刘珈伊1,王余莲1,2,时天骄1,徐 昊1,张夏翔3,李 闯1,袁志刚1
（1.沈阳理工大学 材料科学与工程学院,辽宁 沈阳 110159;2.矿物加工科学与技术国家重点实验室,北京 100160;3.湖南大学 材料科学与工程学院,湖南 长沙 410082）
DOI：10.13732/j.issn.1008-5548.2021.01.005
收稿日期：2020-06-26，修回日期：2020-09-21，在线出版时间：2020-11-02 10:42。
基金项目：国家自然科学基金，编号:51804200；辽宁省教育厅高校科研基金，编号:LG201927; 矿物加工科学与技术国家重点实验室开放基金资助项目，编号：BGRIMM-KJSKL-2019-14；辽宁省科技厅博士启动基金项目，编号:20180540104。
第一作者简介：刘珈伊(1995—)，男(满族)，硕士研究生，研究方向为菱镁矿法制备微纳米碳酸镁系化合物基础研究。E-mail:liujiayizz07@163.com。
通信作者简介：王余莲(1986—)，女，博士，副教授，硕士生导师,研究方向为矿物材料的制备及应用研究。E-mail:xinxinwyl@163.com。
摘要：采用菱镁矿为原料，在无水乙醇辅助下，经水化、碳化、热解等过程，在较低温度(55℃)下制备碱式碳酸镁晶体(4MgCO3·Mg(OH)2·4H2O);采用X射线衍射仪(XRD)和扫描电镜(SEM)表征产物物相结构和微观形貌;研究热解时间、无水乙醇添加量、前驱溶液pH值以及无水乙醇加入时间对产物物相组成和形貌的影响;初步探讨无水乙醇辅助下碱式碳酸镁生长机理。结果表明:热解时间、无水乙醇添加量、前驱溶液pH值以及无水乙醇加入时间对4Mg CO3·Mg(OH)2·4H2O微观形貌和尺寸均起到调节作用;制备出平均直径为2.3μm、形貌呈玫瑰花苞状的4MgCO3·Mg(OH)2·4H2O的最佳条件为:热解时间为105 min、无水乙醇与Mg(HCO3)2溶液体积比为1∶2、前驱溶液pH值为10±0.05，此时无水乙醇加入时间对晶体无显著影响;加入无水乙醇辅助碱式碳酸镁生长过程，不仅可以减少反应所需能量，还可以形成致密度较好的双电层保护膜吸附在晶体表面，促进新核形成，加快MgCO3·3H2O向4MgCO3·Mg(OH)2·4H2O的转变速率。
关键词：无水乙醇；菱镁矿；碱式碳酸镁晶体；低温直接法
Abstract：Basic magnesium carbonate crystals (4MgCO3·Mg(OH)2·4H2O) were prepared from magnesite with the aid of anhydrous ethanol through hydration,carbonization,pyrolysis and other processes at a low temperature (55 ℃) ． The phase structure and microstructure of the products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of pyrolysis time,addition amount of anhydrous ethanol,pH of precursor solution and addition time of anhydrous ethanol on phase composition and morphology of products were studied. The growth mechanism of basic magnesium carbonate assisted by anhydrous ethanol was investigated. The results show that the microstructure and size of 4MgCO3·Mg (OH)2·4H2O are regulated by pyrolysis time,amount of anhydrous ethanol,pH of precursor solution and time of anhydrous ethanol addition. The optimum conditions for the preparation of 4MgCO3·Mg (OH)2·4H2O with the mean diameter of 2. 3 μm and the morphology of rose bract are as follows: pyrolysis time of 105 min,volume ratio of anhydrous ethanol to Mg (HCO3)2 solution of 1∶2,and pH value of the precursor solution of 10 ± 0. 05. At this time,the addition amount of anhydrous ethanol has no significant effect on the crystal. The addition of anhydrous ethanol to assist the growth process of basic magnesium carbonate can not only reduce the energy required by the reaction,but also form a dense double electric protective film which can be adsorbed on the crystal surface,promote the formation of new nucleus and accelerate the conversion rate of MgCO3·3H2O to 4MgCO3·Mg (OH)2·4H2O.
Keywords：anhydrous ethanol; magnesite; basic magnesium carbonate crystal; low temperature direct method
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