Preparation method of graphene composite protective layer for prebaked carbon anode

Abstract

The invention belongs to the field of carbon anode new materials for the electrolytic aluminium industry, and particularly relates to a preparation method of a graphene composite protective layer fora pre-baked carbon anode. The preparation method includes the steps of (1), adding graphene oxide in distilled water, stirring uniformly ultrasonically, adding phenolic resin with heating and stirring, performing redox reaction to obtain aqueous dispersion solution of graphene phenolic resin; (2) weighing a certain quantity of aqueous dispersion solution of graphene phenolic resin, sequentially adding graphite powder emulsion and nanometer aluminium oxide into the aqueous dispersion solution of graphene phenolic resin, and performing ultrasonic dispersion to obtain a graphene composite coating; (3), taking the graphene composite coating obtained the step (2), adding distilled water to dilute the graphene composite coating, covering the surface of the pre-baked carbon anode with the dilutedgraphene composite coating, and then drying naturally to obtain the graphene composite protective layer. The protective layer can effectively isolate oxidation action of air and carbon dioxide to carbon blocks; the carbon yield ratio in the air reactivity test is greater than 95%, and particularly the carbon yield ratio is greater than 96% after the CO2 reactivity test.

Description

technical field [0001] The invention belongs to the field of new carbon anode materials in the electrolytic aluminum industry, and in particular relates to a preparation method of a graphene composite protective layer for prebaked carbon anodes. Background technique [0002] The anode is the heart of aluminum electrolysis production. In the process of continuous large-scale and intelligent development of aluminum electrolytic cells, the requirements for anode quality are getting higher and higher. High-quality anode carbon blocks have higher strength, lower resistivity, lower CO 2 And air response coefficient, lower ash content. The quality of anode carbon block is directly affected by the quality of baking. [0003] Prebaked anode carbon block with air or CO 2 The carbon loss caused by the reaction has always been a major problem in the electrolytic aluminum industry. With the increasing development of energy saving and consumption reduction, it has become an industry tr...

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Problems solved by technology

However, both methods have relatively large defects. When using the alumina-based anti-oxidation protective layer method, the alumina protective layer participates in the electrode reaction, consumes part of the carbon block, and reduces the service life of the carbon block. In addition, the aluminum-based protective layer and carbon The outer layer of the matrix belongs to two materials with different properties, and the thermal expansion effect is quite different. At the same time, the adhesion between the aluminum-based protective layer and the surface of the carbon substrate is low, which makes the protective layer easy to fall off from the surface of the carbon block.

Unlike the aluminum-based protective layer, the auxiliary method does not have the problem of interface shedding, but the additive method has a large amount of addition, and introduces impurity metals, and the effect of improving the gas reactivity of the carbon block is limited.

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