Zeolite Syntheses from Superalkaline Reaction Mixtures

Abstract

The synthesis of faujasite-type zeolite from superalkaline reaction mixtures are described. The contribution shows the influence of component K2O added in the system Na2O-Al2O3-SiO2-H2O with H2O/(K2O + Na2O) = 13-15. The reaction course was investigated in the range K2O/(K2O + Na2O) from about 0.07 to 0.5. Under used conditions it is quite possible to isolate faujasite-type zeolite as a single crystalline phase. By means of IR spectroscopy, low SiO2/Al2O3 ratios from 2.0 to 2.1 in the faujasite framework have been indicated. The low SiO2/Al2O3 ratios are interpreted by a higher stability of the Si-O-Al- than the Si-O-Si- bond with increasing hydroxyl ion concentration.

Enclosure of Sodium Tetrahydroborate (NaBH4) in Solidified Aluminosilicate Gels and Microporous Crystalline Solids for Fuel Processing

“…Tetrahydroborate-sodalite nanoparticles were successfully synthesized even at lower temperature hydrothermal conditions (60°C) from high alkaline aluminosilicate gels and NaBH4 salt [22,23]. Preparation of basic hydrosodalite by this very simple method was first described by [53,54] during experiments on zeolite A crystallization at very low temperatures under superalkaline conditions. Fine tuning of this gel method by [55] also yielded basic-hydrosodalite nanoparticles.…”

Electrostatic Filter Ash from Silane Production as Silicate Substitute in Zeolite Chemistry

“…Therefore, FA conversion into zeolites was investigated by an energy and time efficient method under low temperature super alkaline conditions. This method was described first in the literature [18][19][20] for synthesis with gels obtained from pure chemicals. In a previous study, [16,17] this method was described as a suitable procedure for alkaline digestion of filtration residues from industrial waste water reconditioning.…”

“…Therefore 8 m NaOH was revealed, a concentration already used [18][19][20] for gel syntheses from pure chemicals at low temperature. The digestion periods 0.5 h, 1.0 h, and 1.5 h were selected to investigate of the time dependent alkaline reaction behavior of FA.…”

“…The alkaline digestion behavior of FA was examined in a reaction series with 8 m NaOH following the superalkaline conditions used for experiments [18][19][20] with common pure chemicals instead of residues. The dissolution kinetics was studied for the digestion times 0.5 h, 1.0 h, and 1.5 h at low temperature of 60°C.…”

Low Temperature Synthesis of Zeolites of the Faujasite Family (FAU-EMT) Using Industrial Mineral Waste (FR) from Silane Production

“…Temperatures in the range of 80˚C -90˚C were typically revealed to synthesize zeolites of structure type FAU [19]. Synthesis of zeolites hydrosodalite, zeolite NaA and zeolite NaX were first performed at temperatures at the 70˚C -40˚C range by using superalkaline conditions [20] [21] [22]. The authors inserted pure synthesis chemicals in their experiments.…”