Fused cast alpha-beta alumina cylindrical brick and production method thereof

Abstract

The invention discloses a fused cast alpha-beta alumina cylindrical brick, wherein inner and outer ends at four corners of hollow cylinder wall are all chamfers, middle parts of upper and lower ends of four cylinder walls are provided with position-corresponding protrusions or recesses, the dimension ratio of the height of the protrusions to the depth of the recesses is 1:5, the formula of the brick includes 10-30% of recovered fused cast alpha-beta alumina clinker, and fused cast alpha-beta alumina brick raw material as the balance, which is homogeneous to the recovered clinker. The production method of the fused cast alpha-beta alumina cylindrical brick comprises the steps of: blending materials at first; feeding nitrogen in through the upper part of a hollow electrode, fusing the materials according to a low-voltage large-current fusing process in which the fusing voltage is 180 to 280V, the current is 4 to 9 thousands A and the constant conduction pressure of the nitrogen is 0.3 to 0.8MPa; then implementing casting formation, wherein the cast form adopts body clinker or magnesite integral sand mould, the weight ratio of mould sand to water glass is 90-100 : 6-10, the water glass modulus is 3.2 to 3.3, the casting temperature is 1900 to 2000 DEG C, and the casting speed is 180 to 200kg / min; annealing by using a silicon-aluminum hollow sphere as heat preservation medium after the casting, wherein the annealing speed is 0.053 to 0.060 DEG C / kg . h; and in the end, forming the cylindrical brick by means of cold working.

Description

Technical field: [0001] The invention belongs to the category of refractory materials, and relates to melting and casting α-β alumina cylindrical bricks and a production method, and the products are mainly used for building regenerators of modern glass melting furnaces. Background technique: [0002] At present, the regenerators of glass melting furnaces generally use Siemens-style or basket-style lattices built with sintered magnesia bricks, magnesia-chrome bricks and low-porosity clay bricks. AZS (zirconia corundum) special-shaped brick multi-layer masonry tube-shaped lattice body. The cylindrical bricks are used to replace the original strip bricks. The lattice body is chimney-shaped and is not easy to be blocked. The cylindrical lattice bricks generally retain the physical and chemical properties of the original strip bricks, and are convenient for masonry. The bricks are aligned up and down and there is basically no free hanging part. The structure It is stable and has...

AI Technical Summary

Problems solved by technology

[0004] However, due to the α-Al in the fused-cast α-β alumina products 2 o 3 The thermal expansion coefficient is large, the crystallization temperature range of the material liquid is narrow, the glass phase content of the product itself is small, and the shape of the cylindrical brick is complex, and the casting has a large internal structural stress and geometric temperature difference stress. If you continue to use fused cast α-β alumina ordinary brick If the conventional process is adopted, uniformly dispersed micropores will not be formed inside the product, which can neither adapt to the use conditions of the regenerator temperature cycle change, but also lead to unavoidable quality defects such as product cracking, low yield, and cannot organize industrial-scale production

Therefore, as of now, there is no industrial-scale batch casting of α-β alumina tubular bricks on the market.

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