Synthesis of zeolite with paulingite structure

The work is concerned with studying the conditions of hydrothermal synthesis of zeolite with a paulingite structure and optimizing the procedure of its preparation. The effect of the synthesis temperature and duration, the stirring speed, and the pressure on the crystallization of paulingite from the gel of the composition 9SiO2: 1.0Al2O3: 0.6Na2O: 0.4K2O: 1.4 (TEA)2O: 0.3Na2SO4: 140H2O, where (TEA)2O is tetraethylammonium oxide, were studied. The results showed that the temperature and the accuracy of its maintenance during the hydrothermal treatment of the initial gels have the greatest influence on paulingite crystallization. The optimal conditions for the synthesis of a single-phase product with a paulingite structure during the shortest possible time (10 h) were determined: a temperature of 180°C, pressure of 20 × 102 kPa, a stirring speed of 1000 rpm, a heating rate of the initial gel of 2°C/min, and the accuracy of maintaining the predetermined temperature within ±0.1°C.