Peculiarities of cathodic reduction of rhenium (VII) in alkaline electrolytes

Svetlana V. Kovaleva, Irina A. Shabanova, Andrey V. Korshunov

Research output: Contribution to journalArticle

Abstract

Relevance. Rhenium and its alloys are refractory, heat8resistant, high8temperature, and corrosion8resistant materials which are used in aircraft and rocket engineering, electrical engineering, in production of catalysts. Rhenium belongs to rare elements, this necessitates the improvement of technological processes for its extraction from natural raw materials and waste materials, as well as improving the ac8 curacy of analytical methods for its determination. Electrochemical methods are optimal in terms of cost, expressiveness and availabili8 ty for analysis and processing of rhenium8containing raw materials. In this regard, the study of the regularities of the electrode proces8 ses involving rhenium and its compounds is relevant. The aim of the research is to establish the sequence of cathodic reduction of perrhenate ions in alkaline electrolytes. Objects: Ammonium perrhenate solutions, sodium hydroxide solutions. Methods: direct and alternating current polarography, cyclic voltammetry, accumulative potentiostatic electrolysis. Results. The authors have determined the interval of potentials of cathodic reduction of ReO 4 - ions (110- 5- 110 -2 M) in alkaline medium (1..10 M NaOH) at mercury electrodes is -1,25 -1,75 V (sat. Ag/AgCl/KCl). A significant contribution of catalytic and adsorption cur8 rent components to the total value of cathodic current was established on the basis of temperature dependence of limiting current and current dependence on height of dropping Hg8electrode column. A sequence for reduction of ReO4 - in alkaline electrolytes was esta8 blished using cyclic voltammetry, and a scheme of the cathodic process was proposed which includes electrode, chemical and adsorption stages. Experimental data on potentiostatic electrolysis and on voltammetry of chemically synthesized ReO2 were used to interpret the polarographic results. The paper demonstrates the importance of the obtained results for analytical determination of rhenium.

Original languageEnglish
Pages (from-to)163-174
Number of pages12
JournalBulletin of the Tomsk Polytechnic University, Geo Assets Engineering
Volume330
Issue number3
DOIs
Publication statusPublished - 1 Jan 2019

Keywords

  • Alkaline electrolytes
  • Cathodic process
  • Cyclic voltammetry
  • Mercury electrode
  • Perrhenate ions
  • Polarography

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Fuel Technology
  • Geotechnical Engineering and Engineering Geology
  • Waste Management and Disposal
  • Economic Geology
  • Management, Monitoring, Policy and Law

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