碳酸镁结晶过程离子团簇与扩散成核机制  

Ionic clusters and diffusion nucleation mechanism during crystallization of magnesium carbonate

作　　者：任文芝 强伟丽 廉士俊 兰忠[1] REN Wenzhi;QIANG Weili;LIAN Shijun;LAN Zhong(Liaoning Key Laboratory of Clean Utilization of Chemical Resource,Institute of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]辽宁省化工资源清洁利用重点实验室,大连理工大学化学工程研究所,辽宁大连116024

出　　处：《无机盐工业》2022年第3期51-58,共8页Inorganic Chemicals Industry

基　　金：国家自然科学基金重点项目(51836002)。

摘　　要：理解离子的团簇演化成核机制可以更好地进行结晶过程的调控。基于分子动力学模拟研究了结晶温区、溶质离子浓度等对溶液结晶成核与生长过程的影响,并探讨了溶质离子的团簇演化规律。结果表明,溶质离子的扩散速率与物质结构和分子间作用力有关,并且与成核或晶界生长过程的团簇演化相互影响。在此研究范围内,溶质离子浓度一定(1.71 mol/L)时,388 K体系的成核与生长能力最强,是晶界引导无水碳酸镁生长、干扰镁离子和水分子结合的最佳温度,吸附在晶界的溶质离子分数为28.33%;一定温度下(298 K),溶质离子浓度为3.99 mol/L时最有利于晶体生长,吸附在晶界的溶质离子分数为32.14%,且该浓度起到了最佳的脱水效果,有利于形成无水碳酸镁。这为获得结晶良好、形貌均匀的无水碳酸镁等工艺技术提供了理论依据和指导。Understanding the nucleation mechanism of ion cluster evolution can better regulate the crystallization process.The effect of crystallization temperature zone and concentration on the nucleation and growth process of solution crystallization was studied based on molecular dynamics simulation,and the evolution of solute ion clusters was discussed.The results showed that the diffusion rate of solute ions was related to the material structure and intermolecular forces,and interacted with cluster evolution during nucleation or grain boundary growth.Within the scope of this study,at the certain solute ion concentration(1.71 mol/L),the system had the strongest nucleation and growth ability at 388 K,which was the best temperature for the grain boundary to guide the growth of AMC and interfere with the combination of Mg;and H;O,and the ratio of solute ions adsorbed on the grain boundary was 28.33%.At the certain temperature (298 K),the ion concentration of 3.99 mol/L was the most conducive to crystal growth.Under this concentration,the ratio of solute ions adsorbed on the grain boundary was32.14%,and it had the best dehydration effect,which was beneficial to formate anhydrous magnesium carbonate.It provided theoretical basis and guidance for the technological process of obtaining anhydrous magnesium carbonate with good crystallization and uniform morphology.

关 键 词：团簇演化 成核与生长 分子动力学模拟 碳酸镁溶液 晶体表面 

分 类 号：TQ174[化学工程—陶瓷工业]