化工进展 ›› 2017, Vol. 36 ›› Issue (10): 3786-3793.DOI: 10.16085/j.issn.1000-6613.2017-0206

• 材料科学与技术 • 上一篇    下一篇

在高剪切结晶器中合成文石型纳米碳酸钙

杨超, 郭翠梨   

  1. 天津大学化工学院, 天津 300350
  • 收稿日期:2017-02-13 修回日期:2017-04-10 出版日期:2017-10-05 发布日期:2017-10-05
  • 通讯作者: 郭翠梨,研究员,主要从事催化剂、材料制备等研究.
  • 作者简介:杨超(1990-),男,硕士研究生,从事高剪切反应器应用与材料制备.E-mail:yangchao@tju.edu.cn.

Synthesis of aragonite CaCO3 nanoparticles in a high shear mixer

YANG Chao, GUO Cuili   

  1. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, China
  • Received:2017-02-13 Revised:2017-04-10 Online:2017-10-05 Published:2017-10-05

摘要: 在高剪切结晶器中,以Ca(OH)2-CO2为反应物系,磷酸和聚丙烯酰胺(PAM)为复合添加剂,成功合成了文石型纳米碳酸钙。采用X 射线衍射(XRD)和扫描电镜(SEM)表征了产物的晶体结构和形貌,探讨了高剪切结晶器转速和添加剂用量对碳酸钙晶型和粒径的影响。结果表明,在高剪切结晶器中制得的文石型纳米碳酸钙纯度为98.1%,平均直径为50nm;而且反应时间只是普通搅拌反应器的(1/6)~(1/3)。高剪切结晶器具有较好的微混合性能,在反应结晶过程中能有效调控结晶器内过饱和度分布等微环境,利于亚稳态的文石形成。磷酸和PAM复合添加剂对晶型和粒径的调控有重要的作用。磷酸与Ca(OH)2反应生成了羟基磷灰石,其作为晶种诱导文石异相成核;PAM对粒径减小有重要作用,能够阻止晶体沿着径向生长,使亚稳态的文石在溶液里稳定存在,防止粒子间的团聚。

关键词: 纳米粒子, 高剪切结晶器, 文石, 多相反应

Abstract: In the reaction system of Ca(OH)2-CO2,aragonite CaCO3 nanoparticles were prepared with the addition of phosphoric acid and polyacrylamide(PAM)in a high shear mixer (HSM)-aided crystallizer. The structure and morphology of products were characterized by XRD and SEM. The effects of shear rate and the amounts of additives on the polymorph and the size of CaCO3 have been studied. The results indicated that the crystalline purity of aragonite CaCO3 generated in the HSM-aided crystallizer achieved 98.1% and the average diameter was 50nm. Moreover,the reaction time in the HSM-aided crystallizer was only (1/6)~(1/3) of that in the traditional stirred tank crystallizer. HSM can realize sufficient micro-mixing,and it can control the microenvironment such as the distribution of supersaturation in the reactive crystallization,which is beneficial to the formation of metastable aragonite. The addition of H3PO4 and PAM plays an important role in controlling the polymorph and the size of aragonite CaCO3. H3PO4 can react with Ca(OH)2 to form hydroxyapatite which serves as heterogeneous nuclei. PAM can inhibit the crystal growth in radial direction and stabilize aragonite by preventing agglomeration in the solution.

Key words: nanoparticles, HSM-aided crystallizer, aragonite, multiphase reaction

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