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ALUMINIUM, ALUMINA, CARBONACEOUS MATERIALS
ArticleName Current efficiency during the electrorefining of copper-calcium alloy in molten CaCl2
ArticleAuthor Zaykov Yu. P., Batukhtin V. P., Suzdaltsev A. V.
ArticleAuthorData

Institute of High-temperature Electrochemistry of Ural Branch of Russian Academy of Sciences, Ekaterinburg, Russia:

Yu. P. Zaykov, Director, e-mail: dir@ihte.uran.ru

V. P. Batukhtin, Senior Researcher

A. V. Suzdaltsev, Researcher

Abstract

Nowadays, pure Ca is produced from the Cu – Ca alloy, which is electrolytically obtained in CaCl2 – KCl melt or by metallothermal way with following vacuum distillation. Both methods require high energy consumption due to multistage. Therefore, improvement of existing technologies and development of new methods of pure Ca production are urgent. This work is devoted to definition of optimal electrorefining parameters of Cu – Ca alloy in molten CaCl2. It is also aimed at the development of new process of pure Ca production in a single electrolyzer without the use of additional stage of vacuum distillation. The influence of conditions of electrolysis (copper content in Cu – Ca alloy anode, anode and cathode current density, temperature) on the values of cathode and anode current efficiency and cathode Ca purity was investigated in laboratory electrolyzer at the amperage of 20–80 A. It is shown that anode current efficiency is decreased during the decreasing of Ca content in Cu – Ca anode alloy. At the same time, cathode current efficiency is decreased during the increasing of the process temperature and anode current density. Maximum values of cathode current efficiency were obtained at the cathode current density of 4–8 A/cm2 at 58–6 9% (wt.) of Ca in anode alloy. Primary and side reactions are described during the electrorefining of Cu – Ca alloy in molten CaCl2. There is shown an influence of Ca – CaCl2 solutions on the presence of side electrode or chemical reactions. The optimal parameters of Cu – Ca alloy electrorefining were obtained. Obtained and analyzed results can be used for development of new ecologically pure technologies of obtaining of metals (particularly, Ca) and alloys during the electrolysis of CaCl2-based melts.

This work was carried out with the support of the Ministry of Education and Science of Russian Federation, agreement 2012-1.5-14-000-2025-007.

keywords CaCl2, molten CaCl2, solutions, Ca, Cu – Ca alloy, electrorefining, current efficiency, electrolyzer
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