河北工业大学李雲团队报道了用Mg²⁺浓缩海水盐水可控合成均匀小粒径MgCO₃，制备环氧树脂复合材料和高纯MgO。相关研究成果发表在2025年1月7日出版的《颗粒学报》。

无水碳酸镁（MgCO₃）粒径大且不均匀，严重制约了其应用范围和性能。

该文中，研究人员提出了一种可控且成本效益高的策略，在没有晶体改性剂的情况下，从Mg²⁺浓海水盐水中合成均匀的小尺寸MgCO₃。在此过程中，将固体NaOH直接加入Mg²⁺浓海水盐水中，以完全快速地将Mg²⁺转化为氢氧化镁（Mg（OH）₂）纳米粒子。

这些纳米颗粒重新分散在水中形成胶体系统，其中Mg（OH）₂纳米颗粒与尿素水热反应，获得均匀的小尺寸MgCO₃颗粒。研究人员系统研究了反应温度、反应时间和镁离子与尿素的摩尔比，对MgCO₃合成的影响。在高度分散和稳定的胶体体系中，Mg（OH）₂纳米粒子可以通过吸引游离水，对尿素的水解速率产生有效和持续的阻滞作用，从而可控地释放NH₄⁺、CO₃^2-和Mg²⁺。

该研究提出了一种实现均匀小尺寸MgCO₃颗粒可控合成的简单方法，并证明了使用MgCO₃作为提高聚合物性能的理想填料，以及生产高纯度MgO的理想前体的可行性。

附：英文原文

Title: Controllable synthesis of uniform small-sized MgCO3 from Mg2+ concentrated seawater brine for the preparation of epoxy resin composite and high purity MgO

Author: Shuo Yan, Hongfei Guo, Dapeng Zhang, Yun Li, Jilin Cao

Issue&Volume: 2025/01/07

Abstract: The large and uneven grain size of anhydrous magnesium carbonate (MgCO3) seriously restricts its application ranges and performances. In this study, we proposed a controllable and cost-effective strategy to synthesize uniform small-sized MgCO3 from Mg2+ concentrated seawater brine in the absence of crystal modifiers. In this process, solid NaOH was directly added to Mg2+ concentrated seawater brine to completely and rapidly convert Mg2+ to magnesium hydroxide (Mg(OH)2) nanoparticles. These nanoparticles are redispersed in water to form the colloidal system, where Mg(OH)2 nanoparticles hydrothermally reacts with urea to obtain uniform small-sized MgCO3 particles. The influence of reaction temperature, reaction time, and the molar ratio of magnesium ions to urea on the synthesis of MgCO3 is systematically investigated. In the highly-dispersed and stable colloidal system, Mg(OH)2 nanoparticles could exert an effective and sustained retarding effect on the hydrolysis rate of urea by attracting free water, resulting in the controllable release of NH4+, CO32, and Mg2+. This study presents a simple route to realize the controllable synthesis of uniform small-sized MgCO3 particles, and demonstrates the feasibility of using MgCO3 as an ideal filler for enhancing the performance of polymers as well as an ideal precursor for high-purity MgO production.

DOI: 10.1016/j.partic.2024.12.012

Source: https://www.sciencedirect.com/science/article/abs/pii/S1674200125000094