铁及稀土元素在DOWEX 1-X8阴离子交换树脂上分配系数的测定及其应用于原子发射光谱法测定钢中稀土元素含量
Detemination of Distribution Coefficients of Iron and Rare Earth Elements on DOWEX 1-X8 Anion Exchange Resin and Its Application to ICP-AES Determination of Rare Earth Elements in Steel
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摘要: 对铁和稀土元素在DOWEX 1-X8阴离子交换树脂上于不同浓度的盐酸和硝酸介质中的分配系数(Kd)进行了研究,试验结果表明:在6~9 mol·L-1盐酸介质中Fe3+的Kd>103,即强吸附于DOWEX 1-X8阴离子交换树脂,而稀土元素在DOWEX 1-X8阴离子交换树脂的Kd≤10,即不吸附于树脂;而在浓度低于2 mol·L-1的硝酸介质中,Fe3+的Kd<6.4,即不吸附于树脂上,故选用1.6 mol·L-1硝酸溶液将吸附于柱上的Fe3+洗脱下来.在此基础上提出了一种阴离子交换树脂分离电感耦合等离子体原子发射光谱法测定洁净钢中微量稀土元素含量的方法.该方法用于测定产于日本及韩国的洁净钢样品,测得回收率在87.7%~118.3%之间,相对标准偏差(n=6)小于23%.Abstract: The distribution coefficients (Kd) of Fe3+ ion and ions of rare earth elements on DOWEX 1-X8 anion exchange resin in hydrochloric acid or nitric acid solutions of different acidites were studied.It was found that in 6-9 mol·L-1 hydrochloric acid,the Kd of Fe3+ was more than 103,while the Kd of rare earth elements were equal to or less than 10,hence,Fe3+ was adsorbed strongly on the resin,and ions of rare earth elements were not.The Kd of Fe3+ was less than 6.4 in nitric acid solution of concentration less than 2 mol·L-1,so Fe3+ was eluted from resin with 1.6 mol·L-1 nitric acid as eluent.Based on these facts,a method for separation of rare earth elements from matrix of iron was proposed and applied to the ICP-AES determination of rare earth elements in clean steels.Samples of clean steel produced in Japan and Korea were analyzed by the proposed method,giving values of recovery in the range of 87.7%-118.3%,and values of RSD′s (n=6) less than 23%.
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