FBRM在线研究三水碳酸镁在电解质溶液中的二次过程  

On-line FBRM Investigation of Secondary Processes of Nesquehonite in the Electrolyte Solutions

作　　者：杨晨[1] 宋兴福[1] 李树民 孙泽[1] 孙淑英[1] 于建国[1] 

机构地区：[1]国家盐湖资源综合利用工程技术研究中心,华东理工大学资源与环境工程学院,上海200237 [2]青海盐湖工业股份有限公司,青海格尔木816000

出　　处：《高校化学工程学报》2013年第4期701-707,共7页Journal of Chemical Engineering of Chinese Universities

基　　金：上海自然科学基金(09ZR147900);中央高校基本科研业务费专项基金;新世纪优秀人才(NCET-08-0776);上海市重点学科建设项目(B506)

摘　　要：实验采用聚焦光束反射测量仪(FBRM)在线监测三水碳酸镁在电解质溶液中颗粒弦长和弦粒数变化趋势,结合扫描电镜(SEM)和粉末晶体衍射(XRD)表征形貌和晶型,考察了介质对三水碳酸镁二次过程的影响。实验结果表明:在NaCl和Na2CO3溶液中二次过程不显著,对三水碳酸镁形貌和尺寸无明显影响;在MgCl2溶液中三水碳酸镁尺寸增大。理论计算表明,对于三水碳酸镁的二次过程,Ostwald熟化可以忽略,结合MgCO3.3H2O特定晶体结构和产物形貌分析,表明MgCl2可以促进三水碳酸镁的聚结,使颗粒形成束状形貌;实验条件下颗粒弦长增长率达到20%以上,并且随氯化镁浓度的升高先增大后减小。三水碳酸镁聚结主要是弦长20μm以下颗粒的行为,聚结使得20μm以上颗粒数量和尺寸增加。On-line FBRM（Focused Beam Reflectance Measurement） was employed to monitor the change trends of particle chord length（CL） and counts per second（CPS）.Scanning electron microscopy（SEM） and powder diffraction（XRD） were used to characterize sample morphology and crystal form.Based on these,the secondary processes of nesquehonite in electrolyte solutions were investigated.Experimental results show that： NaCl and Na2CO3 have no significant effects on the nesquehonite secondary processes.Nesquehonite particles become larger in MgCl2 solution.Theoretical calculations show that the Ostwald ripening is not obvious in the secondary processes of nesquehonite.Based on the analysis of the nesquehonite structure and the products morphology,it was found that the MgCl2 greatly promotes the aggregation of nesquehonite crystals.The morphology of nesquehonite is transferred from the rod-like to the bundle-like structure by aggregation.Under the experimental conditions,the chord length increases more than 20% and it firstly increases and then decreases with the increase of MgCl2 concentration.The aggregation occurrs among those particles with the chord length below 20 μm.The aggregation leads to the increase in particle number and size of particles with the chord length above 20 μm.

关 键 词：三水碳酸镁 FBRM 二次过程 电解质 聚结 

分 类 号：TQ115[化学工程—无机化工]