High conductivity low-temperature electrolytes for aluminum electrolysis and use method thereof

Abstract

The present invention provides low-temperature electrolyte for high conductivity aluminum electrolysis and an application method thereof. The invention is characterized in that the low-temperature electrolyte for high conductivity aluminum electrolysis comprises the following compositions in weight percentage: 38 to 51 weight percent of NaF, 30 to 47 weight percent of AlF3, 2 to 3 weight percent of Al2O3, 2 to 5 weight percent of CaF2, 1 to 8 weight percent of NaCl, 0 to 8 weight percent of LiF, 0 to 5 weight percent of MgF2, 0 to 3 weight percent of LiCl, and 0 to 3 weight percent of MgCl2. The application method comprises the following steps: electrolysis application is carried out at a temperature of between 805 and 915 DEG C, with current density of anode of between 0.83 and 1.0 ampere / centimeter<2>, and the primary crystal temperature of the electrolyte is between 800 and 900 DEG C. The electrolyte can improve the physico-chemical performance of cryolite-alumina solution, reduce resistance consumption, improve electric power, save electric energy and reduce the cost. With the electrolyte, the electrolysis temperature can be greatly reduced, and the conductivity of the electrolysis is between 2.25 and 2.60 Siemens / centimeter.

Description

technical field [0001] The invention belongs to the field of molten salt electrolysis of non-ferrous metal metallurgy, and in particular relates to a low-temperature electrolyte for aluminum electrolysis with high conductivity and a use method thereof. Background technique [0002] At present, the aluminum electrolysis industry has been using the traditional Hall-Heroult method, and its electrolyte is Na 3 AlF 6 -Al 2 o 3 , often adding CaF 2 Or CaF is generated due to the addition of calcium oxide by raw materials 2 . In order to control the molecular ratio (Na 3 AlF 6 NaF and AlF in 3 The ratio of the amount of substance), usually with the addition of AlF 3 , the molecular ratio of the electrolyte is controlled within a certain range, the purpose is to improve the properties of the electrolyte, mainly to reduce the primary crystal temperature and achieve lower temperature electrolysis to achieve the purpose of energy saving. The future development trend is still t...

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Problems solved by technology

[0003] But with too much AlF 3 If the molecular ratio is reduced, the conductivity of the electrolyte will decrease, and the resistance will increase, thereby increasing the power consumption. During the electrolysis process, a considerable amount of power is consumed in the resistance loss of the electrolyte itself, which directly affects the electric energy produced by aluminum electrolysis. Consumption, the voltage drop of the electrolyte accounts for about one-third of the voltage drop of the entire electrolyzer

[0004] Since the birth of the Hall-Heroult method, aluminum electrolysis scientists have conducted a lot of research, during which they experimented with various chlorides, sulfides, carbonates, sulfates, and aluminates to replace cryolite, but it is difficult to succeed in industry. application

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