Bauxite mineral composition is mainly for hard diaspore monohydrate (diaspore, kaolinite, illite and montmorillonite, titanium impurity mineral of iron ore, limonite, pyrite, tourmaline, calcite, quartz and so on, its chemical composition is mainly alumina, alumina and water, and contains a small amount of titanium oxide, ferric oxide, calcium oxide and magnesium oxide and potassium oxide, alumina and organic impurities.

Among them, alumina is the main beneficial component of bauxite, the higher the content of alumina, the higher the refractoriness. Silica is mostly aluminosilicate in clay and a little free silica.

Free silica can abate plasticity of the clay and the cohesive force, the iron mineral (iron oxide) is one of the most common harmful impurities in refractory clay, can reduce the slag resistance and refractoriness of products, and make the welding scar refractory products. Content of calcium and magnesium carbonate and sulfate minerals, long can lower clay refractoriness, increase products sintering shrinkage rate, lower refractoriness under load and the products produced cracks, titanium dioxide in refractory clay has different effects, according to the content of the right amount of titanium oxide during sintering can act as fluxing agent, can promote the sintering, but excess of titanium dioxide are lower refractoriness and reticular cracks. High content of potassium oxide and sodium oxide in clay can reduce weight softening temperature of products. Organic matter is one of the common impurities in clay. When the content is too high, it can reduce the slag resistance and increase the loss of burning.