用 MgSO4制备不同水合碳酸镁晶体及晶体转变过程  

Preparation and Crystal Transformation Process of Magnesium Carbonate Hydrate Using MgSO_4 as Raw Material

作　　者：杜娟[1,2] 陈镇[2] 吴玉龙[2,3] 杨明德[2] 党杰[2] 袁建军[1] 

机构地区：[1]天津科技大学,天津市海洋资源与化学重点实验室,天津300457 [2]清华大学核能与新能源技术研究院,北京100084 [3]清华大学,精细陶瓷北京市重点实验室,北京100084

出　　处：《硅酸盐学报》2012年第9期1321-1326,共6页Journal of The Chinese Ceramic Society

基　　金：国家“十一五”科技支撑计划重点项目(No.2008BAB35B05)资助

摘　　要：以MgSO4为原料,通过向MgSO4溶液中滴加(NH4)2CO3得到碳酸镁水合物。借助X射线衍射、扫描电子显微镜、差热分析及Raman光谱分析了转变过程中晶体组成和形态变化。研究发现,在25～45℃制备的产物均为单斜晶系、空间群为P21/n(14)的MgCO3 3H2O晶体;在50～60℃结晶产物存在由针状的MgCO3 3H2O晶体向单斜晶系、空间群为P21/c(14)的片状4MgCO3 Mg(OH)2 4H2O晶体的转变。从pH值变化和生长基元的形成对碳酸镁水合物晶体转变过程进行了分析。Magnesium carbonate hydrates were prepared via dropping （NH4）2CO3 solution using MgSO4 as a raw material. The sam- ples prepared were characterized by scanning electron microscopy, X-ray diffraction, differential thermal analysis and Raman spec- troscopy, respectively. The results show that the product prepared at 25-45 ℃ is MgCO3·3H2O crystal, belonging to monoclinic sys- tem and space group P21/n（14）. The crystal transformation occurs in the temperature range of 50 ℃ and 60 ℃. During the process, the crystal composition changes from MgCO3·3H2O to 4MgCO3·Mg（OH）2·4H2O （space group P21/c（14））. The morphology of the crystals varies from needle-like to sheet-like. The transformation process of crystal is correlated to the solution pH value and the growth units.

关 键 词：碳酸镁水合物 生长基元 晶体转变 晶体生长 

分 类 号：O784[理学—晶体学]