文献类型：期刊文献

中文题名：水化时间和温度对半水硫酸钙晶须水化过程的影响

英文题名：Effects of Hydration Time and Temperature on Hydration Process of Calcium Sulfate Hemihydrate Whiskers

作者：刘天杰[1];范浩[1];许妍霞[1];宋兴福[1];于建国[1]

机构：[1]华东理工大学国家盐湖资源综合利用工程技术中心,上海200237

年份：2018

卷号：44

期号：1

起止页码：9

中文期刊名：华东理工大学学报（自然科学版）

外文期刊名：Journal of East China University of Science and Technology

收录：CSTPCD;;Scopus;北大核心:【北大核心2017】；CSCD:【CSCD_E2017_2018】；

基金：国家高技术研究发展("863")计划(2011AA06A107);青海省科技项目(2015-GX-Q19A)

语种：中文

中文关键词：半水硫酸钙晶须;水化时间;水化温度;水化机理

外文关键词：calcium sulfate hemihydrate whiskers; hydration time; hydration temperature; hydration mechanism

摘要：对水热法产物半水硫酸钙晶须水化过程进行了研究,重点考察了水化时间和温度对晶须水化过程的影响。结果表明,在水化温度为25~90℃范围内,水化产物中半水硫酸钙晶须含量随着水化时间的增加而减少,最终全部转化为片状、薄板状或者块状二水硫酸钙;随着水化温度的增加,水化诱导期延长,特别是在90℃时,半水硫酸钙晶须可稳定存在60min;根据水化产物观测结果以及物相组成分析发现,水化机理主要分为水化诱导期、半水硫酸钙晶须溶解以及二水硫酸钙重结晶3部分。
The hydration process of calcium sulfate hemihydrate （HH） whiskers by hydrothermal method was studied. Investigation mainly focused on the influence of hydration time and temperature on the hydration process of HH whiskers, and the determination of the hydration time and temperature on which HH whiskers could be relatively stable. The results showed that HH whiskers eventually transferred to flake, sheet, or lump calcium sulfate dihydrate （DH） with the time increasing at the hydration temperature within 25-90 ℃. With the increase of hydration temperature, the hydration induction period extended. Especially at 90 ℃ , the hydration induction period of HH whiskers increased significantly from 3 min at 60 ℃ to 60 min at 90 ℃. Therefore, the hydration of whiskers could be suppressed by rapid dehydration above 90 ℃. According to the observation results of hydration products and phase composition analysis, the hydration mechanism is mainly divided into three processes, the hydration induction period, the dissolution of HH whiskers, and the recrystallization of the calcium sulfate dehydrate. That is to say that there is a period of the hydration induction during the process of the hydration process of HH whiskers. When the whiskers contact with water, the active Ca^2＋ ions on its surface perform hydroxylation reaction with water. Then the hydroxyl groups on the whisker surface contact with water molecules by hydrogen bonding, and the water molecules are adsorbed on the surface of the whiskers. With the increase of hydration time, the water molecules will intrude into the lattice body and destroy the crystal structure, resulting in the break of the whiskers. With the fracture of HH whisker crystal structure,the Ca^2＋ and SO4 ions spread to the solution which accelerates the dissolution of HH whiskers. With the continuous precipitation and growth of DH, the further dissolution of HH whiskers is accelerated,until all HH whiskers are transferred to flake or thin plate DH crystals.