大颗粒磷钼酸铵制备与结晶动力学.pdf

第31卷第4期
无机化学学报
Vol 31 No4
2015年4月
CHINESE JOURNAL OF INORGANIC CHEMISTRY
789-797
大颗粒磷钼酸铵:制备与结晶动力学
黄云故刘珊阳卫军*
湖南大学化学化工学院,长沙410082)
摘要:通过缓慢滴加焦酸钾的硝酸溶液到钼酸铵溶液中制得了大颗粒礫钼酸铵(AMP)。研究了AMP的成核速率()与晶体生
长速率。与晶体生长速率相比成核速率的反应级数更高。最初,大颗粒磷钼酸铵的结晶过程处于相变反应控制的动力学区域,此
时溶液的过饱和生成速率比过饱和消除速率高。晶体线生长速率与溶液的过饱和度先增加后降低。在滴加中期,过饱和消除速
率增长到与其生成速率相当。在滴加后期,晶体成核速率快速增高,而晶体的线生长速率下降。晶体的成核速率成为过饱和消除
的唯一控制步骤。因此,AMP成核大部分是在首先接触到滴加液的局部溶液中完成的。
关键词:晶体生长:礫钼酸铵;X射线衍射;成核速率;动力学;晶体线生长速率
中图分类号:0611.4:0613.62
文献标识码:A
文章编号:1001-48612015)04-0789-09
DOI:10.11862/CJIC.2015.099
Large Particle Ammonium Molybdophosphate: Preparation and Crystallization Kinetics
HUANG Yun-jing LIU Shan YANG Wei-jun
College of Chemistry and Chemical Engineering, Hunan Uniuersity, Changsha 410082, China)
Abstract: Large particle ammonium molybdophosphate (AMP)was prepared by slowly dropping a nitric ac
solution of potassium pyrophosphate into an ammonium molybdate solution. The nucleation rate (G)and crystal
growth rate for AMP were studied. Compared with crystal growth, the nucleation has a higher reaction order
Initially, large particle AMP crystallizes in the kinetic region controlled by phase transfer reaction when the
rowing speed of supersaturation is higher than the removing speed. The crystal linear growth rate (L)and
supersaturation degree (A)of the solution increases first and decreases thereafter. In the medium dropping
stage, the increase in removing speed of supersaturation is the same as the growing speed. During the late
dropping stage, the nucleation rate rises rapidly when the crystal linear growth rate decreases and the nucleation
rate is the only control step for the removing speed of supersaturation. Therefore, the nucleation of AMP almost
completes In local solution as soon as meeting the nitrie acid solution
Key words: crystal growth; ammonium molybdophosphate; X-ray diffraction; nucleation rate; kinetics; crystal linear growth rate
0 Introduction
due to high partition coefficient, selective separation
factor and adsorption capacity 4. Since AMP is prone
Ammonium molybdophosphate (AMP), as a to being dissolved in alkaline solution and has a fine
heteropoly salt with Keggin structure, can highly powdery microcrystalline structure
selectively adsorb R, Cs,*and other alkali metal ions. permeability, it is not suitable for industrial column
It is also an excellent inorganic ion exchange material adsorption operation Therefore, the particle size of
收稿日期:2014-10-12。收修改稿日期;2015-0]-01。
中央高校基本科研业务费专项基金(No.107021?资助项目
通讯联系人。E-mal:wuyang@hnu.edu.cn