Conversion of rice husk ash to zeolite beta

White rice husk ash (RHA), an agriculture waste containing crystalline tridymite and α-cristobalite, was used as a silica source for zeolite Beta synthesis. The crystallization of zeolite Beta from RHA at 150 °C in the presence of tetraethylammonium hydroxide was monitored by XRD, FTIR and 29Si MAS NMR techniques. It was found that zeolite Beta started to form after 12 h and the complete crystallization of zeolite Beta phase was achieved after 2 d. XRD, 29Si MAS NMR and solid yield studies indicate that the transformation mechanism of silica present in RHA to zeolite Beta involves dissolution of the ash, formation of an amorphous aluminosilicate after 6 h of crystallization, followed by dissolution in the mother liquor and final transformation to pure zeolite Beta crystals.