Wettable cathode material for aluminum electrolytic cell as well as preparation method and application thereof

Abstract

The invention relates to a wettable cathode material for an aluminum electrolytic cell as well as a preparation method and application thereof. On the basis of high wettability of graphene on aluminumliquid as well as excellent mechanical property and corrosion resistance of the graphene, the conductive surfaces of a carbon block and a metal block are spin-coated with a graphene coating or a composite layer thereof with a certain thickness by a spin-coating coating technology, and the prepared novel cathode has excellent wettability on the metal aluminum liquid, so that the thickness of the aluminum liquid at the bottom of the electrolytic cell is greatly reduced, the polar distance of the electrolytic cell can be reduced to reduce the cell pressure drop, and energy saving and consumptionreducing are realized. Meanwhile, due to the layer structure of the graphene as well as high tensile strength and compressive strength, the electrolyte corrosion resistance of the cathode and the structural strength of the cathode are greatly improved, the original cathode can be plated, and the cathode structure of the electrolytic cell does not need great modification. A metal electrode can befurther prepared, and the pressure drop of the electrolytic cell can be further reduced.

Description

technical field [0001] The invention relates to a wettable cathode material for an aluminum electrolytic cell, a preparation method and application thereof, and belongs to the field of metallurgical equipment. Background technique [0002] The current aluminum electrolytic cell has always used carbon material as the cathode material. Due to the extremely poor wettability between the metal aluminum liquid and the surface of the carbon cathode material, a certain thickness of aluminum liquid must be kept in the current electrolytic cell to avoid exposure of the carbon cathode surface to the electrolyte. The resulting electrode reaction is unstable. The thickness of the aluminum liquid in the current aluminum electrolytic cell is usually about 18-30cm. Such a thick aluminum liquid will fluctuate under the action of electromagnetic force, which will deform the interface between the aluminum liquid and the electrolyte, make the current distribution uneven, and reduce the current ...

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Problems solved by technology

[0003] At present, research on the wettability of cathodes for aluminum electrolytic cells and the corrosion resistance of molten salts is mainly focused on two aspects. One is to change the shape or structure of the cathode. For example, patent CN201320784484.4 discloses a conductive Drill holes on the surface, and fill the holes with TiB that has good wettability with aluminum liquid 2 -C composite material, this structure can greatly improve the wettability of the cathode to the aluminum liquid, but drilling the conductive surface of the carbon block will reduce the mechanical strength of the carbon block, and the composite material is easily eroded by the high temperature lava. The contact surface of the carbon block leads to a decrease in the corrosion resistance of the cathode; the second is to coat the cathode with a material that exhibits good wettability to the aluminum liquid or exhibits corrosion resistance to molten salts to make a composite electrode. The commonly used electrode coating is TiB 2 Coatings, such as patent CN201110274580.X and patent CN03118274.7 respectively disclose a TiB 2 -C composite coating and a TiB 2 / Al 2 o 3 The application of composite material coating on the cathode surface of aluminum electrolytic cell, this type of coating can greatly improve the wettability of the cathode to the aluminum liquid, but the bonding strength between the composite material coating and the carbon substrate is low and easy to fall off, and the coating There is a problem of uneven thickness of the coating. If the coating is too thin, the life of the cathode will be shortened. If the coating is too thick, it will easily lead to cracking during the sintering process, resulting in a reduction in the thermal shock and corrosion resistance of the cathode.

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