Electrofused mullite is made of high purity quartz sand and industrial alumina, melted on an oversized electric arc furnace. Mullite has white color, very low carbon residue, low porosity, low impurity content, high flexural strength, high load softening temperature, high hardness, low creep at high temperature, and well developed needle-like crystals. Compared with sintered mullite, the high temperature mechanical properties and erosion resistance of high purity electrofused mullite are better. High purity electrofusion mullite is light gray, ordinary electrofusion mullite is dark or black, which is due to the presence of silicon and a small amount of iron in the molten block, a small amount of SiO2 because of the rapid cooling of the molten block, the surface is rapidly solidified and closed with the molten block, so that the mullite molten block coloring.