Rapid Zeolization of Potassic Rocks by Means of a Microwave‐Assisted Hydrothermal Method

Abstract

Potassic rocks are rapidly activated and converted to cancrinite (CAN) zeolites in NaOH solution via microwave-assisted hydrothermal (MH) method. The conditions of zeolization process via MH method are optimized, and the mechanism is illustrated. The phase transition process of potassic rocks is obtained as follows: decomposition of the potassic rocks!zeolite sodalite!zeolite CAN. In this process, the microwave exerts a reinforcement effect by generating the cleavage cracks on the surface of potassic rocks and accelerating the dissolution and crystallization processes. The synthesized zeolite CAN exhibits the maximum adsorption capacity of 6.5 mg g À 1 for methylene blue. In addition, the filtrate is further used to prepare linda type A (LTA) zeolites by conventional hydrothermal synthesis method. The synthesized zeolite LTA presents the cubic morphology with rounded corners, and its Ca 2 + ion exchange capacity could reach 335.6 mg CaCO 3 g À 1 .