The invention discloses a method for preparing a high-purity
mullite material by taking
molten silicon dioxide as a
silicon source. The method is characterized by comprising the following steps: a, mixing, in percentage by
mass, 75-94 wt% of a
silicon dioxide
raw material, 4-20 wt% of an aluminum-
silicon raw material and 0.1-2 wt% of a
sintering aid; carrying out ball milling,
drying and forming,conducting calcining in a 1500-to-1600 DEG C high-temperature furnace for 0.5-1 hour, firing the mixed raw materials to a
molten state, and conducting cooling to obtain a
molten silicon dioxide
raw material; b, crushing the
molten silicon dioxide raw material prepared in the step a, mixing the crushed molten
silicon dioxide raw material with an
alumina raw material according to a
molar ratio of Al2O3 / SiO2 of 3: 1, co-
grinding the mixed raw materials, adding a binding agent accounting for 4 wt% of the total weight of the raw materials, carrying out molding under a pressure of 80-150 MPa, carrying out calcining at 1550-1650 DEG C for 3-8 hours, and carrying out cooling to obtain the high-purity
mullite crystal material. According to the invention, molten
silicon dioxide is used as a siliconsource, the
sintering temperature for synthesizing the high-purity
mullite material is low, the addition amount of the
sintering aid is small, and columnar mullite and lamellar mullite crystals are formed; and the high-purity mullite material has the characteristics of low
impurity content,
high density and good high-temperature mechanical properties.