Method for removing sodium in preparation of high-purity alumina

The invention discloses a method for removing sodium in a preparation of high-purity alumina. The method comprises the steps of purifying, secondary purifying, washing, drying, secondary washing and drying again. The method specifically comprises the following steps of: grinding aluminium hydroxide with high sodium content to be less than or equal to 500mu m, stirring and washing for 2-3 times in thermostatic water bath with temperature being 50-55 DEG C by utilizing a sodium removing agent I to obtain pure aluminium hydroxide; washing the purified pure aluminium hydroxide with water till pH value is 7.0-7.5, drying and dehydrating; adding a sodium removing agent II to the washed and dried aluminium hydroxide, and stirring and washing for 2-3 times in the thermostatic water bath with temperature being 30-50 DEG C; and washing the aluminium hydroxide which is purified for the second time by utilizing pure water with temperature being 30-50 DEG C, drying, dehydrating and transforming the washed aluminium hydroxide to fluffy ultralow sodium aluminium hydroxide. The method has the advantages of convenience, conciseness, no pollution and good sodium-removing effect.