There are two kinds of zeolites: natural zeolite and synthetic zeolite. Most of the natural zeolite is formed by reacting volcanic tuff and tuffaceous sedimentary rocks in marine or lacustrine facies. More than 1000 kinds of zeolite ores have been found, 35 of which are more common, including clinoptilolite, mordenite, mordenite and zeolite. Mainly in the United States, Japan, France and other countries, China has also found a large number of mordenite and clinoptilolite deposits, Japan is the largest amount of natural zeolite mining countries. Due to the limitation of natural zeolite resources, zeolite has been widely used since 1950s.
The molecular sieves of commodities are usually classified by prefix numbers to classify the molecular sieves with different crystal structures, such as 3A, 4A and 5A zeolites. 4A is a table, a pore size of 4;. A type molecular sieve with Na+ denoted as Na-A, if the Na+ is K+ replacement, pore size is about 3 A, namely; 3A molecular sieve; such as Na-A 1/3 Na+ Ca2+ is more than about 5 a replacement aperture;, i.e. the 5A type molecular sieve.