as well as the sulfuric and hydrochloric acids of the same concentrations were used. Numerical values of the kinetic parameters of metal dissolutions: rate constants, reaction orders for dissolvent, and apparent dissolution activation energies were found. Process running modes were determined: aluminum and molten gallium dissolution is determined by the convective diffusion mechanism, and solid gallium dissolution is determined by the mechanism of solid phase reaction of oxide formation.
Metallurgy of less-common and precious metals
Selection of articles in chemistry and technology of platinum metals to the memory of N.M. Sinitsyn, Professor (1931ѕ 1992)
Buslaeva T.M., Kabanova A.G., Malynov I.V., Kravchenko V.V. A role of coordination compounds in chemistry and technology of platinum metals
Studies of platinum metals complexation processes in water solutions and non-aqueous media and synthesis of individual compounds are a scientific basis for development and creation of effective processes of extraction, concentration, separation of these unique elements of the Mendeleev Periodic Table. In turn, the coordination compounds of platinum metals represent an independent interest for production of catalysts, powders, coatings, and other materials on their basis. Taking ruthenium (III) monocarbonyl chloride complexes as an example, an idea is shown about a role of coordination compounds in chemistry and technology of platinum metals. They are formed in the real processes during carbonylation of platinum-bearing materials. Pentachlorocarbonyl ruthenates (III) of general composition M2[RuCOCl5], where M is K+, NH4+, Cs+, Rb+, [Pt(NH3)4]2+, Bu4N+, have been synthesized and identified. Some applications of mentioned compounds are proposed for producing ruthenium coatings, powders of solid solutions, and catalysts of hydrosilylation reactions.
Bodnar N.M., Ezerskaya N.A., Kravchenko V.V., Pakhomova S.B., Lindt T.V. Synthesis and study of properties of osmium (II) sulfite complexes
Osmium (II) sulfite complex K10[Os(SO3)6]Ч 2H2O was produced as a result of interaction of K2[OsCl6] with K2S2O5 at 343 K. It was found by electron X-ray examination that osmium oxidation rate is +2. The results of element chemical analysis and IR spectroscopy allow us to conclude about monodentant coordination of SO32- -groups in the complex by metal ion. Based on the time change of electron spectrograms, molar electrical conduction, and pH of water solutions as well as cyclic voltamperograms of compound solutions in 0,1 mole/l H2SO4, a conclusion about sequential aquation, deprotonation, and polymerization of the sulfite complex without osmium oxidation change was drawn. Using cyclic voltamperometry and potential controlled coulometry, an opportunity of electric oxidation of osmium (II) to osmium (VI) and disproportionation of the last to osmium (IV) and osmium (VIII) was shown.
Belov S.F., Avaeva T.I., Seredina G.D. Anodic dissolution of platinum metals in acid solutions of thiocarbamide
Anodic polarization of platinum, palladium, rhodium, and iridium in the solutions containing 5–30 g/l sulfuric acid and 15–50 g/l thiocarbamide was studied. It was established that all metals have positive stationary potentials. When thiocarbamide is added to sulfuric acid solution, the metal potentials sharply move to negative area and become similar in value. It is also shown that all studied metals are anodically dissolved in sulfuric acid solutions of thiocarbamide. Increase in thiocarbamide concentration and decrease in sulfuric acid gives rise to activation of anodic processes. A comparative estimate of polarization curves allows us to conclude that the processes of anodic dissolution of metals have common mechanisms.
Belov S.F., Avaeva T.I., Seredina G.D., Kravchenko V.V. Anodic dissolution of gold in solution of sulfanic acid
Anodic polarization of gold in the solutions of sulfanic acid in the range of its concentration of 15–100 g/l was studied. Stationary metal potential is established to be practically independent on solution axidity and amounts to 0,61± 0,02 V. A great area of passive conditions is shown to be characteristic for gold. Controlled potential electrolysis conducted at different anodic potentials showed that gold dissolution rate and the form of its being in the solution is substantially dependent on the potential value. According to IR spectroscopic data, the anode product produced during electrolysis at potential of +1,75 V can be attributed to gold sulfamate Aux(NH2SO3)yЧ nH2O.
Drobot D.V., Shcheglov P.A., Seisenbaeva G.A., Kessler V.G. Rhenium oxoalkoxocomplexes as precursors for preparation of inorganic materials
Techniques have been developed to synthesize rhenium oxomethoxide and oxoisopropoxide complexes as well as rhenium bimetallic oxomethoxide complexes comprising molybdenum, tungsten, niobium, and tantalum. The techniques include electrochemical method (anodic dissolution of metals in alcohols) and interaction between rhenium oxide (VII) and alkoxide derivative of metals. The following complexes are synthesized: Re4O6- y(OMe)12+y, ReMoO2(OMe)7, Re4- xMoxO6- y(OMe)12+y, Re4- xWxO6- y(OMe)12+y, M4O2(OMe)14(ReO4)2 (M – Nb or Ta), and Re4O6(OPr-i)10. Their structures and properties including thermal decomposition behavior were studied. The data obtained permitted developing a technique to synthesize metal and oxide materials on the basis of rhenium possessing a required complex of properties (microstructure, degree of chemical and phase homogeneity).
Metal Forming
Hafercamp H., Zilberg Yu.V., Rodman M., Nimayer M., Weber I., Holzcamp U. A study of creep and friction during rolling of nonferrous metals
Creep values and friction factor were studied during rolling of samples made of magnesium, lead, and aluminum alloys using rolls with clean smooth surface, with thin coating of magnesium particles, and in presence of technological lubricant at different metal and roll temperatures. The effect of rolling rate increase from 0,13 up to 0,26 m/s and sample thickness up to 5,85 mm (at form factor 1,7) on creep and friction factor was studied.
Physical Metallurgy and Heat Treatment
Fedotov A.V. Fractographic study of powder materials on basis of iron
The results of experimental study are given for microstructure of sintered powder materials on the basis of iron. A relation between fractographic data and low crack resistance of such powder structurally heterogeneous materials at certain values of their porosity is determined and grounded.
Bokshtein B.S., Petelin A.L., Rakov S.V. Morphology and kinetic of development of liquid-metal etching grooves in the system Al- Sn
Formation and development of liquid-metal etching grooves in the system Al–Sn in a temperature range of 520–600 ° C for time periods from 20 to 150 min has been studied. Grooves of different type (mullins and nonmullins) were found. Temperature dependence of development of these grooves was studied. A range of critical wetting temperatures (540–600 ° C) was obtained. The kinetics of development of nonmullins grooves is shown to follow the parabolic law.
Powder Materials and Coatings
Kasimtsev A.V. Composite powders containing refractory nitrides
An opportunity is shown to produce composite powders, which contain refractory nitrides of transition metal, by hydride-calcium reduction of the starting charge and following internal nitriding. Taken the systems TiO2 + CaH2 and TiO2 + CaH2 + Ni as an example in conjunction with the following internal nitriding of reaction products, the mechanism of TiN and Ni–TiN alloy formation has been studied. It was established that nitriding process is to be conducted after finishing of diffusion interaction between titanium and nickel to produce the composite structure of powder particles. The data are given for some properties of composite powders of alloys containing titanium, chromium, zirconium and niobium nitrides and plasma coatings on their basis.
Structural Macrokinetics. Self-Propagating High-Temperature Synthesis
Avramchik A.N., Maksimov Yu.M., Soloviyov A.I., Malyutina V.M., Dedov N.V. Characteristics of interaction between chromium chloride and magnesium in combustion mode
The results of thermodynamic calculation and experimental study of interaction between chromium chloride and magnesium in combustion mode are given. A calculation is made for a pressure range from 0,1 up to 10 MPa for stochiometric compositions under lacking of reducing agent and its excess up to 50 %. The experiments are conducted under argon pressures from 0,1 up to 3 MPa and the reducing agent excess from 0 up to 15 % in the reducing plant. Production of metal chromium powder with content of the main substance no less than 99 % is established to be possible during interaction of CrCl3 with magnesium in the combustion mode. Macrokinetic mechanism of combustion of the composition 2CrCl3 + 3Mg comprises the first leading stage with reactions in the melt and after-combustion with gas-phase reaction at the second stage.
Soloviyov A.I., Dedov N.V., Malyutina V.M., Maksimov Yu.M., Avramchik A.N. Application of fluorides as reagents in exothermal reducing processes
Thermodynamic calculations were made and the process of calcium-thermic reduction of titanium and zirconium tetrafluorides and their mixtures was experimentally studied. Compound TiF4 and its mixture with ZrF4 in amount no more than 34,3 % were established to be reduced producing a well-formed ingot. When ZrF4 content is exceeded in the mixture to be reduced as well as during reduction of pure ZrF4 and the mixture of unseparated rare-earth metal fluorides, metal and alloys are produced as embedded particles in solidified slag. Additional heat should be brought to produce qualitative ingot during the reducing process. Qualitative ingots of metal in weight up to 10 kg were produced during calcium-thermic reduction of zirconium and rare-earth metal fluorides with application of high-frequency induction heating.
Process Control and Automation
Salikhov Z.G., Bekarevich A.A. Development of contactless automatic temperature control of calcined material lengthways rotating furnace
A method of contactless automatic control of calcined material lengthways the rotating furnace was developed. Mathematical laws binding temperatures of furnace gases and outer surface of the furnace, material calcined, and furnace gases were found. The program realizing cited above mathematical laws was developed. Experimental studies were made and temperature curves of outer surface of the furnace, furnace gases, and material calcined were obtained. Correctness of the mathematical laws was affirmed.
Khadzaragova E.A. A study of dynamic multicriterion problems for optimization of development of technologically closed system
Dynamic multicriteion problem to optimize control of development of technologically closed system is examined. Different approaches to selection of specific effective (poor-effective) solution from a majority of all effective (poor-effective) solutions are analyzed and their dynamic stability is checked.
Chronicle
Educational-and-procedural meeting of Heads of Chairs of Non-Ferrous Metallurgy from Russian Higher Schools and the Editorial Board of “Izvestia Vuzov. Tsvetnaja Metallurgia” journal
