文献类型：期刊文献

英文题名：Mechanism of Magnesium's Influence on Calcium Carbonate Crystallization: Kinetically Controlled Multistep Crystallization

作者：Zhang, Jie[1];Dong, Chunhua[1];Sun, Yuzhu[1];Yu, Jianguo[1]

机构：[1]East China Univ Sci & Technol, Natl Engn Res Ctr Integrated Utilizat Salt Lake R, Meilong Rd 130, Shanghai 200237, Peoples R China

年份：2018

卷号：53

期号：8

外文期刊名：CRYSTAL RESEARCH AND TECHNOLOGY

收录：;EI(收录号：20183405725607);WOS:【SCI-EXPANDED(收录号:WOS:000441876600009)】；

基金：The authors would like to thank the financial support from Natural Science Foundation of China (NSFC, No. U1507105), National Sci-Tech Support Plan (No. 2015BAB10B01), National Key R&D Program (No. 2016YFC0401203), and China Scholarship Council (CSC, No. 201606740050).

语种：英文

外文关键词：amorphous calcium carbonate; FBRM; kinetics; prenucleation cluster; selective ion electrode

摘要：Crystallization of calcium carbonate under high concentration of magnesium (Mg/Ca > 5) follows a multistep pathway that is controlled by kinetics. There is a high concentration of calcium ions (supersaturated) that stably coexisted with the amorphous calcium carbonate and monohydrocalcite in our experiments. The authors propose that most of the calcium ions in the solution existed as the prenucleation cluster that had been stabilized by the hydrated magnesium ions. The dehydration free energy barrier of magnesium is higher than that of removing hydrated magnesium ions from the prenucleation cluster. Thereby, the prenucleation cluster slowly evolves into a more ordered structure by removing the hydrated magnesium ions, which is faster than the dehydration of magnesium. In addition, the crystallization via the agglomeration of the prenucleation clusters is one of the major pathways. However, before transforming into more ordered structure with less hydrated magnesium ions, prenucleation cluster was inactive in agglomeration. Thus, the oscillation of calcium concentration is observed in the continuous feeding crystallization reactor, due to the accumulation of active prenucleation cluster before rapid crystallization happened in the solution.