Industrial preparation method of superstable Y-type molecular sieve

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Industrial preparation method of superstable Y-type molecular sieves: Synthesis of NaY. The synthesis of NaY employs an efficient and low-emission process as well as a hydrothermal synthesis method using a guiding agent. For the washing of NaY molecular sieves by ion exchange, a belt filter is used to remove the mother liquor, followed by ion exchange using a 10% ammonium sulfate solution; thereafter, deionized water is used to wash away the exchanged Na+ ions and excess ammonium sulfate. After spray drying in a single calcination step, it is calcined for 3–4 hours in a water vapor atmosphere with the atmosphere temperature controlled, to promote aluminum removal and silicon supplementation as well as to move the Na+ ions in the small cages to exchangeable positions. Double-stage filtration and washing: Rare earth and ammonium sulfide solutions are added to the molecular sieve in a specific order and ratio; the pH value is adjusted using dilute sulfuric acid, the mixture is kept at a temperature of over 90°C for 60 minutes, followed by filtration and washing.