TRANSFORMATION OF THE NATURE OF THE CONDUCTIVITY OF HIGHLY CONDUCTIVE CHALCOGENIDE MELTS TO TOWARDS THEIR ELECTROLYTIC CAPACITY

ABSTRACT

Melnik N.I., Mustуatsa O.N. Transformation of the nature of the conductivity of highly conductive chalcogenide melts towards their electrolytic capacity. Visnyk National Transport University. Series «Technical sciences». Scientific and Technical Collection. - Kyiv: National Transport University, 2021. - Issue 1 (48).

Ibe aim of this work is to study the nature of the conductivity of melts of iron chalcogenides (Fe-Se, Fe-Te, FeS-Na2S) and the conditions of its possible transformation in order to bring the high-conductivity melt to a state suitable for electrolytic decomposition into metal and chalcogen. To solve this problem, a set of methods was used - electrical conductivity (ж), thermo-EMF (a), polarization characteristics (І-V) and electrolysis (n). ж of high-conductivity melts was investigated by the four-probe method on a direct current in a quartz U-shaped cell of capillary type with graphite electrodes and molybdenum current leads in the direct current mode. The systematic error due to the accuracy class of the devices is 1%; random - does not exceed 1%. Low ж melts were studied by the two-probe AC method. Due to the high chemical aggressiveness of FeS-Na2S melts, a measuring cell with an alundum capillary was developed. Random error when measuring ж two-probe method on alternating current is 3%, systematic - is within 2%. Thermo-EMF was measured by the differential method with respect to tungsten probes. The temperature difference between the probes was recorded by a differential thermocouple. Systematic error in measuring thermo-EMF was 2%, random - 1.5%. Polarization characteristics were removed by the method of direct current in a simple cell without separation of electrode spaces. In cells of this type in an argon medium over the melt and experiments on electrolysis were performed.

It is established that all samples are characterized by significant values of electrical conductivity (of the order of thousands of Sm/cm) and its negative temperature coefficients; the absolute thermo-EMF of all samples is units of цУ/deg. Melts are qualified as electron-ion (polyfunctional) conductors with a predominant metallic contribution to the conductivity. The introduction of Na2S into the FeS melt leads to a decrease in electrical conductivity and the transformation of its temperature dependence to the inherent ionic compounds. The melt electrolysis of the FeS-Na2S system with the production of iron was carried out. Thus the possibility of transformation of the nature of conductivity of highly conductive chalcogenide melts of iron towards their electrolytic ability is proved. The obtained results must be taken into account when using electrochemical technology of processing polymetallic sulfide ores, which include metal chalcogenides of iron family.

KEYWORDS: MELTS, IRON CHALCOGENIDES, NATURE OF CONDUCTIVITY, ELECTRIC CONDUCTIVITY, TRANSFORMATION, ELECTROLYTIC CAPACITY.

REFERENCES

  1. Da^y E.A. / A.Dancy, G. Derge // Trans. Metall. Soc. AIME. - 1963. - V. 227. - No. 10. - P. 1034.
  2. Argyriades D. Electrical conductivity of molten FeS / D. Argyriades, G. Derge, G.M. Pound // Trans. Metall. Soc. AIME. - 1959 .-- V. 215 .-- P. 909.
  3. Dancy E.A. / A. Dancy, H. Pastorek, G. Derge // Trans. Metall. Soc. AIME. - 1965 .-- V. 223 .-­P. 1645.
  4. Vostryakov A.A. Viscosity and electrical resistance of liquid alloys of iron with phosphorus and sulfur / A.A. Vostryakov, N.A. Vatolin, O.A. Esin // Physics of metals and metal science. - 1964 .-- T.18. - Number 3. - S.476-478. (Rus)
  5. Yablonsky Yu.A. Electrical conductivity of copper, iron and nickel sulfides at high temperatures / Yu.A. Yablonsky, V.I. Smirnov // Izv. Universities. Color metallurgy. - 1958. - No. 2. - P.44-55. (Rus)
  6. Dubrovinsky I.E. Viscosity and electrical conductivity of liquid alloys of iron, nickel and cobalt with sulfur / E. Dubrovinsky, S.K. Chuchmarev // Izv. Universities. Color metallurgy. - 1968. - No. 2. - P.19-23. (Rus)
  7. Barmin L.N., Esin O.A., Dobrovinsky I.Ye. Viscosity of Fe-S, Ni-S, Co-S and its relationship with thermodynamic properties / N. Barmin, O.A. Esin, I.E. Dobrovinsky // In the book: Thermodynamic properties of melts. - Novokuznetsk. - 1969 .-- S. 59-65. (Rus)
  8. Dobrovinsky I.Ye. Electrical resistance of melts containing sulfides of iron, nickel, cobalt and copper / E. Dobrovinsky, O.A. Esin, L.N. Barmin // Izv. Universities. Color metallurgy. - 1970. - No. 2. - P.73-77.(Rus)
  9. Nikiforov L.V. / V. Nikiforov, Yu.A. Liner, D.M. Chizhikov // Sat. Research of processes in metallurgy of non-ferrous and rare metals. - Moscow: Nauka, 1969 .-- P. 80. (Rus)
  10. Mott N.F. On the Transition to Metallic Conduction in Semiconductors / F. Mott // Canad. J. Phys. -1956. - V. 34. - P. 1356.
  11. Mott N. Electrons in disordered structures / Mott. - M .: Mir, 1969 .-- 172 p. (Rus)
  12. Mott N. Electronic processes in non-crystalline substances / Mott, E. Davis. - M .: Mir, 1974 . -- 472 p. (Rus)
  13. Goodenough D. Magnetism and chemical communication / Goodenough. - M .: Metallurgy, 1968 .- 325 p. (Rus)
  14. Moozer E. Recognition and classification of semiconducting compounds with tetrahedral sp3 bonds / E. Moozer, W.V. Pearson // J. Chem. Phys. - 1957. - V. 26. - РР. - 893-899.
  15. Pearson W.B. Optical properties and electronic structure of crossroads material MnTe / W.B. Pearson // Can. J. Phys. - 1957. - V. 35. - P. 886.
  16. Heiderich V.A. Thermodynamic properties of alloys of some transition metals / V.A. Heiderich // Diss. Doctorate in Chemistry - M .: Moscow State University. M.V. Lomonosov. -1974. - 281 p. (Rus)
  17. Gerasimov Ya.I. Chemical thermodynamics in nonferrous metallurgy. Reference Guide. In 8 volumes / Ya.I. Gerasimov et al. // M .: Metallurgizat, 1960. - Vol. 2. - 262 p. (Rus)

AUTHOR

Melnik N.I., Ph.D., associate professor, National Transport University, associate professor department of road construction materials and chemistry, e-mail: kataeff@ukr.net тел. 044-497-33-56, Ukraine, 01010, Kyiv, Omelyanovicha-Pavlenko str., 1.

Mustyatsa Oleg N., Ph.D., associate professor, National Transport University, professor department of road construction materials and chemistry, e-mail: oleg.mustyatsa@gmail.com, td. 044-275-47-60, Ukraine, 01010, Kyiv, Omelyanovicha-Pavlenko str., 1.

REVIEWER

Andriyko О.О., Ph.D., Chemie (Dr.), professor, Kyev National Taras Shevchenko University, professor, department of general and inorganic chemistry, Ukraine, 03056, Kyiv, Av. Peremogy, 37.

Berezina N.O., Ph.D., associate professor, National Transport University, associate professor, department of road construction materials and chemistry, Kyiv, Ukraine.

Article language: Ukrainian

Open Access: http://publications.ntu.edu.ua/visnyk/48/208-216.pdf

Print date: 15.03.2021

Online publication date: 05.04.2021

 

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