Corundum mullite brick refers to high alumina refractory products composed of corundum and mullite main crystal phase. Using plate corundum and high-purity fused corundum as the main raw materials, applying advanced ultra-fine powder addition technology, after mixing, forming, drying, high-temperature firing in the shuttle kiln. Corundum mullite brick refers to refractory products made of high-purity or relatively pure raw materials. The presence of low melting point oxide impurities will reduce its high temperature performance.

Use pure mullite raw materials synthesized with industrial alumina powder and pure clay, bauxite or silica as raw materials, especially the alkali metal oxide content should be as low as possible. Products made with mullite granules as aggregates have good thermal shock resistance, but are slightly less resistant to corrosion. Products made of corundum sand as aggregates have good corrosion resistance, but slightly poorer thermal shock resistance.

Performance

It has good high temperature strength, high temperature creep resistance, thermal shock resistance and erosion resistance. The physical and chemical properties of a typical corundum-mullite brick are: Al2O3>85%, Fe2O3 0.45%, apparent porosity 19%, normal temperature compressive strength is greater than 55MPa load softening temperature is greater than 1700 ℃, heating line changes (1600 ℃, 3h)-0.1%, thermal shock resistance (1100℃ water cooling) is greater than 30 times.

Manufacturing process

Synthetic mullite is usually used to manufacture corundum-mullite bricks, which can use mullite particles as aggregate, α-Al2O3 powder as powder, or fused or sintered corundum particles as aggregate and synthetic mullite powder. For powder. Aggregate and powder are compounded according to a certain proportion and particle size gradation. Sulfurous acid pulp waste liquid is used as a binder, and the materials are added in a certain order, fully mixed evenly, and shaped by a friction brick press or hydraulic brick press. After the bricks are dried, they are fired at 1650-1750°C.

Some use fused or sintered corundum sand as aggregate, with mullite or corundum-mullite composition ratio. Using α-Al2O3 high bauxite or clay mixed fine powder as powder to make bricks

Features

It has the characteristics of high refractoriness, good thermal shock stability, high temperature strength, excellent corrosion resistance, strong slag resistance, small expansion coefficient, low creep, anti-stripping, etc., suitable for various atmospheric conditions Use of high-temperature kilns under.

Application

Corundum mullite bricks are widely used in high-temperature sintering of zirconia ceramics, fluorescent materials, electronic ceramics, magnetic materials, ceramic powders, gasification furnaces in the petrochemical industry, two-stage converters for synthetic ammonia, carbon black reaction furnaces, and high-temperature furnaces in the glass industry Other equipment. The appearance size, physical and chemical indexes and service life of the products have reached or exceeded the level of similar products at home and abroad.

Physical And Chemical Indicators