Effects of Pressured Steaming on the Migration of La3+ Ions and the Performance of As-Prepared LaY Zeolite

As a novel method, LaY zeolites were prepared by liquid rare earth ion exchange and further subjected to steaming under different pressures. The obtained LaY zeolites were investigated by detailed physic-chemical characterizations and catalytic cracking performance. It has been indicated that La3+ ions migrated into sodalite cages much more easily due to the steaming calcination with increased pressure at 500 °C. The pressured steaming improved the hydrothermal stability and the acidic stability of the LaY zeolite, resulting in a much higher catalytic cracking activity. After hydrothermal aging with 100% steaming at 800 °C for 17 h, the obtained LaY zeolite exhibits a much higher conversion and yield of gasoline and a lower coke yield than those of conventional LaY.