火焰原子吸收光谱法测定镧热还原稀土金属及熔盐电解稀土金属中锂含量  

Determination of Lithium in Rare Earth Metal Produced with Lanthanum Thermal Reduction or Molten Salt Electrolysis by Flame Atomic Absorption Spectrometry

作　　者：包香春[1,2] 张秀艳[1,2] 李建亭[1,2] 李净岩 BAO Xiang-chun;ZHANG Xiu-yan;LI Jian-ting;LI Jing-yan(State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China;National Engineering Research Centre of Rare Earth Metallurgy and Function Materials,Baotou 014030,China)

机构地区：[1]包头稀土研究院白云鄂博稀土资源研究与综合利用国家重点实验室,内蒙古包头014030 [2]稀土冶金及功能材料国家工程研究中心,内蒙古包头014030

出　　处：《稀土》2020年第5期93-98,共6页Chinese Rare Earths

摘　　要：采用硝酸低温溶解试样,选择Li 670.8 nm作为分析谱线,建立了火焰原子吸收光谱法(FAAS)测定镧热还原稀土金属及熔盐电解稀土金属中锂含量的方法。确定了FAAS的最佳工作条件为空气流量固定在15 L/min时乙炔气最佳流量为1.75 L/min,燃烧器高度为7 mm。实验表明,盐酸浓度对测定结果影响很大,测定时必须严格控制盐酸浓度,而硝酸浓度对测定结果无明显影响,实验选用5 mL硝酸溶解试样,5%(体积分数)的硝酸为测定介质;共存元素对测定的干扰可忽略。锂的浓度与吸光度呈良好的线性关系,线性回归方程为Y=0.1944X+0.009336,相关系数r=0.9997,方法检出限为0.0066μg/mL。采用工作曲线法和标准加入法测定实际试样,选择操作较简单且能满足检测要求的工作曲线法。采用实验方法测定稀土金属中锂含量,其相对标准偏差(RSD,n=11)<5%,加标回收率在91.0%~102.7%之间。The method of flame atomic absorption spectrometry(FAAS)was used to determine the content of lithium in rare earth metal produced with lanthanum thermal reduction or molten salt electrolysis,by using Li670.8 nm as the analytical line.The optimum working conditions of FAAS were determined as the optimal flow rate of acetylene gas at 1.75 L/min when the air flow rate was 15 L/min and the burner height of 7 mm.The results showed that the concentration of hydrochloric acid had a great influence on the determination results,and the concentration of hydrochloric acid had to be strictly controlled.The nitric acid concentration had no significant effect on the determination results,so 5 mL nitric acid was selected to dissolve sample and 5%(volume fraction)of nitric acid was used as the determination medium.The interference of coexistence elements on the measurement could be ignored.The linear regression equation was Y=0.1944 X+0.009336,the correlation coefficient of calibration curve for lithium was not less than 0.9997,and the detection limit was 0.0066μg/mL.The working curve method and standard addition method were used to determine the actual sample,and the working curve method was selected which was relatively simple and could meet the testing requirements.The relative standard deviation(RSD,n=11)<5%and the recoveries were between 91.0%and 102.7%.

关 键 词：镧热还原 熔盐电解 锂 火焰原子吸收光谱法(FAAS) 

分 类 号：TG115.33[金属学及工艺—物理冶金]