Electrical conductivity and raman spectra of the α-Al2O3 – molten Li2CO3-Na2CO3-K2CO3-NaCl disperse systems

D. Zakiryanova, Е. V. Nikolaeva, А. L. Bove, B. D. Antonov.

ABSTRACT

Information on the specific electric conductivity of the dispersed system a-Al2O3-molten carbonate-chloride mixture of Li2CO3-Na2CO3-K2CO3-NaCl in the temperature range of 455–550 °C is obtained. Using the method of Raman spectroscopy, it was shown that in the investigated temperature range a-Al2O3 does not enter into a chemical interaction with the carbonate-chloride melt. Data on the strength and energy characteristics of the CO32– anion in these systems are obtained.

KEY WORDS

Conductivity, Raman spectra, disperse system, melts.

The high-volage penonena in aluminum Molten chloride electrolytes

L. A. Kazieva, S. I. Suleymanov.

ABSTRACT

The electrical conductivity of the molten chloroaluminates NaAlCl4 and KAlCl4 increases with increasing of electrical field strength and reach the limiting values (the Wien effect) which surpass their usual low-voltage conductivity up to 200 and 700 percent respectively. These results have been obtained on the base of analysis of the microsecond high-voltage discharges in the melts (the Wien effect). After the high-voltage pulses discharges having been completed in the melts, their conductivity and electrolyze current have been found to rise up to 50% and their decomposition potentials has found to decrease more than 20% (the “memory effect”). The relaxation time of a non-equilibrium state reaches 5 minutes and more.
KEY WORDS

activation, melts, chloroaluminates, Wine effect, relaxation, structure, aluminum, conductivity.

Determination of synthesis modes of powder intermetallic compound of composition Co2Er in halogenide melt.

D. A. Kondratyev, I. V. Tolstobrov, A. N. Bushuev, O. V. El’kin, O. S. Bervickaya, O. V. Chernova.

ABSTRACT

The present study examines the synthesis capacity of powdered Co2Er intermetallic compound in molten eutectic Lithium- Potassium Chlorides mix at constant temperature of 850K when using no-current diffusion saturation technique.

Based on the obtained results, the synthesis modes for the specified composition of powdered Co2Er intermetallic compound were derived. The components’ composition ratio of the reaction mix for the metal phase was established, at which point the synthesis of the specified powdered compound could still be possible. In this case, the powdered compound did not contain admixtures of both the other-phase intermetallic compounds and the unreacted metal substrate powder (Co).
The credibility of the obtained findings was confirmed through X-ray fluorescence and X-ray diffraction analyses using the EDX‑720 energy dispersion X-ray fluorescence spectrometer along with the XDR‑7000S X-ray powder diffractometer.

KEY WORDS

powder alloy, intermetallic compound, cobalt, erbium, permanent magnet, diffusion saturation, non-current transfer, expanded salt mixture, phase, Co2Er.

Physicochemical foundations for the synthesis of zinc oxide in molten chlorides

T. A. Rozdjalovskaja.

ABSTRACT

The results of the investigation of chloride ions oxidation during the oxygen bubbling through zinc and alkali metal (Na, K) chloride melts at 600 °C are presented. The amount of gaseous chlorine produced depends on the molar ratio of chlorides in the mixture. It is shown that the amount of released chlorine is directly proportional to the values of the effective polarizing force of the cations. The kinetic characteristics of chlorine formation were determined and calculated: the reaction order, reaction rate constants, and the activation energy values. Particle size, chemical composition, and surface area for some samples of ZnO were determined.

KEY WORDS

zinc and alkali metals chloride melts, zinc oxide production, molten chlorides oxidation.

Extraction of scandium and zirconia from their oxides electrolysis of oxide fluoride melt

V. Suzdaltsev, A. A. Filatov, A. Yu. Nikolaev, A. A. Pankratov, N. G. Molchanova, Yu. P. Zaykov.

ABSTRACT. The main regularities of extraction of scandium and zirconium from their oxides into aluminum during aluminothermic and electrolytic preparation of Al-Sc and Al-Zr alloys and ligatures in KF-AlF3, NaF-AlF3 and KF-NaF-AlF3 oxide-fluoride melts with Sc2O3 additives and ZrO2. The effect of the melt composition and its temperature, the duration of synthesis, the content of Sc2O3 and ZrO2 oxides in melts, the mechanical mixing of aluminum and the cathode current density on the content of scandium and zirconium in aluminum, and their extraction from oxides are determined. It is shown that, depending on the synthesis parameters, the average values of extraction of scandium and zirconium are 20–75 and 40–100%, respectively. The electrolytic decomposition of oxides in melts KF-AlF3, NaF-AlF3 and KF-NaF-AlF3 leads to a significant increase in extraction of scandium and zirconium into aluminum. Based on the results of the research, the parameters for obtaining alloys and ligatures Al-Sc and Al-Zr with scandium content up to 10 and zirconium up to 15 wt.% in the electrolysis of oxide-fluoride melts.

KEY WORDS: scandium, zirconium, oxide-fluoride melt, aluminothermy, electrolysis, extraction.

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.

Conductivity of melts in mixtures of gadolinium trichloride with sodium and potassium chlorides

K. I. Trifonov, I. F. Zabotin, S. F. Katyshev, A. F. Nikiforov

ABSTRACT:

The values of specific conductivity of melted mixtures of gadolinium trichloride with sodium and potassium chlorides have been determined. The values of molar conductivity for the examined salt mixtures have been calculated, and the isothermal projection of molar conductivity for the triple system GdCl3–NaCl–KCl is presented. Analysis of the results received makes it possible to offer a hypothesis on the nature of the components interaction.

KEY WORDS:

specific and molar conductivity, gadolinium chlorides, sodium and potassium, interaction of components.

Potential activity coefficient, dissolved in moltables of its halogenides

V. M. Ivenko, V. V. Chebykin, L. A. Tsiovkina

ABSTRACT:

The parameters of the equations for the activity coefficient of potassium dissolved in KF–KCl, KF–KBr, KF–KI and KCl–KI melts with molar ratio of salt components of 3 : 1, 1 : 1, 1 : 3, as well as in equimolar melts KCl–KBr and KBr–KI. The concentration of potassium in the melts varied, from about 1 to 10 mol %. A representation of the authors on the complex structure of solutions of an alkali metal in mixtures of its halides is given, which makes it possible to understand the dependence of the thermodynamic properties of potassium dissolved in them.

KEY WORDS:

solutions, melts, alkali metals, halides of alkali metals, activity, activity coefficient.

Density and molar volumes of the ternary alloys of two cross sections of Na–K–Cs systems at technically important temperatures

T. M. Taova, V. N. Lesev, F. M. Mal’surgenova

ABSTRACT:

The densities and molar volumes of ternary alloys located on two secant lines going towards Cs and K vertices in Na–K–Cs concentration triangle and including the 13.9Na + 43.5K + 42.6Cs (in at %) eutectic alloy with the melting point of 195.2 K have been presented. The isotherms of density of the ternary alloys for the both sections show a positive deviation from additive law, while the isotherms of the molar volumes correspond to the last law.

KEY WORDS:

density, molar volume, ternary alloy, alkali metal, eutectic alloy, sodium-potassium-cesium

Dynamics of changes in the cluster structure of melts in the process of equilibrium and nonequilibrium crystalization

V. D. Aleksandrov, S. A. Frolova, E. A. Pokintelitsa, A. P. Zozulya, Sh. K. Amerkhanova

ABSTRACT:

A scheme for the cluster structure of a binary melt of the eutectic type in superheated and supercooled states with respect to the liquidus temperatures is developed. The dynamics of the change in the structure of a clustered liquid with cooling and further equilibrium and nonequilibrium crystallization is analyzed. The regions of coexistence of a liquid solution with clusters, nucleus, and a solid phase are indicated. The boundaries of cluster demixing and the ways of their transformation into eutectic colonies are determined by the binodal. Thermograms of cooling characterizing various types of alloys crystallization are considered. On their basis, an analysis of the ways of crystallization from the state diagram is given.

KEY WORDS:

melts, binary system, alloys, state diagram, eutectic, clusterization, nucleus, equilibrium and nonequilibrium crystallization, thermograms, binodal, demixing