Molecular sieve is amorphous silicate or silicon aluminate!

In a narrow sense, molecular sieve is amorphous silicate or silicon aluminate, made of silicon oxygen tetrahedron or alumina tetrahedron by oxygen bridge is linked together to form a molecular size (usually from 0.3 to 0.3 nm) of concreted complete cavity system, which are characteristic of molecular sieve. However, with the deepening of the molecular sieve synthesis and application research, the researchers found that the phosphorus aluminate salts molecular sieve, molecular sieve and the skeleton of elements (silicon or aluminum or phosphorus) can also Be composed of B, Ga, Fe, Mn, Cr, Ge, Ti, V, Co, Cu and zinc, Be replaced, the concreted complete cavity also can achieve more than 2 nm, the size of the molecular sieve can Be divided by skeleton elements silicon aluminum type molecular sieve, p type of molecular sieve and skeleton heteroatomic molecular sieve; According to the hole size, hole size less than 2 nm, 2 ~ 50 nm, and more than 50 nm molecular sieve respectively called microporous and mesoporous and macroporous molecular sieve. Because of the large aperture, become a good carrier of larger molecular reaction, but for amorphous mesoporous materials of hole wall, leading to the water thermal stability and thermal stability is not required for petrochemical industry application harsh conditions.

Due to the low contain electricity price big metal ion and ionic radius and combining state of the water, the water molecules in the heated continuously losing, but crystal skeleton structure remains the same, has formed many of the same size of the cavity, the cavity has many of the same diameter pores is linked together, these small cavity diameter size uniform, can channel diameter smaller than the molecular adsorption to the interior of the cavity, and channel than large molecules are excluded, so the molecules of different diameter size shape, the degree of different polarity molecules, the boiling point of different molecules, degree of saturation of different molecular separation, which have the function of the "screening" molecules, known as molecular sieve. The molecular sieve in metallurgy, chemical industry, electronics, petrochemical, natural gas and other widely used in industry.