Computer simulation of multicomponent melts of metallurgical slags

E. V. Dyul’dina, B. R. Gelchinski, V. N. Selivanov

ABSTRACT

Based on the experimental data on the density, the molecular dynamics simulation of multicomponent oxide-fluoride metallurgical slagFforming systems: SiO2–CaO–Al2O3–MgO–CaF2–Na2O–K2O–FeO was carried out for the first time in the approximation of the ionic bond model. The results were discussed and compared with literary experimental and calculated data. The obtained model indicates a weak temperature dependence of the structure of the melt. An increased diffusion mobility of fluorine ions as well as ions of alkali metals in comparison with other elements has been revealed.

KEYWORDS

melt, metallurgical slag, computer simulation, structure, properties

On the motion nature of the atoms in metallic melt

N. P. Uglev, S. N. Uglev

ABSTRACT

The paper analyzes the experiments on metal melt stratification in inclined zigzag capillaries with a mechanical potential barrier preventing the through movement of clusters or microcrystals of metals, in comparison with similar processes in the direct inclined capillary. It is shown that in the transition to a complex capillary with a potential barrier of greater height, the penetration of individual atoms through the barrier almost completely stops. The comparative analysis of the velocities of the processes of capillary stratification and diffusion, as well as the influence of temperature on them, performed within the framework of the previously proposed model of liquid metal in the form of an ultra-colloidal system of solid particles separated by a monoatomic layer of super-fluid atoms, in conjunction with the results of other experiments, allows us to conclude that there are no continuous mechanical oscillations of atoms in the field of interaction potentials. The particle system, in both solid and liquid States, is a degenerate Bose condensate. The mechanisms of energy storage and melting in such a system, as well as diffusion and capillary stratification processes in metal melts are proposed.

KEYWORDS: stratification, inclined capillary, zig-zag capillary, coiled capillary, a metal melt, barometric distribution, diffusion, super fluidity in the melts

Thermodynamic modeling of melts of the semiconductor systems AIII–BV

N. I. Ilinykh, I. A. Malkova

ABSTRACT

In this paper, the equilibrium composition and thermodynamic characteristics of Ga–Sb, Al–Sb, and In–Sb binary melts were studied in a wide range of temperatures and compositions using the thermodynamic modeling method and the TERRA software. The investigation of temperature dependences of the partial pressures of the gas phase components formed above the melts of the AIIIBV system, where AIII–Ga, In, Al; BV–Sb was carried out. Concentration dependences of the activity content of the components, partial and integral melting characteristics of the melts have been constructed. It is shown that large negative deviations from the Raoult law are observed for all the melts studied. This fact is due to the presence of associates and indicates a strong interaction between the components of the melt. The temperature dependences of the logarithms of the partial pressures of the components of the gas phase are constructed. It is shown that for the components of the gas phase formed above the Ga–Sb, Al–Sb, and In–Sb melts, these dependences are linear.

KEYWORDS:: semiconductor materials, gallium, antimony, aluminum, indium, thermodynamic modeling, melt, gas phase, properties

Analysis of kinetics of germany and mass crystallization of reduced melt in accordance with thermo-graphics of fleecibility

V. D. Aleksandrov, A. P. Zozulya, A. Yu. Sobolev

ABSTRACT

Based on the information obtained during the decoding of the thermograms of heating and cooling of simple substances, the cluster-coagulation model of supercooled melts crystallization has been further developed. Three successive stages of solidification are described in detail: nucleation, coagulation of nucleus and isothermal crystallization. Equations are proposed for calculating the various kinetic and thermodynamic parameters of crystallization (temperature and melting enthalpy and crystallization, incubation period of a new phase nucleation, degree of pre-crystallization supercooling, time and velocity of explosive crystallization, time and velocities of phase transformations etc.). Using the characteristics of the crystallization process found using thermograms, the critical dimensions of the crystal nuclei and the work of their formation, the degree of crystallinity, the nucleation constants and the Avrami parameters, the energy of coagulation of the nucleus, the isothermal precrystallization constants etc.

KEYWORDS:

crystallization, melting, nucleation, thermal analysis, thermogram, supercooling, tin.

Mathematical description of the oxidative refining of molten blister copper

V. P. Zhukov, S. I. Holod, V. G. Lisienko.

ABSTRACT:

Anode melting of blister copper based partial removal of impurities with a having high affinity for oxygen. The centralized process of refining one plant is complicated by the different and variable chemical compositions of the charge of blister copper supplied by different factories – producers. Therefore, is constantly changing, the weighted average composition of the liquid metal depending on each load, therefore requiring a different amount of oxygen for oxidation and slagging. The aim of this work is to develop a methodology for calculating a theoretically required oxygen concentration in the melt of the mass, (t): Cu2O as the target function of the mass of the impurity of blister copper.

Using the method of regression analysis, we developed a mathematical model approximating function O2 = f(Cu2O), which can be used to quickly calculate the concentration of oxygen supplied to the melt oxidation stage of fire refining. The results revealed of the regularities built a graph dependencies of the concentration of oxygen in the melt by mass of copper oxide (1).

Mathematical description is made on the basis of the average composition of the mixture from four factories – producers.

The algorithm model is built based on passive experiment, with the selected assumptions and limitations.

It is established that the described algorithm with the use of MLS on the platform applied Microsoft Excel and the stoichiometric oxidation reactions of impurities shows a linear dependence of the concentration of oxygen supplied to the melt by mass of copper oxide (1), indicating the adequacy of the obtained model.

KEY WORDS:

Mathematical model, oxygen concentration, impurity concentration, charge, fire refining

Influence of the content of fluorine in alkaline on the indicators of aluminum electrolysers of the Kazakhstan electrolysis factory

Zh. Zh. Kamzin, V. A. Lebedev

ABSTRACT:

For two series of electrolysis, a regression analysis of the dependences of the average voltage, current yield, specific power consumption on the fluorine content in fluorinated alumina (CF), received for electrolysis, was performed. An increase in CF by 1% is accompanied by a slight increase in average voltage (5–10 mV), a significant (by 0.5–1.1%) reduction in current output and an increase (by 110–170 kW h/t) in the specific consumption of electricity. To improve the electrolysis, it is necessary to lower the fluorine content in fluorinated alumina.

KEY WORDS:

fluorinated alumina, fluorine content, average voltage, current efficiency, specific power consumption, regression analysis.

Observation of the structural transition L12 → FCС in small nanoclusters Cu3Au

Yu. Ya. Gafner, S. L. Gafner, L. V. Redel, I. S. Zamulin

ABSTRACT:

It is known that Cu3Au alloy nanoparticles are widely used in the catalysis of a wide variety of chemical reactions, since it has been experimentally determined that partial gold substitution of copper in many cases leads to an increase in catalytic activity. However, the surface electronic structure responsible for the reactivity of the alloy nanoparticles strongly depends on the atomic ordering in them. Therefore, to determine the catalytic properties theoretically, it is necessary to use the most real structural model corresponding to Cu3Au nanoparticles under the condition of various external influences. Based on this, the boundaries of thermal stability of the initial L12 phase in clusters of nano_alloy Cu3Au with a size of up to 8.0 nm were investigated by the molecular dynamics method using the modified tight binding potential TB_SMA. It is shown that under the influence of the temperature factor in Cu3Au clusters fcc is possible a structural transition L12 → FCC. It is concluded that, unlike macroscopic bodies in nanoparticles this transition occupies a wide temperature range.

KEY WORDS:

nanoalloy, structure, computer simulation, tight binding

Electronic spectra of mixtures xNa2O–(100 – x)B2O3 and xNa2O–(100 – x)B2O3–Re2O3. (Re = Sm, Eu)

A. A. Khokhryakov, A. O. Vershinin, A. S. Paivin, S. A. Istomin

ABSTRACT:

The molten mixtures of xNa2O–(100 – x)B2O3 and xNa2O–Re2O3–(100 – x) B2O3 (Re = Sm, Eu), where x is a mole % Na2O, were studied by electron spectroscopy. In these mixtures, as the concentration of sodium oxide increases, cyclic changes in the coordination numbers of boron atoms are found. The selected minima on the “concentration of the BO4/2_concentration of sodium oxide” groupings have a different origin. The rupture of the boron-oxygen network of the melt xNa2O–(100 – x)B2O3 occurs at x > 40, and in ternary borate mixtures at x > 30. It is assumed that the coding numbers of samarium and europium ions increase from 6 to 8 in the interval 0 < x <10 and remain constant for x > 10.

KEY WORDS:

boron anomaly, electronic spectra, borate melt, rare earth elements, polycationic effect.

Study wear resistance at high temperatures of thick aluminum oxide as a protective coating on aluminum crystallizer continuous casting machine

A. V. Nechayev, L. N. Kodomskoy, E. V. Nikinina

ABSTRACT:

Presented results of measurement of microhardness wettability thick aluminum coating liquid steel, the stability of these coatings to abrasion at high temperatures under dry friction. The problem of finding optimal conditions for thick_film deposition of aluminum oxide coatings with maximum wear resistance and microhardness was solved by a method of mathematical planning of the experiment. optimal conditions for electrolysis, providing the most wear-resistant coatings poluchennyz were selected on the basis of mathematical planning. Obtained under optimal conditions electrolysis oxide coatings were tested for abrasion at high temperatures under dry friction.

KEY WORDS:

aluminum alloys, thick oxide coatings, wetting liquid steel, micro-hardness, wear resistance at high temperatures.

Investigation of the minimum interatomic distance in liquid metals based on acoustic data

V. V. Tekuchev, D. P. Kalinkin, I. V. Ivanova, A. V. Arshinov

ABSTRACT:

Within the framework of the statistical theory, hard_sphere models for the first time, based on ultrasound velocity data, determine the shortest interatomic distance of 24 metals from the melting point to the boiling point. With increasing temperature, the diameter of hard spheres (the minimum interatomic distance) decreases linearly. The polytherms of the interatomic distance for liquid metals are also valid for the solid phase.

KEY WORDS:

metals, ultrasound velocity, diameter of hard spheres, minimum interatomic distance.