PREPARATION METHOD OF LOW SODIUM OXIDIZED HEMATITE USING BY-PRODUCT OF BAYER PROCESS, COMPRISING DRYING, THERMAL DECOMPOSITION AND ACID TREATMENT OF RED MUD

摘要

PURPOSE: A method for preparing a low sodium oxidized hematite by using the by-product of Bayer process is provided, to obtain the oxidized hematite whose sodium (Na2O or Na2CO3) content is less than 1.0 wt% by using red mud. CONSTITUTION: The method comprises the steps of thermally decomposing the red mud molded into a spherical pellet, in air to prepare an active oxidized hematite; and removing Na+ from the active oxidized hematite by using an acid. Preferably the thermal decomposition is carried out at a temperature of 700-1,100 deg.C for 10-30 min; and the acid is an oxalic acid or an inorganic acid (preferably HCl or sulfuric acid). Preferably the acid aqueous solution has a concentration of 5-10 vol%, and the acid treatment is carried out at a temperature of 25-100 deg.C for 5-30 min.