Extractive metallurgy of nonferrous metals
Naguman P.N. Chemistry and kinetics of oxidized copper sulphidation by sodium thiosulphate
Researches of the conditions of copper sulfide formation as a result of interaction between sodium thiosulphate and oxidized copper compounds have been carried out. The effect of such factors as precipitator consumption, acidity, temperature on this process has been studied. It has been found that copper can be extracted quantitatively from the solutions by sodium thiosulphate in the form of covelline and chalcosine. The kinetics of interaction between Na2S2О3 sodium thiosulphate and oxidized copper compounds in a temperature range of 40 to 100 °C with consumption of 1,5 moles of Na2S2O3 per one mole of the metal extracted has been studied. Equations describing typical kinetic curves of sulphidation have been selected. The constants of reactions speed are calculated.
Chuikin A.Yu., Zaikov Yu.P., Beketov A.R. Interaction of highalumina concrete with lowtemperature potassium cryolite based melt
Using gravimetric analysis, the kinetics of interaction of variouscomposition highalumina concrete with lowtemperature fluoride melt KF–AlF3 in a temperature range of 700–800 °С has been studied. Such an analysis allows us to oversee, in the course of the experiment, the mass variation of investigated material placed in fused salt mixture and to calculate the loss rate. The interaction of concrete binding component with the melt, the nature and kinetics of which are affected by the concentration of dissolved Al2O3, melt temperature, and preliminary heat treatment of concrete, was found as a result of the researches conducted. The samples remained unchanged in the shape and dimensions after the experiments with alumina saturated melt (5 wt% Al2O3, T = 700 °C). They suffer corrosion when the alumina content in the melt is less than 2,5 wt%. A possibility is shown to apply highalumina concrete as structural material of electrolysis baths in case of transfer to potassium cryolite in the future.
Isaeva L.A., Braslavsky A.B., Polyakov P.V. Rising of dust and fluidity of alumina with different physicalchemical properties
The subject of researches is metallurgical alumina from various manufacturers and with different physicalchemical properties that vary within a wide range: –45 µm fraction content is 460 %, ignition losses are 0,51,2 %, phase content is 2,523 %, and specific surface is 55–120 m2/g. The flow time (tf) of alumina was measured using orifices with standard (2,4 mm) and oversize (4 and 5 mm) holes and it amounted to 2–20 min. Correlations between tf for orifices with above mentioned holes have been obtained. The flow time decreases depending on –45 µm fraction quantity becoming lesser and growing moisture content in alumina. Risingofdust index (RI) was measured using a manufactured dust counter; its variability interval was 0,5–8 mg/g. The RI value grows with increase of –45 µm fraction quantity and moisture in alumina. The grainsize composition is the crucial factor determining tf and RI. The effect of its particle shape and availability of moisture in it on tf and RI has been found. A mechanism explaining the interrelation of moisture with these values has been proposed.
Gildebrandt E.M., Frizorger V.K., Vershinina E.P., Kravtsova E.D. Viscosity of coke and cokepitch mixtures
Using oscillatory viscometer at T = 430750 K, viscosity of three coaltar pitches (softening points are 361, 386, and 393 К) and dustpitch mixtures containing fine fraction (–0,074 mm) of calcined oil coke in quantity of 15, 30, and 50 % has been measured. The characteristics of viscous flow of these materials have been determined from the results of the researches, thus drawing a number of practical conclusions useful for the aluminum industry.
Extractive metallurgy of less-common and precious metals
Buslaeva T.M., Krylova E.A., Volchkova E.V., Gromov S.P., Sidorenko N.I. Precious metal extraction by macrocyclic compounds
A review of the literature concerning the precious metal (PM) extraction by acyclic analogues of crown ethers – podands for a period from 1980 through 2007 is presented. The emphasis is on the PM extraction by phosphoryl containing podands from hydrochloride solutions. A conclusion is drawn that the main factors affecting its efficiency are number and character of donor centers in reagent molecule. Application of podands as PM extraction agents is shown not to allow us to solve the problem of selective PM extraction from the solutions of complex composition.
Metal forming
Bitkov V.V. Calculation of redundant deformation factor during nonferrous wire drawing
Accompanied by localized plastic shear deformation and tension, axisymmetric wire drawing through conical die channel results in deformation discontinuity both in longitudinal and cross sections of workable metal. The redundant deformation factor, which is determined analytically or from experimental measurements of microhardness distribution across the section of great diameter nonferrous wires or round bars, is used for its analysis. Using В. Avitzur solution worked out by the upper bound method on the basis of kinematically possible trapezoidal and spherical velocity field, an expression has been derived for calculation of the redundant deformation factor. An analysis of the effect of the geometrical parameter on the deformation discontinuity in the course of wire drawing has been carried out. The design and experimental data have been compared by the example of copper wire drawing.
Powder materials and coatings
Kasimtsev A.V., Zhigunov V.V. Mechanism and kinetics of monocrystal titanium carbide powders by hydridecalcium method
The mechanism and kinetics of reduction–carbonization of titanium oxide by calcium hydride and carbide (hydridecalcium method) to produce monocrystal titanium carbide powders have been studied. The theoretical analysis and experimental techniques have ascertained that TiC formation mechanism is of stage character and consists of two successive reactions: TiO2 + 2CaH2 = Ti + 2CaO + 2H2 and Тi + C = TiC. It has been found that titanium carbide formation takes place in calcium melt by titanium and graphite dissolution in it followed by crystallization of TiC particles from the melt. It is noted that the process kinetics in a range of t = 9001200 °С is dependant of isothermal holding temperature and time. Its pronounced activation at t >1100 °С takes place at the cost of increase of calcium based melt amount and titanium and carbon solubility improving in it, thus resulting in acceleration of reactions of titanium oxide reduction to titanium and titanium carbide synthesis. The optimal process parameters: temperatures, isothermal holding time, conditions of charge calculation have been determined. The titanium carbide produced according to the given process is shown to be homogeneous and be of the composition close to the stoichiometric one TiC1,0.
Heat engineering and environment protection in metallurgy
Shchyolokov Ya.M. Improvement of the design of cyclone dustcatching apparatuses
A range of dust particlesize distribution is determined when the reconstruction of cyclone apparatuses is advisable for the purpose of increase in the dustcatching efficiency.
Process control and automation
Velt I.D., Mikhailova Yu.V. Measurement of metal containing mass of pulp products by electromagnetic method
Two methods of solving the problem of highprecision measurement of metalcontaining pulp mass are considered. The first one consists in continuous measurement of magnetic permeability of pulp and automatic introduction of an allowance in calculating dry mass of metalcontaining product; the second one provides application of special electromagnetic flow rate meters insensitive to magnetic property change of the medium to be measured. The engineering solutions that allow us to produce an electrical signal characterizing the magnetic permeability of pulp are analyzed. Its availability gives a possibility not only to eliminate a measurement error of volume flow rate caused by the effect of magnetic component of pulp but to measure the metalcontaining product mass. The use of such electromagnetic flow meters is the most promising way to solve the problem formulated.
Economics and management
Sirotkin S.A., Kelchevskaya N.R. Use of incremental method in calculation of the effect of capital investments
The incremental method has been used for calculation of the effect of capital investments. The author’s technique to determine the economic effect using the incremental method with taking the characteristic properties of taxation in the RF into account is proposed, and an example of calculating the integral economic effect and the payoff period of a project with its using is given.
Standards and regulations
Karetnikova N.V. Why the technical regulation system is not regulated in the RF
Chronicle
To the 90th birthday of Sergey Ivanovich Kuznetsov
To the 75thyear anniversary of Vladimir Georgievich Lisienko
