With the development of the Alumina industry, refractory materials for Aluminum alloy smelting furnace and holding furnace transfer from phosphate-bonded high alumina brick to low cement castable. To avoid molten alumina permeating into refractory materials, anti-wetting agents are often used to increase wetting angles between molten alumina and refractory materials, moreover, extending their service life at high temperature.

As for the heating surface of alumina, alumina alloy smelting furnace and holding furnace, low cement castable have taken the place of phosphate-bonded high alumina brick. The reasons are as follows: in the structure of low cement castable, the pore size is so little that it is difficult for molten alumina and alumina alloy to permeate into refractory materials, which can avoid oxidizing materials in refractory materials being reduced. In addition, low cement castable have perfect abrasive resistance. In recent years, the nature of low cement castable has been improved, due to the use of molten alumina as additive agents increasing wetting angles. Therefore these new materials gradually take the place of traditional phosphate-bonded brick and low cement castable.

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http://www.yilongrefractory.com/news/The%20development%20of%20unshaped%20refractory%20materials%20for%20industrial%20furnace.html