Dynamics of cluster structure change in melts that forms a continuous series of solid solutions during equilibrium and nonequilibrium crystallization

V. D. Aleksandrov, S. A. Frolova, A. P. Zozulya

ABSTRACT

The scheme of a cluster structure of melts that forms a continuous series of solid solutions in the overheated and overcooled states concerning liquidus temperatures is developed. Structure change dynamics of clusterized liquid during cooling and further equilibrium and nonequilibrium crystallization is analyzed. Coexistence areas of liquid solution with clusters, nucleus and a solid phase are designated. Borders of a clustering and a way of their transformation to nucleus and crystals of solid solutions are defined. The thermograms of cooling characterizing different types of crystallization of alloys are considered. On their basis the analysis of ways of crystallization according to state diagram is given.

KEYWORDS

melts, binary system, alloys, solid solutions, state diagram, solubility, entropy, clusters, clustering, nucleus, equilibrium and nonequilibrium crystallization, thermograms

DOI: 10.1134/S0235010619030034

Thermal researches of the process of obtaining magnesium master alloy with ittrium and zinc

S. А. Savchenkov, V. Yu. Bazhin, V. N. Brichkin, V. L. Ugolkov

ABSTRACT

Using thermal analysis (DTA), processes occurring during the interaction of yttrium fluoride melts with sodium fluoride and potassium chloride, used as a flux in the metallothermic synthesis of the Mg–Y master alloy, were investigated. In addition, to identify patterns of magnesium thermal reduction of yttrium from the salt mixture, thermal studies of the interaction of yttrium and sodium fluoride salt systems and potassium and sodium chlorides with magnesium and zinc were carried out.

KEYWORDS

magnesium master alloy, master alloy magnesium–zinc–yttrium, thermal analysis, magnesium thermal reduction, synthesis

DOI: 10.1134/S0235010619030095

Influence of weather conditions on aluminum work indicators of electrolysis of Kazakhstan electrolysis factory

V. A. Lebedev, Zh. Zh. Kamzin

ABSTRACT

According to the average monthly data of OA “KEZ” from January 2010 until March 2011 for two series of electrolysis, working at the plant, a regression analysis of the dependences of the average voltage, current yield, specific consumption of electricity from the water vapor pressure in atmospheric air (P) was performed. Increase in P by 10 mm Hg does not affect the amount of working interference, increases the current efficiency by 0.48– 0.63%, reduces the specific power consumption by 73–78 kW • h/t. The observed regularities are explained by a decrease in the fluorine content in flowing into the cryolite-alumina melt of alumina by the removal of desorbed hydrogen fluoride with water vapor in the presence of fluorinated alumina in the range of APG punching.

KEYWORDS:

fluorinated alumina, fluorine content, water vapor pressure, average voltage, current efficiency, specific power consumption, regression analysis

DOI: 10.1134/S0235010619020026

High-temperature calorimetric research of CaO–MgO–Al2O3–SiO2 slags

A. Korytseva, A. Navrotski

ABSTRACT

The enthalpy of dissolving slag-forming oxides in slag CaO–SiO2–Al2O3–MgO at 1450 C was measured by drop-calorimetry. The enthalpy of dissolution becomes more exothermic in the order of Fe2O3, MgO, Al2O3, CaO, SiO2, which reflects the relatively basic nature of this slag with a low silica content. The observed trends are consistent with the available other melts, while the observed differences in the values reflect differences in the acid-alkaline character of the melts. The obtained results give reliable data for the future modeling of the thermal balance of both steelmaking furnaces and various processes in geological and ceramic systems.

KEYWORDS:

calorimetry, slag, enthalpy, iron oxide, aluminum oxide, silicon oxide

DOI: 10.1134/S0235010619010092

Mesoscopic model for a metal vapor condensation

A. E. Korenchenko, A. G. Vorontsov, B. R. Gelchinski

ABSTRACT

We consider a way to transfer data from molecular dynamic simulation of metal vapor condensation to partial differential equations of continuous medium. To simulate condensation in mesoscale model we suppose that the chemical mixture changes with time according to series of reactions Me + Men = Men + 1 and reaction rates are depended on the internal energies of Men clusters. The dependences were obtained from statistical data of molecular dynamics simulations. The results of molecular dynamics method and developed numerical model show a good agreement.

KEYWORDS:

multiscale simulation, condensation, metal clusters

DOI: 10.1134/S0235010619010080

The effect of calcium-containing additives on the extraction of alumina from red muds of alumina production

S. A. Bibanayeva, V. N. Koryukov, V. M. Skachkov, N. A. Sabirzyanov,

V. M. Ufimtsev, E.M. Lebedeva

ABSTRACT

The results of an experimental study of the effect of calcium-containing reagents on the process of high-temperature autoclave extraction of alumina from red muds obtained from Timan deposit bauxites by the parallel BayerEsintering method are presented. The phase composition of products is determined by XRD and EDXR methods. Increased extraction of alumina from red mud when used the surfaceEcarbonized lime in the process is shown.

KEYWORDS

red mud, processing, leaching, calcium oxide

DOI: 10.1134/S0235010618050031

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 slag-forming 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

DOI: 10.1134/S0235010618050055

Model investigation of liquid interaction metal and dispersed steel inclusions in castingon gasificable models

B. S. Vorontsov, N. V. Nesterov

ABSTRACT

A mathematical model for the interaction of liquid metal with metallic inclusions embedded in the foam polystyrene, reflecting the filling of molds, the effect of thermal decomposition of expanded polystyrene and heat exchange of the base alloy and filler material, is developed. The resulted results of the experiment on obtaining prototypes by casting on gasified models, confirming the predictions of mathematical modeling.

KEYWORDS

mathematical model, interaction of metal particles with melt, local alloying, casting for gasified models, composite materials

DOI: 10.1134/S0235010618050158

Thermodynamic analysis of joint aluminothermal recovery ZrO2 and Nb2O5

S. N. Agafonov, A. A. Ponomarenko, A. S. Russkikh

ABSTRACT

In this work, we studied the joint aluminothermic reduction of zirconium and niobium oxides. Thermodynamic modeling of metal-thermal reactions, differential thermal (DTA) and X-ray phase (XRF) analyzes were used in the work. The research can serve as a scientific basis for the development of promising metal-thermal technologies for the production of rare-metal alloys.

KEYWORDS

thermodynamic modeling, aluminothermic reduction, alloy, zirconium, aluminum, niobium, oxides

DOI: 10.7868/S023501061901002X

Studying the processes of producing alloys of the system of Fe–Si–Ni–Cr thermodynamic modeling

V. A. Salina, V. I. Zhuchkov, O. V. Zayakin

ABSTRACT

The results of thermodynamic modeling of the process of restoring the elements of a system containing, masses, are given. %: 40 Cr2O3; 21 FeO; 15 Al2O3; 6 SiO2; 16 MgO; 2 CaO; 0.006 P2O5 with increasing CaO content to basicity 3.15. Ferrosilicone (28% Fe, 65% Si; 7% Ni) is used as a reducing agent. For the simulation, the HSC Chemistry 6.12 software package developed by Outokumpu Research Oy (Finland) was used, the database of which introduced new thermodynamic constants for the CrO compound and corrected for CaCr2O4. It has been established that an increase in the degree of chromium reduction by 32.7% (from 64 to 95.1%) occurs in the interval of increasing the basicity of slag from 0.07 to 1.86. The rational basicity of slag is 1.86–1.9. Increased consumption of reducing agent from 0.5 to 1.05mred allows to increase the degree of chromium recovery by 52.4% and reach a value of 95.1%. The chemical composition of the resulting metal, wt %: 50.4 Cr; 1.97 Si; 3.3 Ni; 0.21 Al; 0.0050 P; Fe—the rest. The simulation results can be used to calculate the process of restoring elements of chrome ore using ferrosiliconikel.

KEYWORDS

thermodynamic modeling, system, silicothermia, basicity, reducing agent consumption, reduction degree, ferrosilicochromic nickel

DOI: 10.7868/S0235010619010183