氢氧化镧中共存物碳酸镧含量的测试方法探讨

Discussion on determination method of coexisting lanthanum carbonate in lanthanum hydroxide

分别采用X射线衍射仪(XRD)和同步热分析仪(TG-DSC)对含有不同质量分数八水合碳酸镧的氢氧化镧样品的相结构和分解温度进行了表征,探讨了特征衍射峰强度以及热分析过程中样品的失重量与八水合碳酸镧含量之间的关系,并从中计算出不同分析方法测试八水合碳酸镧含量的理论检出限。结果表明,针对本试验所用原材料,XRD可以检测出氢氧化镧中存在的0.25%的八水合碳酸镧,理论检出限为0.72%;而TG-DSC可以检测出氢氧化镧中存在的1%的八水合碳酸镧,理论检出限为2%,采用XRD方法的测试结果优于TG-DSC法的测试结果。

The phase structure and decomposition temperature of lanthanum hydroxide samples containing different mass fractions of lanthanum carbonate octahydrate were characterized by X-ray diffraction(XRD)and simultaneous thermal analyzer(TG-DSC),respectively.The relationship between the characteristic diffraction peak intensity as well as thermal weight loss of sample and lanthanum carbonate octahydrate content was discussed.The theoretical detection limits of lanthanum carbonate octahydrate in different analytical methods were calculated.The results showed that 0.25%lanthanum carbonate octahydrate in lanthanum hydroxide could be detected by XRD,and the theoretical detection limit was 0.72%.For TG-DSC method,1%lanthanum carbonate octahydrate in lanthanum hydroxide could be detected,and the theoretical detection limit was 2%.The testing results by XRD method were better than those obtained by TG-DSC method.