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

P. A. Arkhipov, Senior Researcher, e-mail: arh@ihte.uran.ru
Yu. R. Khalimullina, Researcher, e-mail: yu.halim@ihte.uran.ru
A. S. Kholkina, Junior Researcher, e-mail: a.kholkina@mail.ru
N. G. Molchanova, Researcher, e-mail: molchanova@ihte.uran.ru

Two constructions of electrolytic cells for electrolytic refining of lead, obtained from industrial products of non-ferrous metals production, were tested. The first construction is a box-type one with horizontal liquid metal electrodes separated by solid dielectric partitions. The second construction is a type of a “crucible in a crucible” with horizontally aligned liquid metal electrodes separated by a porous wall of the inner crucible. The tests showed that both constructions of electrolytic cells provide the effective separation of lead from metal impurities and allow obtaining grade lead in a single-stage electrolytic refining at the cathode. However, in the box-type cell the refining process is slower than that in the cell with a porous crucible because of the low anode current densities, besides the considerable voltage across the electrodes (7–9 V) of the box-type cell implies high energy costs. The horizontal location of the liquid metal electrodes results in the current load inequality at the metal surface. Therefore, the true values of the current densities do not correspond to the current densities, calculated according to the geometrical dimensions of the anode and cathode. These leads to the disturbances of the electrolytic refining process conditions. A ceramic porous wall of the inner crucible of the second construction of the cell decreases the interelectrode distance several times, reduces the amount of the required electrolyte (KCl – PbCl₂), and drops the voltage across the electrodes up to 1.2–2.0 V, which increases greatly the efficiency of the process of lead electrolytic refining from the metal impurities. The end product, which is grade lead, is formed at the cathode, and alloys with a high content of valuable components (Sb, Bi, Ag) are obtained at the anode. The carried out investigations were carried out partially using the equipment of a multiple-access center “Substance Composition” (Institute of High Temperature Electrochemistry) and a joint laboratory of the Ural Federal University and Institute of High Temperature Electrochemistry “High Temperature tools for distributive electrochemical energetics”.

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