Modification of Colloidal Silica with Sodium Aluminate

Abstract

Colloidal silica modified by sodium aluminate was examined. The particle size of Al-modified colloidal silica was slightly increased with increase of the sodium aluminate concentration, but colloidal silica may aggregate or gel under high concentration. Zeta potential was more negative and thermal stability was significantly improved through modification. The Al-modified colloidal silica was highly stable at pH 3-6.