The main components of sintered mullite include the following oxides, and the specific content will be different according to the product grade and production process:

I. Alumina (Al₂O₃)

Content range: usually between 38% and 80%.

Function: Alumina is one of the core components of sintered mullite. The higher its content, the more complete the formation of mullite phase, and the higher the refractoriness and hardness of the material.

II. Silicon dioxide (SiO₂)

Content range: usually between 20% and 45%.

Function: Silica and alumina together form the chemical basis of mullite, and proper amount of SiO₂ contributes to the formation and stability of mullite phase.

III. Iron oxide (Fe₂O₃)

Content range: usually ≤1.2%.

Function: Iron oxide is an impurity component, too high content will reduce the refractoriness and corrosion resistance of mullite.

IV. Titanium oxide (TiO₂)

Content range: usually ≤0.5%.

Function: Titanium oxide is also one of the impurity components, and its high content will affect the properties of mullite, especially in high temperature environment.

V. Potassium oxide (KO) and sodium oxide (Na₂O)

Content range: The total content of KO and Na₂O is usually ≤0.4%.

Function: These alkali metal oxides are impurity components, which will inhibit the formation of mullite phase and increase the content of glass phase, thus reducing the refractoriness and mechanical strength of the material.

VI. Magnesium oxide (MgO) and calcium oxide (CaO)

Content range: the total content of MgO and CaO is usually ≤0.5%.

Function: These oxides are also impurity components, and too high a content will reduce the performance of mullite.

VII. Other ingredients

Sintered mullite may also contain a small amount of other oxides, such as P₂O₅ and MnO, but its content is usually low.

The content of these components directly affects the properties of sintered mullite, such as refractoriness, corrosion resistance and thermal shock stability.