RUSAL Engineering and Technical Center, Bratsk, Russia:

S. I. Nozhko, Head of an Electrolysis Department, e-mail: semen.nozhko@rusal.com

RUSAL, Moscow, Russia:
V. G. Goloshchapov, Manager of Executive Derectorate

“RUSAL Bratsk” JSC, Bratsk, Russia:
S. N. Tikhomirov, Senior Master of Building No. 11 Series
V. V. Volyanskiy, Executive Officer on Electrolysis
S. I. Pentyukhin, Deputy Engineer-Technologist, Electrolysis Directorate

The electrolytic production of JSC “RUSAL Bratsk” has received secondary cryolite with two types, which considerably differ in their chemical composition. The presence of secondary cryolite with different range of chemical composition caused a need to revise the usage ratios for this type of raw material in the electrolytic production. To determine the amount of liquid electrolyte in the electrolyzers for aluminum production, it was decided to develop a metal indication methodology. For the metal-indicator was used a metal, which is more electronegative than aluminum — barium. To the electrolyzers was injected barium chloride (BaCl₂·2H₂O). For the experiment three groups of electrolyzers were identified: electrolyzers for flotation recycling of cryolite (2 pcs.), electrolyzers for recycling of the regenerated cryolite (2 pcs.), electrolyzers witness (2 pcs.). Melting of secondary cryolite for electrolyzers witness was not done. Before the introduction of barium into the electrolyte, linkage was preheated on the crust of electrolyzer cell. The addition of fusing electrolyte was carried out on the first electrolyzer in each group of pots, on the second the electrolyzer fusing with the voltage-additive wasn’t done. Analysis of the results showed that the fusing of the electrolyte from a variety of secondary cryolite is comparable, with the presence of voltage-additive from the secondary cryolite fusing electrolyte does not change. In the future, when determining the weight of the electrolyte in industrial electrolyzers to minimize the risks of occupational health and safety, it is recommended the use of less hygroscopic barium sulfate as an indicator.

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