柠檬酸钠辅助三水碳酸镁合成无水碳酸镁晶体及其机制  

Sodium citrate-assisted synthesis of anhydrous magnesium carbonate crystals from magnesium carbonate trihydrate and its mechanism

作　　者：张一帆 王余莲[1] 孙浩然 李纪勋 关蕊 邓凤 李孟强 ZHANG Yifan;WANG Yulian;SUN Haoran;LI Jixun;GUAN Rui;DENG Feng;LI Mengqiang(Shcool of Materials Science and Engineering,Shenyang Ligong University,Shenyang 110159,China;China Magnesite&Material Association,Beijing 100036,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110159 [2]中国菱镁行业协会,北京100036

出　　处：《中国粉体技术》2024年第6期41-49,共9页China Powder Science and Technology

基　　金：国家自然科学基金项目,编号:52374271;辽宁省重点研发计划-应用基础研究项目,编号:2022JH2/101300111;沈阳市科技局项目,编号:22-322-3-03;沈阳市中青年科技创新人才支持计划项目,编号:RC220104;辽宁省教育厅面上项目,编号:LJKMZ20220588。

摘　　要：【目的】探究柠檬酸钠在三水碳酸镁合成无水碳酸镁晶体过程中的影响。【方法】以轻烧氧化镁为初始原料,通过水化碳化法获得长径比为30的棒状三水碳酸镁。以此为前驱体,柠檬酸钠为添加剂,采用水热法制备无水碳酸镁,探究水热温度、水热时间、添加剂含量对产物物相组成和微观形貌的影响及其形成机制。【结果】水热温度为190℃,水热时间为13 h,柠檬酸钠添加量(质量分数)为10%~30%,可获得物相均一、表面光滑、形状均匀、平均直径为3~5μm的棱柱状无水碳酸镁晶体;在水热反应中,柠檬酸根离子对镁离子具有较强的络合作用,钠离子较镁离子拥有更高的水合能力,导致碱式碳酸镁的形成受到抑制,得到另一种中间产物碳酸氧化镁,无水碳酸镁晶体的生长方式与形貌发生改变。【结论】三水碳酸镁在柠檬酸钠的影响下制备得到棱柱状无水碳酸镁。Objective Researchers typically use solid precursors such as nesquehonite,magnesium oxide,and magnesium oxalate to prepare MgCO_(3).However,these methods require stringent experimental conditions and specialized equipment,limiting their practicality.This paper investigated the preparation of nesquehonite from lightly burned magnesium oxide and the subsequent synthesis of anhydrous magnesium carbonate.The effects of sodium citrate concentration,citric acid concentration,hydrothermal tem perature,and hydrothermal time on the microscopic morphology and phase composition of the product were discussed.The formation mechanism of prismatic anhydrous magnesium carbonate in a sodium citrate-magnesium trihydrate system was explored.Methods Lightly burned magnesium oxide was first mixed with water at a mass ratio of 1∶30 and hydrated in a water bath at 90℃for 2 h to obtain Mg(OH)2.Carbon dioxide gas was then introduced at a fixed rate for 1h to produce heavy magnesium water(Mg(HCO_(3))2).The obtained water was subsequently pyrolyzed at 55℃for 2 h.After suction filtration,the filter cake was dried at 50℃ for 20 h to obtain white powder nesquehonite(MgCO_(3)·3H_(2)O).Finally,MgCO_(3)·3H_(2)O was mixed with deionized water at a mass ratio of 1∶30,and sodium citrate was added at concentrations ranging from 5%~50%.The mixture was stirred evenly,placed in a polytetrafluoroethylene liner,and reacted at temperatures within 110~190℃for 3~13 h to obtain MgCO_(3).Results and Discussion When the hydrothermal time was extended to 13 h,prismatic anhydrous magnesium carbonate crystals with smooth surface,good dispersion,and an average diameter of 2μm were produced.Increasing the hydrothermal temperature to 190℃ resulted in diamond-shaped anhydrous magnesium carbonate crystals with uniform morphology,consistent size,and average particle sizes of 3~5μm.With the increase of sodium citrate concentration,the particle size of the obtained anhydrous magnesium carbonate decreased.With a hydrothermal temperature of 190℃,hydroth

关 键 词：碳酸镁 水热法 柠檬酸钠 生长机制 

分 类 号：TQ32.2[化学工程—合成树脂塑料工业] TB4[一般工业技术]