碱式碳酸镁焙烧法制备多孔氧化镁晶体  

Preparation of porous MgO crystals with hydromagnesite roasting method

作　　者：邓凤 王余莲[1] 张一帆 李纪勋 关蕊 李克卿 苏峻樟 孙浩然 韩会丽 袁志刚[1] 苏德生 池云 DENG Feng;WANG Yulian;ZHANG Yifan;LI Jixun;GUAN Rui;LI Keqing;SU Junzhang;SUN Haoran;HAN Huili;YUAN Zhigang;SU Desheng;CHI Yun(School of Materials Science and Engineering,Shenyang Ligong University,Shenyang 110158,China;Liaoning Province Ultra High Power Graphite Electrode Material Professional Technology Innovation Center,Dandong 118100,China;Liaoning Dan Carbon Group Corporation Limited,Dandong 118100,China;Party School of the CPC Liaoning Provincial Commitee,Shenyang 110158,China)

机构地区：[1]沈阳理工大学材料科学与工程学院,辽宁沈阳110158 [2]辽宁省超高功率石墨电极材料专业技术创新中心,辽宁丹东118100 [3]辽宁丹炭科技集团有限公司,辽宁丹东118100 [4]中共辽宁省委党校,辽宁沈阳110004

出　　处：《中国粉体技术》2024年第2期138-150,共13页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:52374271;沈阳市科技局项目,编号:22-322-3-03;辽宁省重点研发计划项目,编号:2022JH2/101300111;沈阳市中青年科技创新人才支持计划项目,编号:RC220104;辽宁省教育厅项目,编号:LJKMZ20220588;辽宁省大学生创新创业训练项目,编号:S202210144002。

摘　　要：【目的】实现多孔MgO晶体的可控制备。【方法】以菱镁矿为镁源,采用水化碳化-低温水溶液法,热解Mg(HCO_(3))_(2)溶液合成平均直径为10.0μm、平均长度为50.0μm的多孔棒状碱式碳酸镁(4MgCO_(3)·Mg(OH)_(2)·4H_(2)O);通过焙烧法制备多孔MgO晶体,分别探讨焙烧温度、时间对前驱体4MgCO_(3)·Mg(OH)_(2)·4H_(2)O分解率、MgO物相组成和形貌的影响,探究4MgCO_(3)·Mg(OH)_(2)·4H_(2)O热分解机制。【结果】在焙烧温度为700℃、时间为3.0 h时,制得平均直径为20.0μm、平均长度为50.0μm、比表面积为76.12 m^(2)/g的介孔棒状MgO晶体;在4MgCO_(3)·Mg(OH)_(2)·4H_(2)O分解过程中,随着温度升高,结晶水失去,—OH的分离和C—O键断裂,4MgCO_(3)·Mg(OH)_(2)·4H_(2)O结构彻底崩塌,生成的MgO纳米片在高温下自组装成2种形貌的多孔棒状MgO,一种是纳米片全部覆盖的多孔棒,另一种是一端由纳米片覆盖,另一端光滑的多孔棒,此过程中晶格常数减小,晶粒直径由51.92 nm减小为11.28 nm。【结论】以菱镁矿为镁源可以实现多孔MgO晶体的可控制备。Objective To improve the efficient utilization of mineral resources and achieve the controlled preparation of porous magnesium oxide(MgO) crystals.Methods In this paper, magnesite was used as raw material and calcined at 750 ℃ for 3.0 h to produce light burned magnesium powder, and then the light burned magnesium powder was sifted to obtain powder with a particle size less than 75 μm. The powder was mixed with deionized water in a mass ratio of 1∶40, and heavy magnesium water was obtained by hydration carbonization method. The porous rod-like hydromagnesite(4MgCO_(3)·Mg(OH)_(2)·4H_(2)O) with an average length of 50 μm and an average diameter of 10.0 μm were successfully prepared by direct pyrolysis of heavy magnesium water using low-temperature aqueous solution without the incorporation of additional additives. Then using hydromagnesite as precursor, porous magnesium oxide crystals were prepared by direct roasting method. The effect of calcination time and temperature on the decomposition rate of the precursor hydromagnesite, as well as the resulting phase composition and microstructure of the magnesium oxide final product, was discussed. At the same time, the thermal decomposition mechanism of the precursor hydromagnesite during its transformation into magnesium oxide crystals was investigated.Results and Discussion The results show that: Neither the duration nor temperature of roasting has significant effects on the decomposition rate of precursor hydromagnesite, nor did they impact the phase composition and micro-morphology of the magnesium oxide crystals. However, two morphologies appeared roasted at of 700 ℃ for 3.0 h. The obtained magnesium oxide features mainly porous rod-like structure with an average diameter of 20.0 μm. A minor fraction comprises rod-like crystal, distinguished by a smooth surface at one end and a porous structure covering the other end. The mean diameter of the part with a smooth surface is 10.0 μm, while the mean diameter of the part covered by a porous structure is 20.0

关 键 词：菱镁矿 碱式碳酸镁 氧化镁 生长机制 

分 类 号：TB44[一般工业技术]