Extractive metallurgy of nonferrous metals
Samoilova O.V., Mikhailov G.G., Pashkeev I.Yu., Trofimov E.A. Transformation of nonmetallic inclusions that form in the process of interaction in copper melt containing nickel and oxygen
The thermodynamic parameters characterizing the thermodynamic features of the interacting processes in the Cu–Ni–O system under the conditions of coexistence of copper melt and condensed oxide phases have been obtained. The surface of solubility of the components in the Cu–Ni–O system metal has been plotted for temperatures of 1100–1300 °С. The composition and shape of oxide inclusions formed in the process of interaction in copper melt containing nickel and oxygen have been experimentally investigated.
Key words: copper, finishing, surface of component solubility in metal, nonmetallic compounds, nickel, oxygen.
Zvegintsev V.I., Chirkashenko V.F., Shpak S.I., Goloskin E.S., Petrov А.М. Pneumopulse system to remove deposits on inner surfaces of pneumotransport pipelines
The test results of new technology developed in ITAM SB RAS (Novosibirsk) and intended for prevention of deposition formation by periodic pneumopulse actions are submitted. Based on the analysis of the reasons of solid deposition formation on inner surface of pipelines (d = 80 mm) in the fluorinated alumina pneumotransport system into electrolytic baths at “RUSAL Sajanogorsk” JointStock Company, the test object, pneumopulsing processing conditions, and methods of its efficiency checking were determined. In accordance with laboratory and fullscale studies the cleaning system schematic was designed. The system comprises 12 impact points from which the pneumoprocessing is performed with the help of the portable smallsized pneumogenerator PG1/100. The level of initial compressed air pressure (4–5 МPа) in the pneumogenerator ensures efficient cleaning without disturbance of the main process. The tests for two and half months have shown pneumopulse processing of a tested pneumopipe segment to raise alumina feed rate by 30 % as compared with similar unprocessed segment.
Key words: pneumotransport, deposits, pneumogenerator, pneumopulse impact.
Gilderbrandt E.М., Kravtsova Е.D., Frizorger V.К. Coke particle settling simulation in the upper part of Soderberg anode
Free settling rate of coke particles in diameter from 2 to 8 mm has been measured in liquid simulating cokeoven tar pitch. It is shown that the factor is proportional to particle size and inversely proportional to viscosity of the medium. Empiric equations are proposed to estimate free and hindered settling rate of coke particles.
Key words: Soderberg anode, coke, pitch, settling rate, medium viscosity.
Extractive metallurgy of less-common and precious metals
Strizhko L.S., Normurotov R.I., Kholikulov D.B. Study of gold hydrohlorination in processing goldcontaining magnetic fraction
Hydrohlorination ensures high gold recovery into solution and allows production of highpurity metal (98–99 wt.%) according to simple schematic of its extraction out of chloride solution. High process rate results in increasing the unit capacity and accordingly in improvement of technicalandeconomic indices. Roasting of goldcontaining magnetic fraction improves the indices of gold recovery: degree of its transfer into solution from roasted fraction is 65 % and that from unroasted is 30 %. The effect of NaCl and NaClO concentrations on the gold recovery at different duration of the process is found. A process diagram of Aucontaining magnetic fraction processing with hydrohlorination is proposed.
Key words: recovery, leaching, gold, processing, magnetic fraction, chlorization, chlorination, solution, oxidizing roasting, hypochlorites, phase, chlorides.
Medvedev А.S., Bogatyryova Е.V., Pinaeva N.А. Pilot study of lowgrade molybdenite concentrate processing
The effect of lowtemperature roasting conditions of lowgrade molybdenite concentrates ([Mo] < 20 %) from different deposits and subsequent roastedproduct leaching with soda and alkali solutions to extract Mo into solution has been investigated. Based on the obtained results the expediency of soda use as a selective reagent of roastedproduct leaching is determined, roasting and leaching conditions are optimized, a flow diagram to process the indicated concentrates ensuring extraction of molybdenum into solution at the level of 87–97 % is proposed depending on the phase composition of the concentrate.
Key words: molybdenite concentrate, roasting, leaching, lowgrade raw material, processing.
Simonov Yu.А., Kritsky А.А., Rychkov V.N., Tomashov V.А. Study of MgO regeneration process from the products of its sintering with zircon
Zircon to magnesium oxide sintering process and magnesium regeneration out of magnesium chloride formed during pitch hydrochloric leaching has been studied. Thermodynamic calculations of heated equilibrium products (t = 501700 °С): MgCl2 · 6H2O and 1М ZrSiO4 + 2М MgCl2 · 6H2O have been carried out with the use of Outokumpy HSC Chemistry program for Windows. Tests on 1М ZrSiO4 + 2М MgCl2 · 6H2O mixture sintering and pitch leaching with strong HCl have been carried out to check the obtained results. The possibility of production of a mixture of associated zirconium and silicon dioxides as well as strong magnesium chloride solution is found.
Key words: zircon, zirconium dioxide, magnesium chloride, magnesium oxide, sintering, pitch, recovery, mechanical mixture of oxides.
Buslaeva Т.М., Krylova Е.А., Volchkova Е.V., Gromov S.P., Dmitrieva S.N., Sidorenko N.I. Extraction of precious metals by macrocyclic compounds. II. Extraction with crown compounds
Continuation of the review on extraction of precious metals with macrocyclic compounds is presented. The review is devoted to the extraction with crown ethers containing O, S and N donor atoms. The literary information for a period from 1984 till 2008 is generalized. It is noted that no systematic investigations on the mentioned themes have been carried so far. The information has the scattered character. The compositions of the solutions are far from technological ones, the chemical state of extracted ions in water solutions is not taken into consideration. It is underlined that there are odd bits of information related to reextraction. The problem of selectivity of extraction recovery of precious metals with crown ethers is discussed.
Key words: precious metals, crown compounds, hydrochloric solutions, extraction.
Casting production
Koltygin А.V., Bazhenov V.Е. On features of calculation of shrinkage defects in castings using ProCast program package
Using the ProCast software package, the features of shrinkage defect (cavity and porosity) formation process simulation by the example of a magnesium alloy casting are considered. The effect of some calculation parameters (MACROFS, PIPEFS, and FEEDLEN) on the results has been investigated and the recommendations for their use of different casting and alloy types are given. It is shown that the satisfactory results are obtained in most cases when correct selection of the initial simulation factors is made.
Key words: shrinkage cavities, porosity, casting process simulation, ProCast, magnesium founding, casting defects.
Powder materials and coatings
Malyshev V.V., Gab А.I. Theoretical bases and practical realization of electrometallurgical processes of producing dispersed powders and zirconium diboride coatings
Using coulometry, galvanostatic and controlled potential electrolysis, and Xray phase analysis, the electrochemical behavior of zirconium and boron, synthesis of dispersed powders and zirconium boride coatings in chloridefluoride melts have been studied. The electrochemical reduction of Zr in chloridefluoride melts is shown to have different mechanism for low and high concentrations of fluoride ions in the melt. In the first case, it takes place according to the autoinhibition scheme, and in the latter case, 4electron reversible singlestage discharge process is observed. Varying the [F–] : [Zr(IV)] ratio in the melt, one can select the conditions for realization of singlestage 4electron process of zirconium and its boride discharge. When electrometallurgical ZrB2 synthesis takes place, the discharge of electroactive particles proceeds, which are formed as a result of chemical interaction of zirconium and boroncontaining particles and different in the composition from those that are formed in partial zirconium and boroncontaining melts.
Key words: zirconium, zirconium boride, ion melt, electrochemical reduction, synthesis, dispersed powders, electroplating.
Corrosion and metal protection
Kovrov V.А., Shurov N.I., Khramov А.P., Zaikov Yu.P. Character and reasons of corrosion failure of inert anodes in the course of electrolysis of cryolitealuminous melt
The behavior of inert anodes during cryolitealuminous melt electrolysis has been investigated in laboratory electrolyzer at temperature of 960 °С. Based on electrolysis tests of more than 150 anodes of different structure and composition, the character and possible reasons of their corrosion are found. The physical and physicalchemical processes of interaction of molten electrolyte and evolved oxygen with the anode material are shown to be the basis for the phenomena of corrosion failure of the anodes. The requirements to the structure of inert anodes are formulated to increase their corrosion stability.
Key words: inert anode, aluminum electrolysis, cryolitealuminous melt, degradation of structure, corrosion.
Heat engineering and environment protection in metallurgy
Meshkov Е.I., Gerasimenko Т.Е., Kovaleva М.А. Algorithms of calculation and formation of matrices of geometrical and generalized coefficients of radiations for operating space of rotating furnace
For the purpose of the mathematic simulation with the zone method of radiation heat transfer in rotating furnace, the algorithms of calculation of angular and generalized angular coefficients of radiation and formation of their matrices have been developed. The correctness of the algorithms is supported by the fact that the radiation parameters being in accord with their property of closedness are obtained by computer calculation with their use.
Key words: rotating furnace, angular coefficient of radiation, zone method of heat transfer calculation, algorithm.
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