Type A is the representative molecular sieve of low silicon series, which contains three types such as 3A, 4A, 5A. The silica alumina ratio is near 1. The highest content of cation and exchanged power, Big porosity, large specific surface and smaller diameter of hole. It is mainly used in purification, desiccation, separation and the process of ion exchang. For instance, it is applied in the project of ethylene and propylene, production of oxyen, dehydration of ethylene, ion exchange in cleaning, dewaxing, production of ammonia, separating industiral gas and petrochemical industry.