Impurities have a certain impact on the performance of refractory material, so in the production process, we should try to ensure the purity of raw materials, especially for mullite insulation brick. Impurities can affect chemical properties, which can affect the use life of the furnace.
Firstly, FeO can penetrate the solid solution of mullite, even if it does not have a large effect on the melting point of the mullite, it can darken the glass phase and affect the performance of the mullite insulating brick.
Secondly, excessive alkali metal oxides can reduce the content of mullite, and even destroy the crystallization of aluminum andalusite, while it will have an impact on the glass phase, and affect the properties of mullite insulation brick.
Finally, CaO will slow down the crystallization process of mullite, although little effect, still need to be concerned about. There is a small amount of magnesium oxide producing crystal impurities, so that the mullite phase reduced. mullite light insulation brick is to select strictly raw materials, use high purity mullite, control impurities content.