Composite and high-conductivity cathode steel bar

Abstract

The invention relates to a cathode steel bar, in particular to a composite and high-conductivity cathode steel bar for a cathode during aluminum electrolysis. The composite and high-conductivity cathode steel bar comprises a conductive base body, wherein a cavity with an opening is formed in the conductive base body, a high-conductivity body is arranged in the cavity, and a sealing body is arranged at the opening of the cavity; and in the cavity, a non-conductive region is arranged among the high-conductivity body, the conductive base body and the sealing body, and the contact parts among thehigh-conductivity body, the conductive base body and the sealing body are conductive regions. The composite and high-conductivity cathode steel bar has the advantages that horizontal current in moltenaluminum is homogenized, the stability of the production of an aluminum electrolysis cell is improved, so that the electrolytic cell can operate efficiently and stably at a low polar distance. The conductive performance of the steel bar is improved, the cathode drop of the electrolytic cell is greatly reduced, and the aluminum electrolysis energy consumption is reduced. The current density on thesurface of a cathode carbon block is more uniform, the abrasion rate of the cathode is reduced, and the service life of the cathode is prolonged. The cathode group is more compact, and the investments relevant to linings, groove shells and workshops are reduced.

Description

technical field [0001] The invention relates to a cathode steel rod, in particular to a composite and highly conductive cathode steel rod for aluminum electrolysis cathodes. Background technique [0002] Metal aluminum is mainly obtained by the Hall-Héroult molten salt electrolysis method in large-scale industrial production, that is, electrolysis of alumina dissolved in an electrolyte with molten cryolite as the main component to produce liquid metal aluminum. [0003] The direct equipment for producing metal aluminum is aluminum electrolytic cell. The aluminum electrolytic cell is mainly composed of two parts, one part is the anode, which is usually made of carbon materials; the other part is the cathode, which is made up of cathode carbon blocks, cathode steel rods and lining materials. [0004] The aluminum electrolytic cell is connected in series in the whole electrolytic series. The current enters the electrolytic cell from the anode, passes through the molten electro...

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Problems solved by technology

[0006] First: The resistivity of the steel rod at high temperature is high, and the physical pressure drop is large. This part of energy does not directly participate in electrolytic production, but is lost in the form of heat, resulting in a large amount of energy waste.

[0007] Second: Since the steel rod and the cathode carbon block are placed horizontally in the same direction, and the current in the aluminum liquid is concentrated at the outlet end of the cathode steel rod, the current density in the horizontal direction in the aluminum liquid is very large. This level of current is the same as that of the aluminum liquid The vertical magnetic field in the medium works together to generate electromagnetic force, which drives the liquid aluminum to flow and fluctuate in the electrolytic cell. If the horizontal current in the electrolytic cell is too large and unevenly distributed, the interface between the molten aluminum and the electrolyte will fluctuate too much. Make the electrolytic cell produce serious instability in production and reduce the current efficiency

In addition, the horizontal current distribution in the aluminum liquid is unevenly distributed along the length of the cathode carbon block, making the current density at the end of the cathode carbon block the largest, thereby significantly accelerating the corrosion of the cathode carbon block here and reducing the life of the electrolytic cell

[0008] To obtain a good energy consumption index by improving the stability of the electrolytic cell, the usual practice is to strictly control the vertical magnetic field distribution in the molten aluminum in the design of the electrolytic cell, which not only increases the difficulty of the cathode busbar design, but also leads to complex cathode configuration , the amount of busbar is large, and the investment increases

[0009] The horizontal current in part of the molten aluminum can be suppressed by improving the cathode structure, but it will increase the pressure drop of the cathode carbon block group, resulting in an increase in energy consumption

[0010] By changing the material of the cathode carbon block, the pressure drop of the cathode group can also be reduced, but the cost of the cathode carbon block group is almost doubled, and the horizontal current in the aluminum liquid increases, which is not conducive to the stable production of the electrolytic cell

[0011] It can be seen that none of the above methods can reduce the horizontal current in the aluminum liquid in the aluminum electrolytic cell and reduce the physical pressure drop of the aluminum electrolytic cell

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