Nonferrous ore concentration

Panshin A.M., Yevdokimov S.I., Artyomov S.V. A new process of separation of bulk leadzinc concentrate
Based on the laboratory investigations of ore preparation characteristics and the statistical analysis of the leadzinc plant performance it is found that the production of qualitative marketable lead is possible only after crude concentrate regrinding. It is proved that flotation indicators ameliorate with a rise in metal content in the initial ore. The found dependences were used in the development of lead concentrate dezincing process for improving ore beneficiation indicators. The process concept is that the concentrate and ore are supplied for preparation of the charging material, which is crushed in ore mill and concentrated according to the direct selective flotation diagram. Improvement in quality of lead concentrate is attained at the cost of breaking down aggregates of galenite with sphalerite and pyrite. Ore beneficiation increasing can be explained by metal content rise in flotation feed and reduction in zinc/lead ratio, i.e. zinc module. Tradable characteristics obtained as a result of the industrial tests of the process of lead concentrate dezincification at the cost of reflotation with the initial ore have confirmed high efficiency of the process developed.
Key words: leadzinc concentrate, concentrate and ore charge, selective flotation of charge, sodium cyanide, zinc vitriol, dimethyldithiocarbamate, optimum consumption.

Chekanova L.G., Elchishcheva Yu.B., Shcherban’ M.G., Radushev A.V., Baigacheva E.V. Asymmetrical 1,2diacylhydrazines as reagents for ionic flotation
Physicochemical properties (solubility, acidbase equilibrium, stability to hydrolysis and oxidation, and foaming kinetics) of asymmetrical 1,2diacylhydrazines of general formulae С₆Н₅С(О)NHNHC(O)R¹, where R¹ = СН₃, C₂H₅, С₃Н₇, and СН₃C(O)NHNHC(O)R², where R² = C₇Н₁₅, C₉H₁₉, С₁₀Н₂₁, have been investigated for their flotation ability to be estimated. By the example of 1acetyl2octanoylhydrazine it has been shown that the reagents can be used for treatment of ammoniac solutions with the low metal contents from ions Cu(II), Co(II), Ni(II), Zn(II) by ionic flotation. The maximal extraction degree of metal ions at pH = 9,8 amounts to (in %): 88,0 for Cu(II), 98,0 for Co(II), 99,5 for Ni(II), and 95,0 for Zn(II). Residual concentration of metal ions corresponds to the norms of maximum permissible concentration for water to be drained into the city sewer.
Key words: ionic flotation, 1,2Diacylhydrazines, flotation reagents.

MelikGaikazyan V.I., Yemelianova N.P., Kozlov P.S. Development of methods of investigation of foam flotation from the beginning of its wide industrial application

Part one
After 100 years of industrial application of foam flotation, the followings are characteristic for it: developed practice, weak theory, inconsistent conceptualization of the process mechanism, empirical fit of reagents. To amend the situation it is recommended to use equations of capillary physics while preceding the experiments with the estimation of the optimum conditions of their carrying out. In addition, it is important to take account of the effect of capillary gas pressure on the relation of the forces acting between a bubble and a substrate (particle). The possibility of calculation of all parameters of a free bubble with a captive particle and multiple strengthening of the contact between them under the insignificant decrease of surface tension by reagents is shown. It is established that the buoyant force of a bubble does not participate in the balance of forces between a bubble and a captive particle, thus this is the necessary condition to simulate the foam flotation process in carrying out different measurements.
Key words: foam flotation, extreme event of flotation, free bubble, surface tension, capillary pressure, adhesion strengths, tearing forces, inertial tearing forces, equations of capillary physics, bubble shape coefficient.

Extractive metallurgy of nonferrous metals

Komkov A.A., Kamkin R.I. Mathematical model of impurity behavior under the conditions of reduction bubble processing of coppersmelting slag
An equilibrium thermodynamic model of lead, zinc, and arsenic behavior in the process of reduction bubble impoverishment of coppersmelting slag in the Vanyukov furnace has been developed. The effect of temperature (1250–1400 °С), oxidizing potential of the system, and quantity of the bottom phase on the impurity recovery degree into the impoverished products has been investigated. From the results of the analysis, the conclusions have been made to allow selection of optimum impoverishment mode depending on specific objectives. High recovery of arsenic into alloy particularly in increasing the quantity of the bottom phase as well as the possibility of significant zinc sublimation (> 80 %) under the conditions of deep reduction are noted. The lead distribution among phases is determined in a considerable extent by the quantity of the phase produced.
Key words: thermodynamic mathematical model, reduction impoverishment, Vanyukov furnace.

Chekushin V.S., Oleinikova N.V., Dontsov A.V. Nickel reduction from sulfides of nickel matte separation concentrate
The possibility of direct nickel reduction from its sulfides (heazlewoodite, pentlandite, disulfide) with proper sulfide sulfur in sodium hydroxide melt has been verified experimentally. The process can be realized in a temperature range of 550–700 °С with reaching 95–98 % in degree of metallization. The chemistry of sulfur disposal reaction varies depending on the duration of phase contacting (8–12 min). Sodium polysulfides decomposing in time with participation in the disproportionate reaction followed by sulfur monosulfide formation are accumulated in the alkaline fusion cake at the initial stage. The nickel reduction process from sulfides is limited by indiffusion kinetics.
Key words: nickel matte separation concentrate, nickel sulfide compounds, direct nickel reduction from sulfides, chemistry of process, kinetics, alkali consumption, oxidation processes.

Frizorger V.K., Gildebrandt E.M., Vershinina E.P. Soderberg anode quality monitoring in aluminum electrolyzers with top current lead
The distribution of physical properties with anode height, including when temperature varying, has been studied by core sampling from Soderberg anodes of the disconnected aluminum electrolyzers. An analysis of the anode quality history from 1993 to 2006 is given. It is shown that the physical properties of Soderberg anode are close to the requirements imposed to baked anodes.
Key words: Soderberg anode, cores, physical properties, anode quality, carbon consumption.

Bazhenov A.A., Miklushevsky V.V., Vatulin I.I., Kropachyova E.N., Bidylo A.P. Investigation of lithium carbonate dissociation process above aluminum powder
The results of the lithium carbonate dissociation process research over aluminum powder in vacuum are given. It has been found that the dissociation degree reaches ~ 60 % at the process temperature of 700 °С, and the thermal breakdown of lithium carbonate slows down. It follows from the Li₂CO₃–Li₂O equilibrium diagram that the raise of temperature results in liquid phase formation. Based on the experimental data and using the bisection method, the maximum heating rate from 700 to 740 °С being equal to 0,33±0,02 °С/min has been determined at which no formation of lowmelting eutectics between lithium carbonate and oxide takes place. In such a case, the partial microfusion does not affect the mechanical properties of briquette. The matched temperature mode provides uniform thermal lithium carbonate breakdown throughout the briquette mass, thus minimizing a possibility of contacts between lithium carbonate and oxide. Under such conditions, time of full dissociation degree is 2 h. Decrease in heating rate results in increase of the duration of dissociation process and increase in heating rate does to briquette surface melting. Aluminum at the dissociation stage plays the role of inert addition that accelerates the dissociation process.
Key words: lithium carbonate, aluminum powder, dissociation, bisection method, thermodynamic analysis, Yerofeev–Kolmogorov equation, hightemperature vacuum plant.

Extractive metallurgy of less-common and precious metals

Denisov V.M., Denisova L.T., Osipovich T.V., Kirik S.D. The effect of silver on Ge–Bi melts oxidation
The kinetics of (Ge–Bi) + Ag melt oxidation has been investigated depending on melt composition by hightemperature gravimetric analysis in the air at temperature of 1273 К. Introduction of silver into the Ge–Bi melts is found to vary both their oxidation rates and the scale composition formed.
Keywords: oxidation, melts, silver, germanium, bismuth.

Casting production

Nesterov N.V., Yermilov A.G. Mathematical model of mould filling kinetics in cavityless casting
Form fillout during cavityless casting has been investigated on the basis of analysis of foamedpolystyrene thermaldestruction product flows. A mathematical model of the process has been developed that is based on the displacement of gaseous products formed as a result of foamedpolystyrene thermal destruction from the gasification zone of a mould with excess pressure in the gas gap between foamed polystyrene and molted metal. A comparison of the calculation data with the available experimental data on time dependence of pressure in the gas gap and the measurement of time duration of real casting has been carried out. Satisfactory similarity of the calculation dependences and indices with empirical ones is noted. The formulas to calculate pressure, which determines the mould stability and the conditions of nondefective casting production, in the thermal destruction zone as well as the method of computation of mould fill time are proposed.
Key words: cavityless casting, thermal destruction, mould porosity, pressure, mould fill time.

Metal forming

Biyakaeva N.T. Investigation of regularities in metal structure behavior in expansion of specimen
The article investigates the effect of linear stretch on the structure and property of metals and alloys. The technological opportunities of recrystallization process activation and grain growth averting with a view of the effective structure refining are considered.
Key words: plastic deformation, linear stretch, degree of reduction, titanium alloy, metal structure, tensile stress, recrystallization.

Maksimov E.A. Determination of stressdeformed state and flatness parameter in bending wavelike section of strip in plate rolling of brass sheets and bands
Dependences are presented for calculation of the stressdeformed state arising in bending on a wavelike site of a strip in the plastic range. The expressions for determination of tangential and radial stresses consider the strip and tape hardening taking place in the plastic bending. With allowance for the continuance condition of secondperiod volumes and change of nonuniformity of longitudinal metal velocity across the width of a strip in the plane of roller exit, the dependence for calculation of the flatness parameter is derived in bending a wavelike site of a strip in the plastic range.
Key words: ridge buckle, plastic bending, stressdeformed state, waviness parameter.