Fused Zirconium Corundum Brick

Zirconia corundum electro-casting refractory

Manufacturing process of zirconium-containing corundum bricks Using zircon concentrate or industrial zirconium oxide, industrial alumina powder as raw materials, sodium oxide, calcium oxide, boron oxide and rare earth metal oxides as additives, the powder is melted at above 2500℃ by arc melting method, and cast in a mold, and then cooled, annealed and machined into fused and rebonded zirconium corundum bricks that meet the requirements.

 

Fused and rebonded zirconium corundum bricks are the most important refractory materials for the normal operation of glass tank furnaces. The high melting rate, long furnace order and low fuel consumption of current glass tank furnaces are mainly achieved by using fused and rebonded zirconium corundum bricks.

1. Raw materials

The raw material of alumina is chemically treated industrial alumina powder. Zirconia is introduced by selected high-purity zircon (ZrO2·Si02). The weight ratio of ZrO2 to Si02 in zircon is approximately 2. When producing No. 30 zircon corundum bricks, the weight ratio of ZrO2 to Si02 in the brick is below 2, and ZrO2 is introduced by zircon. However, when producing No. 35 and No. 40 zircon corundum bricks, since the weight percentage of ZrO2 to Si02Si0 reaches more than 2, in addition to zircon, a part of ZrO2 powder is also used.

ZrO2 powder is made in an electric furnace with zircon as raw material and a reducing agent added. At high temperature, Si02 in molten zircon is reduced to Si or generates SiG and precipitates or volatilizes. Thus, ZrO2 can be obtained.

2. Crystalline phase composition

The composition of zirconium corundum fused brick is in the triangle of ZrO2, Al2O3, 3Al2O3, and 2Si02. Therefore, the final crystallization of the melt should be these three phases, and converge at point. During the cooling process, initially, baddeleyite (ZrO2) and corundum (Al2O3) crystallize in the ZrO2-Al2O3 two-component system. The residual liquid phase moves along the xY line to Y, and mullite (3Al2O3·2Si02) should be precipitated, and mullite crystallization ends at point Y. This crystallization process is carried out in an ideal pure ZrO2, Al2O3, and Si02 system. In fact, due to the introduction of a small amount of Na20 in the brick, it is difficult for mullite to precipitate in this small temperature range in the mullite precipitation area, so it exists in the brick body as a glass phase. Therefore, in zirconium corundum bricks, due to the introduction of a small amount of Na20, generally 0.6-2.0%, there are only three phases of corundum, baddeleyite, and glass phase in the brick.

Due to different cooling conditions, the crystal phase ratio varies in different parts of the fused-reinforced zirconium corundum bricks.

Hot Tags: fused zirconium corundum brick, China fused zirconium corundum brick manufacturers, suppliers, factory, Precision Casting Surface Sand Mullite Sand Powder, Sintered Mullite Bricks, Pellets Sintering Castables Prefabricated Parts Spraying painting Materials, Phosphate Bricks, Cast Alumina Bricks, High Alumina Poly Light Ball Insulation Brick