Aluminium electrolyzer cathode structure capable of reducing voltage and improving current distribution

Abstract

The present invention relates to the technical field of aluminum electrolysis. Provided is an aluminum reduction cell cathode structure that reduces voltage and improves current distribution. The bottom of a cathode carbon block is provided with two steel bar slots or four steel bar slots arranged in two rows of two, each steel bar slot being provided with a cathode steel bar; the gap between the top of each cathode steel bar and the cathode carbon block steel bar slot is filled with carbon powder material, and cold ramming paste or hot ramming paste is used between the two sides of each cathode steel bar and the steel bar slots. The solution provided by the present invention reduces the horizontal current in cathode molten aluminum in reduction cells, reduces the cathode voltage drop, and reduces the temperature of the upper surface of the cathode carbon block, thereby increasing the efficiency of the current in the aluminum reduction cell and reducing energy consumption.

Description

technical field [0001] The invention belongs to the technical field of aluminum electrolysis, and particularly relates to a cathode structure of an aluminum electrolytic cell capable of reducing voltage and improving current distribution. Background technique [0002] Aluminum electrolysis production needs to consume a lot of electric energy. For aluminum electrolysis production, its DC power consumption W (kWh / t-Al) can be expressed as W=2980×V 平 / (CE), where V 平 is the average cell voltage (V) of the electrolytic cell, and CE is the current efficiency (%) of the electrolytic cell. It can be seen from the above formula that the DC power consumption per ton of aluminum produced by aluminum electrolysis is determined by the cell voltage and current efficiency. A reduction in cell voltage of about 0.1 volts can reduce DC power consumption by about 300 kWh / t-Al, and every 1% increase in current efficiency can reduce DC power consumption by about 150 kWh / t-Al. [0003] The cat...

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Problems solved by technology

[0004] 1. The cathode voltage drop of the electrolytic cell is relatively large. When the cathode carbon block with anthracite as the basic material is used, the cathode voltage drop is 300-350mV on average. The reason for such a high cathode voltage drop is: the resistance of the cathode carbon block Large; the conductive distance between the upper surface of the cathode carbon block and the upper surface of the cathode steel rod is long and the resistance is large; if a cathode carbon block with a high degree of graphitization is used, the voltage drop in this conductive distance can be reduced, but the cathode with a high degree of graphitization The price of carbon blocks is high and the investment is large;

[0005] 2. The current density of the cathode steel rod is larger, and the resistance of the cathode steel rod is larger;

[0006] 3. Due to the large cathode voltage drop, the heat generated by the cathode part is large. If the bottom of the electrolytic cell is overheated, it will easily cause the temperature of the bottom of the cell to be too high, which will reduce the current efficiency; Energy consumption, especially for new type cathode structure electrolyzers, when the insulation of the bottom of the tank is too strong, this situation is unavoidable;

[0007] 4. Since the resistivity of the aluminum liquid is much smaller than that of the carbon material of the cathode carbon block, the current combined connection structure of the cathode carbon block and the cathode steel rod of the electrolytic cell is likely to cause the longitudinal direction of the cathode carbon block in the cathode aluminum liquid of the electrolytic cell. The horizontal current is too large; under the action of the vertical magnetic field in the electrolytic cell, this horizontal current has a bad influence on the hydrodynamic state and current efficiency of the aluminum liquid in the electrolytic cell

[0009] It should be said that this cathode steel rod structure is indeed effective in reducing the horizontal current distribution in the electrolytic cell along the longitudinal direction of the cathode carbon block and in improving the stability of the electrolytic cell cathode aluminum liquid and improving the current efficiency of the aluminum electrolytic cell. However, this cathode The steel rod structure also has the following disadvantages: the production of the cathode steel rod and the installation process on the cathode carbon block of the electrolytic cell are relatively complicated; The abrasion resistance of the insulating material used in the lower part of the electrolytic cell is a problem that has not been tested in practice. Once the electrolyte or aluminum liquid penetrates or leaks into these parts, it may have an impact on the destruction of the cathode steel rod and the life of the electrolytic cell.

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