Bi-polar composite electrode for electrolyzing aluminum

Abstract

The present invention provides a bipolar composite electrode for aluminum electrolysis that is composed of cathode material with aluminum wetness and inert anode material. The anode layer and the cathode layer both of 2-200mm thick are joined together by compaction or cementing. The cathode layer is also a porous structure with aperture of 1mm-10mm and the interstitial surface area takes 20-80% of the electrode area. This bipolar composite electrode features that small amount of Aluminium that deposits at cathode is moved to the working face of the anode to form a compact protecting oxide film with equal dissolving rate and forming rate to depress the corrosion of the anode. The electrodes are arranged in series without connecting wires solving the connection problem of inert eletrodes. The electrolysis tank has a simple structure and convenient operation, which will reduce the cost of aluminum production.

Description

technical field [0001] The invention relates to the technical field of aluminum electrolysis, in particular to a bipolar composite electrode for aluminum electrolysis. Background technique [0002] The aluminum electrolysis industry is the basic industry of the national economy and is famous for its energy consumption. Producing 1 ton of aluminum requires 14,000-15,000 degrees of electrical energy, about 2 tons of alumina as raw material, and about 500 kilograms of high-quality carbon materials. At the same time, 1.6-2.0 tons of CO2 gas and other harmful gases are emitted to the environment. my country's aluminum output in 2005 was about 7.8 million tons, accounting for 1 / 4 of the world's total aluminum output of 31.87 million tons. The aluminum electrolysis industry not only consumes a lot of energy, but also consumes a lot of resources every year. Among them, the consumption of carbon anode alone requires more than 3 million tons of high-quality petroleum coke and more t...

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Problems solved by technology

[0007] In 2004, Northeastern University conducted a 3000A inert electrode multi-chamber electrolyzer test in the laboratory, using figure 2 (a) Arrangement mode, the experiment found that the connection between the electrode and the power conductor is easily corroded by the electrolyte, which changes the resistance of the cell, resulting in uneven current distribution in each electrolytic cell, which will affect other connections , which accelerates the corrosion of the joint

[0009] As early as the 1960s, the Italian aluminum company began to develop bipolar inert anodes, and designed an 8-chamber electrolytic cell, the anode used was SnO 2 base anode with TiB 2 The inert anode combined with the cathode, due to some reasons such as the corrosion of the anode, the test did not continue

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