National University of Science and Technology “MISiS”, Moscow, Russia:

A. P. Lysenko, Professor of the Department of Non-ferrous Metals and Gold, Candidate of Technical Sciences, e-mail: reikis@yandex.ru
V. P. Tarasov, Head of the Department of Non-ferrous Metals and Gold, Professor, Doctor of Technical Sciences, e-mail: vptar@misis.ru
I. M. Komelin, Leading Engineer of the Department of Non-ferrous Metals and Gold, e-mail: komelin@mail.ru

The main constructive solutions for electrolysis baths improvements have been considered and priority solutions have been defined. The characteristics of diaphragmless and bipolar electrolyzer have been presented. The advantages of the bipolar electrolyzer using previous improvements of the electrolyzer construction have been demonstrated.
– the bipolar electrodes increasing productivity by 3 times in comparison with monopolar ones at an identical current capacity and also cutting down specific consumption of the electric power from 13.5 to 10 kWh/kg of Mg;
– the tightness of the electrolyzer ,reducing electrolyte and chlorine losses, makes possible to remove the technical sanitary pump, stop the pumping of slime- electrolyte mix and slime extraction and to refrain from replacement of anodes for the entire period of operation as well;
– proceeding the process electrolysis at a low temperature (655 ^оC) for decreasing magnesium losses as a result of a reverse reaction of magnesium with chlorine;
– heating of electrolyte and magnesium with the help of heating alternative current electrodes during the period of its extraction and cooling after the end of the process by using the air-electrolyte heat exchanger;
– maintenance of electrolyte constant level by means of using the ballast capacity filled with argon to simplify the overflow of magnesium into the combined cell and decrease its losses in this way;
– using water cooling for the electrolysis intensification (the rising of load without electrolyte overheating;
– small interpolar distance reduces the voltage on a electrolyzer and the specific expense of the electric power.
Out of all construction improvements listed above, in the E230 SVO electrolyzers being installed at the Russian plants these days, only water cooling of anode heads is used. All listed electrolyzers (including the bipolar one) have one common drawback, it is low current efficiency within the range of 78–85%. The method of electrolysis process which results in accumulating of solid magnesium on the cathode surfaces has been suggested. This method reduces the intensity of reverse interaction between chlorine and magnesium. The technique of magnesium electrolysis laboratory experiments has been given under different temperature conditions and the received results are also presented. It was shown that carrying out the process of solid state magnesium electrolysis increases an output current up to 95–96%. Due to the results of the work done, the main directions of construction and technology improvement in the electrolytic production of magnesium have been formulated.

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