Influence of iron on crystallization behavior and thermal stability of the insulating materials - porous calcium silicates

Sonja Haastrup, Donghong Yu, Yuanzheng Yue

Research output: Contribution to book/anthology/report/conference proceedingConference abstract in proceedingResearch

Abstract

The properties of porous calcium silicate for high temperature insulation are strongly influenced by impurities. In this work we determine the influence of Fe3+ on the crystallization behavior and thermal stability of hydrothermally derived calcium silicate. We synthesize porous calcium silicate with Ca/Si molar ratio of 1, to which Fe2O3 is added with Fe/Si molar ratios of 0.1, 0.5, 0.7, 1.0, and 1.3%. Structure and morphology of the porous calcium silicate, with different iron concentrations, are investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). FTIR measurements reveal a pronounced decrease in the number of Q3 sites in the calcium silicate with an increase of Fe3+, and thereby lower the crystal fraction of xonotlite (Ca6Si6O17(OH)2) phase, and increase the crystal fractions of tobermorite(Ca5Si6O16(OH)2·4H2O) and calcite (CaCO3) phases, as confirmed by XRD analysis. The thermal stability and compressive strength of the calcium silicates are seriously influenced by the changes of their crystal structure. Linear shrinkage of the reference sample is 1.3% at 1050°C, whereas the sample with Fe/Si =1.0% does by 30.4%. In conclusion, the presence of Fe3+ modifies the crystal structure of porous calcium silicates, leading to a significant shrinkage in these materials.

Original languageEnglish
Title of host publication12th Pacific Rim Conference on Ceramic and Glass Technology
Publication date21 May 2017
Article numberPACRIM-S11-026-2017)
Commissioning bodySkamol A/S
Publication statusPublished - 21 May 2017
Event12th Pacific Rim Conference on Ceramic and Glass Technology - Hilton Waikoloa Village, Waikoloa, United States
Duration: 21 May 201726 May 2017
http://ceramics.org/meetings/pacrim12

Conference

Conference12th Pacific Rim Conference on Ceramic and Glass Technology
LocationHilton Waikoloa Village
Country/TerritoryUnited States
CityWaikoloa
Period21/05/201726/05/2017
Internet address

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