Metallurgy of nonferrous metals
Selivanov E.N., Sergeeva S.V., Udoeva L.Yu. Specific properties of reduction of high-magnesia nickel ore from the Serovsky deposit
The parameters of reducing roasting of high-magnesia oxide nickel ore containing (in wt.%): 1,2 Ni, 0,026 Co, 17,0 Fe2O3, 4,0 Al2O3, 20,2 MgO and 46,0 SiO2 have been estimated. Reduction and metallization degrees in heating ore with reducing agent at t = 800¸1250 °С and dimensions of metallic inclusions, which are formed in the course of the process, are determi-ned. For the purpose of phase disengagement, magnetic separation is used at H = 40 and 80 kA/m. The best results are reached in roasting ore with reducing and sulfidizing agents at t = 1300 °С. In this case the magnetic fraction contains 7,1 % Ni and nonmagnetic one does 0,18 % Ni.
Key words: nickel ore, reduction, magnetic separation, roasting, extraction.
Kochin V.A., Khrennikov A.A., Lebed’ A.B., Naboichenko S.S. Regularities in sulphation of lead sulfide as a part of Cu–Zn–Pb concentrate
The chemical and phase compositions of Cu–Zn–Pb-concentrates from Rubtsovsk Concentrating Mill and products of their sulfuric acid processing under Fe2(SO4)3 oxidizer have been investigated. The natural galena sulphation in acidified Fe(III) solutions is shown to proceed in the kinetic range in the initial period and then it is limited by diffusion. The found regularities of the galena sulphation were supported in leaching concentrate from the Rubtsovsk deposit under the same conditions. The data for the product composition and yield are given.
Key words: lead sulfide, galena, zinc sulfide, sulfide concentrate, leaching, sulphation.
Vasyunina N.V., Vasyunina I.P., Mikhalev Yu.G., Vinogradov A.M. The behavior of secondary alumina in its heating
Weight and fluorine-containing compounds losses with secondary alumina at different temperatures of 80, 100, 200, 300, 400 °C, which can be reached in an automatic alumina feeding bin, have been estimated. The fluorine content in alumina after heating after its holding at a given predetermined temperature was analyzed by photocolorimetry. In heating secondary alumina at temperature t > 80 °C, there observed significant mass and fluorine losses in it, being connected with removal of fluorine with physically adsorbed moisture. The major portion of fluorine however remains even at t = 400 °C inasmuch as it constitutes solid fluorides and chemisorbed particles. Fluorine desorption out of alumina at relatively low temperatures (beginning at 80 °C) means the necessity of constructive and technological measures for temperature decrease in automatic alumina feeding bins.
Key words: aluminum electrowinning, dry gas cleaning, secondary alumina, fluorinated alumina, fluorine content determination, adsorption model, weight losses.
Extractive metallurgy of less-common and precious metals
Knyazkina O.V., Kuznetsova G.G., Travkin V.F., Voldman G.M., Glubokov Yu.M. Extraction of molybdenum with bis(2,4,4-trimethylpentyle)phosphine acid (Cyanex-272)
The effect of different parameters on recovery of molybdenum by extraction with bis(2,4,4-trimethylpentyle)phosphine acid (Cyanex-272) has been considered. It is found that its maximum value is reached at рН ~2. Using the saturation and equilibrium shift methods, Cyanex-272 is shown to extract Mo from chloride, nitrate, and sulfate solutions according to the cation exchange mechanism with bonding two single-charged acid residuals of dimmer of bis(2,4,4-trimethylpentyle)phosphine acid to Mo cation. Based on the results obtained by UV- and IR-spectroscopy, the structure of extractable molybdenum compound is determined and it is shown that it is similar to the structure of substances formed during extraction by other organophosphorus acids.
Key words: molybdenum, extraction, bis(2,4,4-trimethylpentyle)phosphine acid, recovery.
Buslaeva T.M., Krylova E.A., Volchkova E.V., Gromov S.P., Sidorenko N.I. Extraction of precious metals with macrocyclic compounds. III. Extraction with calixarenes
The third conclusive part of the review on extraction of precious metals by macrocyclic compounds is presented. It is devoted to extraction by O-, S-, and N-containing calixarenes. The part generalizes also the literary data from 1978 to 2008. It is noticed that systematic studies on extraction of precious metals by calixarenes have not been carried out. The majority of works are qualitative and consider no regularities of the effect of water and organic phase compositions, the properties of extracting agents on the metal recovery degree. The solutions under investigation are far in composition from the process ones. The chemical condition of recoverable ions in water solutions is not considered sometimes. It is emphasized that the literature has piecemeal information on re-extraction. The selectivity problem of precious metal extraction recovery with crown ethers is discussed.
Key words: precious metals, calixarenes, hydrochloric acid solutions, extraction, re-extraction.
Gudkov A.S., Zhuchkov I.A., Mineev G.G. Estimate of autoclave oxidation of sulfide concentrates as applied to the following sulfite-thiosufate leaching of precious metals
Investigations of the sulphite-thiosulfate precious metal dissolution efficiency under the conditions of autoclave decomposition of flotation concentrates under different leaching conditions (reagent concentration and the effect of various additives) are described. The necessity of autoclave decomposition process is shown that provides maximum recovery with cyaniding in view of considering the factors increasing the elemental sulfur content in autoclave decomposition cake.
Key words: sodium sulfite, sodium thiosulfate, sulfite leaching, non-cyanic dissolvents of gold, cake leaching, autoclave decomposition, elemental sulfur content.
Materials science and heat treatment
Solonin A.N., Churyumov A.Yu., Mikhailovskaya A.V., Ryazantseva M.A., Khomutov M.G. Simulation structure and property evolution of the Al–Zn–Mg system during aging
Investigation and modeling of artificial aging in alloys of the Al–Zn–Mg system have been carried out. Transmission electron microscopy, electric resistance measurement at elevated temperature and differential scanning calorimetry were used to determine the kinetic parameters of supersaturated solid solution decomposition. To describe the structure evolution in the aging process the Avrami equation and the aging time dependence of particle size were used. Comparison between calculated and experimental values of particle size showed sufficiently high accuracy of the model. On its basis, the yield strength of alloys in the aged condition have been calculated. The computational error was 11 %, being comparable with the error of experimental determination of yield strength.
Key words: aluminum alloys, artificial aging, Al–Zn–Mg system, modeling, yield strength, structure evolution.
Yemelina N.B., Alabin A.N., Belov N.A. The effect of bismuth and lead on structural formation of experimental alloys on the basis of Cu–30%Zn composition during crystallization, deformation, and heat treatment
The effect of annealing (t = 600 °C) on the microstructure of cold rolled L70 brass with additives of bismuth and lead in quantity from 0,001 to 1 % has been investigated. Size of recrystallization grain is shown not to depend practically on these additives, and Bi- and Pb-containing phases are arranged predominantly along the grain boundaries and have spherical shape.
Key words: cold rolling, L70 brass, bismuth, lead, microstructure, casting, homogenized annealing, recrystallization annealing.
Powder materials and coatings
Blinkov I.V., Tsaryova S.G., Zelentseva A.V., Volkhonsky A.O., Buzanov V.I., Steparyova N.N. Structure and phase formation in generation of nanostructural ion-plasma Ti–Cr–Al–N coatings on cutting cemented carbide tools
The possibility is shown to apply nanostructural Ti–Al–Cr–N coatings onto cutting cemented carbide tools with crystallite size of 20–60nm by ion-plasma arc deposition with the use of cathode spraying system and separation of plasma flows from drop phase. The regularities of structural and phase formation in the coating material are established depending on the bias potential being supplied to a substrate (U = –100¸–160 V) and determining the energy of sprayed particles and the condensation point as well as on spraying arc current on the chromium cathode (ICr = 90¸130 А) and its dependent chromium concentration in vapor phase and the coating being formed.
Key words: ion-plasma arc deposition, coatings, structural and phase formation in the Ti–Cr–Al–N system, crystallite size, microdeformations.
Gostishchev V.V., Ry Kh., Khimukhin S.N., Ry E.Kh., Komkov V.G. Production of molybdenum powder with metallothermy of its compounds in sodium chloride melt
The conditions of molybdenum oxygen compound reduction to metal powder with aluminum and magnesium in sodium chloride melt have been studied. The thermodynamic estimation of reduction reaction is given. It is found that it is necessary to use 30 % excess of the reducer amount as compared to the designed one to provide 95–97 % of powder yield; in this case the amount of impurity elements in reduction products does not exceed 3 %. The effect of production conditions on granulometric powder parameters has been established. Powders with the greatest specific surface (64,4·105 м–1) are shown to be formed when using aluminum in concentrated solutions of mother compound in NaCl melt.
Key words: molybdenum powders, molten salts, aluminum, magnesium, reduction.
Process control and automation
Zarochentsev V.M., Rutkovsky A.L., Bolotaeva I.I. Model for current yield determination during electrolytic deposition of zinc from sulfate solutions
A hypothesis of two mechanisms of cathodic reaction is formulated. A mathematical model of the current output on the cathode is developed for zinc electrolytic deposition from sulfate solutions. The model can be used for designing and technological calculations of the parameters for zinc hydrometallurgical production processes. An analysis of the simulation results for the estimation of the effect of solution component concentration and current density on process indicators has been carried out. Characterized by high current output, the parameter space has been chosen.
Keywords: electrolysis, cathode reaction, zinc, sulfate, electrolyte, model, current yield.
Economics and management
Kulchitsky N.A., Naumov A.V. The state of the markets of cadmium, tellurium, and compounds on their basis
A survey of world’s lithium market development is made. Post-crisis perspectives are under consideration. The current state and development prospects of Russian lithium industry are analyzed.
Key words: Li minerals, brines, demand, proposal, production capacity, post-crisis prospects
