Sodium aluminate → Molecular sieve

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Reaction Steps

The thus obtained polymeric sodium silicate is used as a silicic acid source, to which is added an alkali aluminate, for example, sodium aluminate (a molar ratio of Na2O to Al2O3 1.5 - 3.0 : 1) in a molar ratio of SiO2 to Al2O3 of 1.0 - 2.0 : 1. Thereby, the sodium aluminate is bonded with polymeric sodium silicate by the lattice siloxane structure as a frame to produce sodium aluminosilicate, (1.0 - 2.0) SiO2.Al2O3.(2.0 - 1.0)Na2O. Here, part of sodium hydroxide is isolated according to an amount of aluminate ion bonded. Further, an amount of a water soluble magnesium salt, for example, magnesium chloride corresponding to the alkali amount of the sodium aluminosilicate is added in a molar ratio of MgO to Al2O3 of 1.0 - 2.0 : 1 to effect double decomposition. Thus, the desired magnesium aluminosilicate is obtained.

Provenance & Evidence