Classification of refractory bricks

1. High-alumina brick: High-alumina brick refers to Al2O3 content greater than 75, fire resistance is higher than clay brick, good resistance to acid and alkali erosion, suitable for cement kiln firing belt, etc., long service life but high price, mainly used It is used for lining blast furnace, hot blast furnace, electric furnace top, blast furnace, reverberatory furnace and rotary kiln. In addition, high-alumina bricks are also widely used as open-hearth regenerative lattice bricks, plugs for pouring systems, nozzle bricks, etc. However, the price of high alumina bricks is higher than that of clay bricks, so it is not necessary to use high alumina bricks where clay bricks can meet the requirements.

2. Dolomite brick: The kiln skin has good performance and good erosion resistance, but there are some f-CaO in the brick, which is easy to be hydrated, difficult to transport and store, and is rarely used in production. Dolomite bricks are widely used in alkaline converters. China's converter lining mainly uses tar-combined dolomite bricks and tar-combined magnesia dolomite bricks. Some factories use lightly burnt oil-fired and fired oil-immersed magnesia dolomite bricks in vulnerable parts.

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3. Magnesia-chrome bricks: good kiln skins, mostly used in firing belts, the disadvantage is poor thermal shock resistance, plus the positive hexavalent Cr is highly toxic, the number of countries producing and using magnesia-chrome bricks in the world is gradually decreasing. Brick production units find alternatives as early as possible.

4. Spinel brick: mostly used for excessive belting, good seismic performance and good reduction resistance, but the fire resistance is slightly worse. The SiO2 content in spinel bricks is low, so there are few silicate minerals with low melting points, all of which are composed of minerals with high melting points, such as square magnesium aluminum (melting point 2850°C) and magnesium aluminum spinel (melting point 2135°C), so It has high temperature resistance.

5. Anti-stripping brick: This brick contains a small amount of ZrO, which undergoes a Martensitic transformation to form fine cracks during the heating process. It has strong alkali resistance, good resistance to spalling and slag resistance.

6. Phosphate bricks: low refractoriness, but high strength and good thermal shock, mostly used in cast chillers and kiln head covers.