Impermeable brick for aluminum reduction cell and preparation method thereof

Abstract

The invention discloses an impermeable brick for an aluminum reduction cell and a preparation method thereof. The preparation method comprises the following steps: mixing raw materials of the impermeable brick, carrying out mould pressing, drying and calcining. The raw materials of the impermeable brick contain: by weight, 77-87 parts of pyrophillite, 10-15 parts of high-alumina bauxite, 2-5 parts of clay, 0-1 part of a burn promoter and 1-2 parts of spent pulping liquor, wherein grain size distribution of pyrophillite is 3-1mm32-50wt%, 1-0mm23-35wt% and -0.088mm15-33wt%; average grain diameter of high-alumina bauxite is less than or equal to 10 microns; and average grain diameter of clay is less than or equal to 2 microns. The preparation method is simple. The prepared impermeable brick has high strength, low apparent porosity, excellent cryolite erosion resistance, and can meet the requirement of long life of an aluminum reduction cell.

Description

technical field [0001] The invention relates to the field of refractory materials, in particular to a method for preparing anti-permeation bricks used in aluminum electrolytic cells. Background technique [0002] At present, in the production process of the electrolytic aluminum industry, aluminum electrolytic cells are widely used. Aluminum electrolytic cells are generally composed of a three-layer structure of graphite or silicon carbide working layer, aluminum silicate barrier layer and insulation layer. [0003] In the process of electrolytic aluminum, it is particularly important to maintain the heat balance in the aluminum electrolytic cell. When the temperature is above 700 ° C, Na and NaF can enter the barrier layer from the gaps in the working layer or the pores of the material, and combine with the refractory material of the barrier layer. The formation of minerals such as nepheline and other minerals will cause volume expansion, resulting in the destruction of the...

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Problems solved by technology

[0005] At present, dry anti-seepage materials are generally used in the domestic electrolytic aluminum industry, which can achieve a certain anti-seepage effect, but due to the relatively large impact of on-site construction, the density of construction will directly affect the anti-seepage performance, and the quality is difficult to guarantee. , there are disadvantages such as large construction dust, foreign countries mainly use anti-permeability bricks, and its typical product is Alubar1100

[0006] There are also manufacturers in China who try to produce anti-permeability bricks, mainly using clay as raw material. The porosity of the product is 17-22%, and the compressive strength is 30-50MPa. In the process of use, the material shrinks, which is easy to produce brick cracks. As a result, waste slag and molten aluminum infiltrate from the brick joints, there is a certain gap with foreign products, and the use effect is poor

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