Why Do We Need to Add Silica Fume to Refractories?

Refractory castables are made of grains of different sizes. Even with careful grading, empty spaces remain between the grains, and those spaces weaken the lining.

Refractory grade silica fume has particles around 0.15 micrometre, so it fills these tiny voids. This improves particle packing, lowers porosity and creates a denser, more cohesive matrix. It also helps low cement castables flow well with less water.

Better packing means higher strength, lower permeability, better durability at high temperature and a longer service life for furnace, kiln and foundry linings.

That is why silica fume is a key ingredient in low cement castables and high-performance monolithic refractories for steel and cement plants.

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