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

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.