The invention provides a method for removing
silicon in aluminum
oxide, and belongs to the field of aluminum
oxide production. The method comprises the following steps: carrying out primary desiliconization on
bauxite ore pulp, so that SiO2 in the
bauxite ore pulp is converted from a supersaturated metastable state into
sodium silicon slag precipitate, and obtaining primary desiliconized
slurry; performing secondary desiliconization on first mixed
slurry of the primary desiliconization
slurry and the blending liquid, so that
silicon minerals in the first mixed slurry form hydrated
sodium aluminosilicate, and secondary desiliconization slurry is obtained; carrying out
settling separation on the secondary desiliconized slurry with the set
solid content to obtain second mixed slurry; adding an additive into the second mixed slurry to carry out
tertiary desilicication so as to obtain
tertiary desilicication slurry; carrying out
solid-liquid separation on the
tertiary desilicication slurry to obtain decomposed
mother liquor; and performing low-temperature
decomposition and high-temperature
roasting on the
decomposition mother liquor to obtain aluminum
oxide. Therefore, high-quality aluminum oxide with the silicon content lower than 50 ppm is directly produced in the
Bayer process production process, and the production requirement for producing high-purity aluminum raw materials is met.