(1. 北京科技大学 冶金与生态工程学院，北京 100083；
2. 中国科学院 过程工程研究所 绿色过程与工程重点实验室
湿法冶金清洁技术国家工程实验室，北京 100190；
3. 北京化工大学 化学工程学院，北京 100029)
摘 要: 以脱铝赤泥和脱铝粉煤灰为原料，采用水热法制备硬硅钙石，考察原料配比、液固比及反应时间对硬硅钙石生成及形貌的影响。结果表明：在220 ℃、钙硅比为1.0时，脱铝粉煤灰掺入量的增加、液固比的提高和反应时间的延长均促进了硬硅钙石的生成。最佳反应条件为：脱铝粉煤灰加入量大于总质量40%、液固比35 mL/g、反应时间9 h。在该条件下获得了由直径为25~50 nm，长径比大于20的硬硅钙石单晶晶须缠绕而成的球形粒子。通过扫描电镜(SEM)、透射电镜(TEM)和背散射电子图像(BSE)分析晶须生长、成球机理及粒子内部结构，证实了球形粒子的中空结构可能与反应初期形成的前驱体包裹晶态SiO2有关。
关键字: 硬硅钙石；脱铝赤泥；脱铝粉煤灰；晶须；球形粒子；水热反应
（1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083;
2. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Key Laboratory of Green Process and Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China;
3. College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China）
Abstract:The xonotlite was prepared by hydrothermal method using sub-molten salt red mud (SRM) and sub-molten salt fly ash (SFA) as raw materials, and the effects of ratio of raw materials, liquid-solid ratio and reaction time on the synthesis and morphology of the xonotlite were examined. The results show that the synthesis of xonotlite is promoted with the increase of doping amount of SFA incorporation, liquid-solid ratio and reaction time under the condition of 220 ℃ and n(CaO)/n(SiO2) of 1.0. The optimal conditions are as follows: doping amount of SFA greater than 40% of the total mass, liquid-solid ratio 35 mL/g and reaction time 9 h. Under such conditions, the spherical particles are formed by the winding of xonotlite single crystal whiskers with diameter of 25-50 nm, length-diameter ratio over 20 are synthesized. The mechanisms of the growth of xonotlite whisker, formation of spherical particles and the internal structure characteristics of the spherical particles were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and back-scattered electron imaging (BSE). The results show that the forming of hollow structure of the spherical particles is probably related to the wrapped crystalline state SiO2 by precursor formed in the initial reaction stage.
Key words: xonotlite; sub-molten salt red mud; sub-molten salt fly ash; whisker; spherical particle; hydrothermal reaction
