How long does it take to bake at 200°C to activate the molecular sieve?

How long does the activated molecular sieve need to be baked at 200 degrees? Preheat it in a muffle furnace at around 150 for 1 to 1.5 hours, and then heat it to 350 degrees and then wait for 3 to 5 hours. If it is processed at 550 degrees, it will take 3 hours. Heat intermittently, cool naturally to 100~200, then take it out of the oven and put it into a drying device (the drying device must be preheated to avoid cracking). Activated molecular sieves should be used immediately. How long is the activation time of molecular sieves and what is the suitable temperature?
1. In the petrochemical refining process, the regeneration temperature of ZSM-5 can reach 700-800°C, and heating to 500°C should be no problem.
2. The activation temperature of molecular sieve under normal pressure is 450°C, and the activation time is 3 hours; the vacuum activation temperature is 350°C, and the activation time is 3 hours. The activation time is short, and the impurities adsorbed in the molecular sieve cannot be completely separated, which affects the application.
After the molecular sieve is activated, it changes from light red and white to red. what happened?
1. Oxidation, acidification, denaturation, and surface corrosion all have this effect. Judging from the activation of molecular sieves in industrial production, a slight pink phenomenon is also very common. This phenomenon is often found in iron cans and is formed after being soaked in water. In physics, it means rust color. This is formed by ion exchange.
2. In fact, the color of some particles is similar to this at the beginning, that is, a little light red, but after being activated a few times, it becomes very red and there is no accumulation. The change at this time is very incomprehensible. The building said it was caused by iron ions, etc., but I did not come into contact with metal ions during the whole process (there may be contact, but theoretically the reagents used do not have metal ions, so there is a certain amount. But just like after discoloration, the monotony of the molecular sieve still exists, but Not sure if activation is diminished as usual.