Thermal Behavior and Determination of the Heated Structure of 11? Anomalous Tobermorite by in situ X-ray Diffraction

• 作者: YAN Yu WANG Hejing
• 来源期刊: 地质学报（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: ORIGINAL ARTICLES
• 页码范围: 810-829
• 页数: 20页
• 语种: 英文

摘要

This article presents the thermal transitions of a tobermorite-bearing sample when heated from 30℃ up to 1200℃, both in vacuum and in static air, including tobermorite transforming to wollastonite, aragonite to calcite and calcite to lime. Characteristics obtained by in situ high temperature X-ray diffraction, field emission scanning electron microscopy and scanning transmission electron microscopy analyses jointly indicate that the investigated tobermorite is anomalous. The variations along the a, b, c axes and the volume changes of tobermorite with increasing temperature are described, and its thermal shrinkage coefficients therefore determined. The comparison between the refined structures at 30℃ and 800℃ demonstrates that the shrinkage degree (Δa/a0) along the a axis is higher than those (Δb/b0, Δc/c0) along the b and c axes. The wollastonite is formed in two ways: Tobermorite converting to wollastonite and lime reacting with quartz to form wollastonite.