Northern Caucasian Institute of Mining and Metallurgy (State Technological University), Vladikavkaz, Russia:

V. M. Zarochentsev, Associate Professor at the Department of Information Technologies and Systems,Candidate of Technical Sciences, e-mail: vlazarm@gmail.com
A. L. Rutkovskiy, Professor at the Department of Non-Ferrous Metallurgy and Metallurgical Processes Automation, Doctor of Technical Sciences
I. I. Bolotaeva, Associate Professor at the Department of Information Technologies and Systems, Candidate of Technical Sciences

Vladikavkaz Branch of the Finance University under the Government of the Russian Federation, Vladikavkaz, Russia:
M. A. Kovaleva, Head of the Department “Corporative information and communikation systems”, Candidate of Technical Sciences

For alkali solution electrolysis resulting in the production of lead dioxide on anode and lead sponge on cathode, the concentration of lead on cathode should be high and that on anode should be low. To prevent sponge from coming off of the cathode leading to electrode bridging, low current densities should be used. In this case, the adhesion of sponge to cathode will be stronger. Another solution would be to use a dielectric mesh to separate the cathode and the anode. To improve the process conditions, it is proposed to use a porous lead sponge to separate catholyte from anolyte. The sponge can act as a flow cathode at the same time. A metallic mesh, a row of parallel rods or plates or other type of permeable cathode are proposed as the basis for growing the sponge. The proposed technique helps precipitate the lead sponge predominantly on the backside of the cathode preventing the cathode deposit from hitting the anode and thus preventing electrode bridging. As the cathode sponge goes all the way across the section of the cell, the pregnant solution concentrates in between the cathodes while the weak solution concentrates near the anodes. This leads to a higher depletion of the solution and helps lower the concentration of lead near the anodes and control the generation of lead oxides on anode. Compared with conventional techniques when the sideways growth of the spongy precipitate is constrained by the cross section of the cell (from 200–300 to 400–500 A/m²), this technique also helps significantly increase the current density at low power consumption and obtain a high-purity lead sponge. In comparison with high-intensity electrolysis techniques, the above described technique helps significantly decrease the power consumption, improve the purity of cathode deposits and lower the concentration of lead in the spent electrolyte. This process does not require higher temperatures, thus there is no need in alkaline vapour suppression equipment.

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