Refractory ramming material is made of reasonably graded granular and powdery refractory materials, mixed with an appropriate amount of binder. It is a dry or semi-dry loose mud-like material. According to the national standard, the deformation index is less than 15%. It needs to be It can be compacted only after strong ramming, so it is called refractory ramming material.
Refractory ramming materials are named after the material of the refractory materials used, such as zirconium ramming materials (acidic), corundum ramming materials (neutral), magnesia ramming materials (alkaline), and are selected according to the use conditions. Since the refractory ramming material is in direct contact with the molten liquid, the refractory material is required to be corrosion-resistant, volume stable (reaching zero expansion) and very dense (related to material gradation). Binders are selected according to material conditions and usage requirements. Various inorganic binders are commonly used, such as aluminum phosphate, sodium phosphate, aluminum sulfate, sodium silicate, magnesium chloride, and sometimes organic binders are also added. In some ramming materials, refractory fibers are also used as reinforcing materials.
The normal temperature strength of refractory ramming material before sintering is low, and it only has high strength after sintering. Therefore, the various high-temperature properties and service life of refractory ramming materials are related to the sintering quality before use. The sintered body should not shrink, expand or crack, and should be firmly combined with the underlying refractory bricks.
In the past, zircon sand ramming material was often used at the bottom of the glass kiln. Its composition (%) is: ZrO2:62, SiO2:32, Al2O3:2, Fe2O3:0.5, the bulk density is greater than 3g/cm3, and the refractoriness is above 1790℃ , the maximum particle size is 0.5mm. The binding agent is aluminum dihydrogen phosphate, which has strong bonding, high strength, and high temperature resistance. However, it is easy to dry and agglomerate. It should not be left for a long time. It is corrosive to the skin and is inconvenient to use. Zirconium corundum ramming materials have been gradually switched to use. AZS brick waste is commonly used as refractory aggregate. The composition (%) of the ramming material is ZrO2:30, SiO2:48, Al2O3:20, the mineral phase is α-Al2O3, mullite, baddeleyite and glass phase, and the maximum particle size is 5mm. When using, you only need to add water and stir. The volume density reaches 3.2g/cm3, the porosity is 12%, the tendency of bubbles is weak, and it has strong resistance to glass liquid erosion at 1400°C. It can also be used as sealing layer and mud material. Recently, low-shrinkage AZSC ramming materials have been developed and applied in China. It introduces a certain amount of chromium-containing materials into the basic components of AZS, with a volume density of ≥2.9g/cm3, a reburning line shrinkage (3h at 1400°C) of less than 0.2%, and an erosion resistance of molten glass and molten metal that is better than the above two. Plant ramming material. When used, just add water and stir, and it can also be used as a sealing layer and castable.
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