Nonferrous ore concentration
Algebraistova N.K., Gubina E.A., Markova S.A., Ananenko K.E., Kostinenko L.P., Kuzmichyov D.V. Extraction of precious metals from return slag of affinage production
The article represents the results of laboratory tests related to metallurgical slag enrichment. The staged enrichment schemes with the use of electrical separators, jigs and flotation machines, sluices, concentration tables, and centrifugal separator Itomack were implemented. As a result, two enrichment schemes, i.e. dry and wet ones, were suggested. The schemes allow us to ensure recovery of ~95 % silver and ~89 % gold into the concentrate with overall metal content of ~15.5 %.
Extractive metallurgy of nonferrous metals
Levinsky Yu.V., Voldman G.M., Suchkova N.V., Tkachuk D.A. Method of calculation of three-phase equilibrium with gas participation in binary systems
A model has been proposed and analyzed to calculate three-phase equilibria with gas participation in binary systems. It is based on joint solution of the equations of temperature and concentration dependencies of component activity in melts and the liquidus equations on T-x-state diagrams. Comparison of the calculated and experimental data with respect to the position of - - L - G three-phase equilibrium curves on p-T-state diagrams of the Au-Cd and Cu-Zn systems confirms the acceptability of adopted assumptions and the adequacy of the model proposed. The calculation model has been used for determination of the parameters of maximum points on - - L - G three-phase equilibrium curves for some systems with metal participation.
Kirpikov A.S., Karelov S.V., Mamyachenkov S.V., Sergeev V.A. Anode oxidation of iron in cleaning zinc sulfate solutions
Investigations of anode oxidation of iron in zinc solutions have been carried out with the use of a two-chamber electrolyzer partitioned with anionite diaphragm. The positive effect of copper ions in the solution on the rate and efficiency of oxidation process is shown. The method is effective in cleaning the solutions from zinc productions and technogenic zinc-containing waste utilization.
Alkatsev M.I., Mamontova E.E., Mamontov D.V. Investigation of some regularities of oxygen-flash smelting of copper sulfide concentrates using the computer simulation method
Temperature dependence of oxygen-flash smelting of the copper sulfide concentrate on the furnace capacity, copper content in the charge and matte, the sulfur content in the charge, oxygen content in the blast and the charge humidity has been investigated. A mathematical model was offered as a result of the experiment simulation design. The mass and heat balance calculations were carried out using the designed software. Ranking of independent variables in terms of their influence degree on the slag temperature was done. The copper content in the matte and copper and sulfur content in the charge made the greatest influence (while descending).
Chekushin V.S., Oleinikova N.V., Tychenko A.I. Gold extraction from sulfide concentrates into molten lead revisited
The results of investigations related to gold recovery from sulfide minerals into melted lead under the conditions of low temperatures (350-550°С) are given. Gold solubility in Pb in the mentioned temperature range and the metal dissolution kinetics has been analyzed. Availability of the process medium to facilitate decomposition of gold-carrying minerals and to prevent oxidation of lead alloy is the principal condition of gold extraction. Alkali solution usage was proposed as such process medium. Techniques of sulfide Au-containing concentrate preparation to extraction for cake production and charge into the extraction apparatus are considered. Extraction process proceeds in the transition range. In this case, high extraction values can be reached. The reasons of collector dispersing that cause the gold losses have been found.
Vinogradov A.M., Vasyunina I.P., Mikhalev Yu.G., Polyakov P.V. Investigation of the effect of electrolyte composition on roasted anode consumption during electrolytic production of aluminum
The effect of CaF2, AlF3, and KF additives into electrolyte on the roasted anode consumption has been investigated in the course of aluminum electrolysis. CaF2 content varied from 5 to 10 wt. % in industrial electrolyte. AlF3 и KF concentrations varied from 4 to 10 % and from 0 to 4.7 % respectively in modified electrolytes. The available procedure permitted to determine general carbon consumption and quantity of carbon that has passed into the gas phase (mg) and foam (mf). Electrolysis time was 12 h, anode-to-cathode distance was 40 mm, temperature was 960°С, and current density was 0.85 and 1.2 A/cm2. It was found that CaF2 and AlF3 additives raise the anode consumption and KF additive reduces that. For CaF2, -mf/-[CaF2] is more than -mg/-[CaF2]: 15.4 and 6.6 (kg/tAl)/wt.% CaF2 respectively. For AlF3, -mf/-[AlF3] is also more than -mg/-[AlF3] and is equal to 6.8 and 4.2 (kg/tAl)/wt.% AlF3. For KF, -mf/-[KF] is less than -mg/-[KF]: -11.3 and -8.1 (kg/tAl)/wt.% KF.
Golovnykh N.V., Tupitsyn A.A., Bychinsky V.A., Zolotova A.S. Study of physico-chemical and technological properties of sodium tetrafluoroaluminate
The physical-chemical properties of condensed sodium tetrafluoroaluminate have been investigated by thermogravimetry, high-temperature X-ray phase analysis, and thermodynamic calculations of the NaF-AlF3 system state diagram. A possibility is shown to use the compound as a corrective additive of electrolyte for aluminum electrolyzers instead of cryolite and aluminum trifluoride mixture. Such replacement allows us to reduce fluoride salt consumption, optimize the balance of technological components, as well as to improve the ecology of the aluminum production.
Extractive metallurgy of less-common and precious metals
Chirkst D.E., Chistyakov A.A., Cheremisina O.V. Hydrometallurgical method of pure zinc and germanium oxide making from slag of copper-lead production
Hydrometallurgical method of copper-lead production slag processing based on sorption extraction of germanium and zinc autoclave leaching is proposed. The optimum conditions of the process have been determined. The competitive advantages of the process proposed are shown.
Casting production
Nesterov N.V., Yermilov A.G. On the effect of vacuum pressure in case of lost foam casting
Based on analysis of solution of thermal-conductivity equation during thermal destruction of model material, an investigation of liquid metal cooling has been carried out in the course of mold filling in case of lost foam casting. Metal crystallization is shown to spread from top downward, and cooling intensity grows when filling rate increases and reduced pressure in the casting box decreases. An equation is proposed for calculation of metal surface temperature; the equation accounts for the energy of thermal destruction of the model material, filling rate and initial metal temperature, reduced pressure in the casting box, and casting cross-section area in case of lost foam casting.
Materials science and heat treatment
Psaryov V.I. Analysis of Al3Mg2-precipitation dispersivity in annealing aluminum-magnesium alloys
Description of the system analysis related to the dispersed phase coarsening kinetics at the cost of Ostwald coagulation of microparticles and the accompanying processes is given. The similarity and discrepancy of experimental and theoretical distributions of microparticles by size have been carried out preliminarily for this purpose by comparison of the characteristics of distributions and concerned moments. Such a method of the distribution identification allows us to find a correlation between the features of transformation of experimental histogram distributions and the processes in a disperse system. The distribution data of Al3Mg2 microparticles by size produced after aluminum-magnesium alloy heating at 350, 400, and 430°C are a subject of the structural microanalysis.
Eskin D.G. Structural factors of dendritic segregation in aluminum alloys
The effects of cooling rate in a solidification range and dendritic structure development on the formation of nonequilibrium eutectics in Al-Cu alloys have been studied experimentally and by computer simulations. It was shown that 1D models cannot describe adequately the experimentally observed dependences, as the models do not take the development of dendritic structure during solidification into account. 2D models enable more accurate description of the solidification and the development of dendritic morphology, and as a result they allow the satisfactory prediction of dendritic segregation. It was found that the dendrite coarsening at late stages of solidification affects primarily the formation of nonequilibrium eutectics in the range of cooling rates up to 20K/s.
Economics and management
Sirotkin S.A., Kelchevskaya N.R. The problems related to using economic indices in EVA calculation
Problems of interpretation and calculation of the EVA index have been considered. The proprietary tractability of this concept is given, investigation of some approaches to the calculation of the index is carried out, and author's version of WACC calculation considering the peculiar properties of taxation load in the RF is given. In addition the principles of conversion of English indices into Russian ones are proposed.
