Application of Fe — Al — La composite oxide microsphere with CaO layer in treating wastewater containing high-concentration of fluorine

A kind of Fe - Al - La composite oxide microspheres coated with a delay water-soluble layer of CaO was prepared. It was used to treat wastewater containing high concentration of fluorine. When chemical precipitation, flocculation precipitation ended, the fluorine content in water was <;20 mg/L, the CaO layer of Fe - Al - La composite oxide microspheres is dissolved and Fe - Al - La oxide microspheres begin to adsorb fluorine. The amount of CaO added in industrial operation was as follows: C_F: C_Ca = 2.2:1.0 (mol ratio). Polymerized AlCl₃ wt 1.0%CaO, FeSO₄ wt 1.0% CaO, MgO wt 1.0% CaO, a certain amount of PAM, 0.1% CaO, and Fe - Al - La composite oxide microspheres with CaO layer were mixed together and added into wastewater. After being stirred for 1.2h, the concentration of F was <; 8mg/L. this shows that this method is a new F-removal process having many advantages.