(1. 北京科技大學(xué) 冶金與生態(tài)工程學(xué)院，北京 100083；
2. 中國(guó)科學(xué)院 過(guò)程工程研究所 綠色過(guò)程與工程重點(diǎn)實(shí)驗(yàn)室
濕法冶金清潔技術(shù)國(guó)家工程實(shí)驗(yàn)室，北京 100190；
3. 北京化工大學(xué) 化學(xué)工程學(xué)院，北京 100029)
摘 要: 以脫鋁赤泥和脫鋁粉煤灰為原料，采用水熱法制備硬硅鈣石，考察原料配比、液固比及反應(yīng)時(shí)間對(duì)硬硅鈣石生成及形貌的影響。結(jié)果表明：在220 ℃、鈣硅比為1.0時(shí)，脫鋁粉煤灰摻入量的增加、液固比的提高和反應(yīng)時(shí)間的延長(zhǎng)均促進(jìn)了硬硅鈣石的生成。最佳反應(yīng)條件為：脫鋁粉煤灰加入量大于總質(zhì)量40%、液固比35 mL/g、反應(yīng)時(shí)間9 h。在該條件下獲得了由直徑為25~50 nm，長(zhǎng)徑比大于20的硬硅鈣石單晶晶須纏繞而成的球形粒子。通過(guò)掃描電鏡(SEM)、透射電鏡(TEM)和背散射電子圖像(BSE)分析晶須生長(zhǎng)、成球機(jī)理及粒子內(nèi)部結(jié)構(gòu)，證實(shí)了球形粒子的中空結(jié)構(gòu)可能與反應(yīng)初期形成的前驅(qū)體包裹晶態(tài)SiO2有關(guān)。
關(guān)鍵字: 硬硅鈣石；脫鋁赤泥；脫鋁粉煤灰；晶須；球形粒子；水熱反應(yīng)
（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
