725℃煅烧后托贝莫来石的结构和表面形貌变化(英文)

Structure and Morphology Transition of Tobermorite after Calcined at 725 ℃

利用微米尺度、无定形二氧化硅与氧化钙制备层间距d(002)为1.13 nm的托贝莫来石,研究了托贝莫来石高温煅烧过程中的结构变化和在725℃时的微结构变化规律。结果表明:725℃煅烧2 h后,部分托贝莫来石形成类单斜链状的硅灰石结构(结晶态)和脱羟基托贝莫来石(无定形态);这种无定型的亚稳状态结构的外貌和托贝莫来石的晶体外貌相似,都是针状、片状的晶体,和大量由片状与针状堆积形成的颗粒状结构;在725℃煅烧温度下,部分微米、亚微米尺度的托贝莫来石转变为单斜链状的硅灰石结构。

Tobermorite with basal spacing (d(002)) of 1.13 nm was synthesized with submicron-sized amorphous silicon dioxide and calcium oxide. The structure and morphology changes of tobermorite calcined at 725℃for 2 h were investigated. The results show that dehydroxylation tobermorite and monoclinic α-CaSiO3 crystals appear after calcination. The dehydroxylation tobermorite is amorphous, disordered and metastable. The morphology of calcined tobermorite is similar to that of uncalcined tobermorite, i.e., needle-like and lamellar, due to the lamellar twining and accumulative generation of the particles. Some submicron-sized tobermorite crystals transform into monoclinicα-CaSiO3 crystals after calcination at 725℃for 2 h.