TY - JOUR

T1 - The Hydrothermal Synthesis of Sulfate Cancrinite (SO4-CAN)

T2 - Relations between Si-Al Sources and Crystal Quality

AU - Buhl, Josef Christian

AU - Petrov, Valeriy

N1 - Acknowledgements: The authors gratefully acknowledge Dr. M. Fechtelkord from Ruhr-Universität Bochum for performing the29Si and27Al MAS NMR measurements and R.-M. Klatt, Institute of Soil Science, Leibniz Un-versität Hannover, for the BET measurements. The authors gratefully acknowledge the very helpful recommendations of the two anonymous reviewers.

PY - 2019/11/15

Y1 - 2019/11/15

N2 - Sulfate cancrinite (SO4-CAN) Na8[AlSiO4]6(SO4)(H2O)n (2.6 < n < 3.2) was synthesized under hydrothermal conditions at 200 °C and 48 hours. Three different Si-Al sources were inserted: (a) kaolinite (K), (b) a gel of sodium-waterglass and sodium aluminate (G), and (c) an oxide mixture of cristobalite and corundum (CK). The products were characterized by X-ray powder diffraction (XRD), 29Si and 27Al MAS NMR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS) and BET surface area analysis as well as simultaneous thermoanalysis (TG-DTA). Mostly nanocrystals of platelet habit and dimensions smaller than 100 nm (beside a very few larger crystals) were observed from K. In contrast the gel (G) yielded to cancrinites with typical rod-like morphology and dimensions of 100 × 500 nm. Large prismatic cancrinites up to 5 μm width and 10 μm length were observed from the oxide mixture CK. Furthermore the transition kinetics of the cancrinites into nosean was investigated at a temperature of 1000 °C under open conditions. This process was already complete after 1 hour for the nanocrystals from K but needed 10 hours for the nanocrystals from G and the microcrystals from CK. The relations between the individual Si-Al source and the crystal properties like size, habit, and thermal transition kinetics were discussed.

AB - Sulfate cancrinite (SO4-CAN) Na8[AlSiO4]6(SO4)(H2O)n (2.6 < n < 3.2) was synthesized under hydrothermal conditions at 200 °C and 48 hours. Three different Si-Al sources were inserted: (a) kaolinite (K), (b) a gel of sodium-waterglass and sodium aluminate (G), and (c) an oxide mixture of cristobalite and corundum (CK). The products were characterized by X-ray powder diffraction (XRD), 29Si and 27Al MAS NMR spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDXS) and BET surface area analysis as well as simultaneous thermoanalysis (TG-DTA). Mostly nanocrystals of platelet habit and dimensions smaller than 100 nm (beside a very few larger crystals) were observed from K. In contrast the gel (G) yielded to cancrinites with typical rod-like morphology and dimensions of 100 × 500 nm. Large prismatic cancrinites up to 5 μm width and 10 μm length were observed from the oxide mixture CK. Furthermore the transition kinetics of the cancrinites into nosean was investigated at a temperature of 1000 °C under open conditions. This process was already complete after 1 hour for the nanocrystals from K but needed 10 hours for the nanocrystals from G and the microcrystals from CK. The relations between the individual Si-Al source and the crystal properties like size, habit, and thermal transition kinetics were discussed.

KW - CAN and SOD

KW - Nano- and microcrystals

KW - Phase transitions

KW - Si-Al source

KW - Sulfate enclathrated zeolites

UR - http://www.scopus.com/inward/record.url?scp=85074848933&partnerID=8YFLogxK

U2 - 10.1002/zaac.201900126

DO - 10.1002/zaac.201900126

M3 - Article

AN - SCOPUS:85074848933

VL - 645

SP - 1229

EP - 1239

JO - Zeitschrift fur Anorganische und Allgemeine Chemie

JF - Zeitschrift fur Anorganische und Allgemeine Chemie

SN - 0044-2313

IS - 21

ER -