Manufacture of mullite corundum brick

Using synthetic mullite and fused white corundum as raw materials, and using Suzhou soil as a binder, mullite corundum bricks for electric furnace tops can be manufactured.

The synthetic mullite is crushed to <4mm as aggregate, the fused white corundum is ground to <0.074mm as fine powder, and the dried Suzhou soil is vibrated and ground to a fineness <0.5mm as binder. The proportions of ingredients are as follows: synthetic mullite 55~65%, fused white corundum 25~30%, Suzhou soil 8~10%. The ingredients are mixed with a wet mill. When mixing, first add granular material, mix for 1~2min, then add binder and mix for 2~3min, and finally add fine powder and mix for 3~5min, the total mixing time is about 10min. Its particle composition is as follows: >2mm17.9~20.2%, 2~1mm14.3%~18.7%, 1~0.5mm3.9~5.8%, 0.5-0.1mm 13.1~15.9%, <0.1mm41.3~44.7% , moisture 4.6~5.4%.

The green body is formed by a 300t friction brick press, and the green body density is 2.70g/cm3. Embryos are dried in a tunnel dryer. The inlet temperature is 40~50℃, the maximum drying temperature is 130℃, the drying time is 48h, and the moisture content of the embryo body is not more than 1.5%. The product is fired in a tunnel kiln at a firing temperature of 1550°C and a holding time of 10h.

The physical and chemical indicators of the product are as follows: Al2O373.06%, SiO2224.10%, apparent porosity 19.9%, bulk density 2.55g/cm3, normal temperature compressive strength 81.7MPa, 1550℃, 3h reburning line change rate -0.11%, load The softening start temperature was 1710°C.

Mullite corundum bricks are used as upper structure bricks, forehearth bricks, cover plates, metallurgical and other industrial medium temperature furnace linings, carbon black reaction furnace cold section, and other industrial thermal equipment linings.