共沉淀分离-电感耦合等离子体原子发射光谱法测定含难熔金属岩石中12种稀土元素

Determination of twelve rare earth elements in rock containing refractory metals by inductively coupled plasma atomic emission spectrometry with coprecipitation separation

准确测定稀土元素含量,对是否开采含难熔金属岩石的矿山中稀土元素具有重要指导意义。实验采用Na2O2在750℃马弗炉中熔融样品,熔融体冷却后用盐酸(1+4)转入烧杯中,往溶液中加入氨水,以样品做载体,共沉淀分离除去钠盐及能与氨水形成络氨离子的金属元素,沉淀物用稀氨水洗涤、热稀盐酸溶解,以电感耦合等离子体原子发射光谱法(ICP-AES)测定试液中La、Ce、Sm、Eu、Gd、Tb、Ho、Er、Dy、Tm、Yb、Y,建立了含难熔金属岩石中12种稀土元素的测定方法。各元素校准曲线的线性范围为0.10~25μg/mL,方法的检出限0.20~1.0μg/g。按照实验方法测定含难熔金属岩石物料中La、Ce、Sm、Eu、Gd、Tb、Ho、Er、Dy、Tm、Yb、Y等12种稀土元素,结果的相对标准偏差(RSD,n=9)为3.2%~6.2%,加标回收率为90%~110%。实验方法可用于含难溶金属岩石中稀土元素含量为0.001%~0.50%(质量分数)的测定。

The accurate determination of rare earth elements was of great significance for the mining of rare earth elements in mine of rock containing refectory metals.The sample was fused with sodium peroxide in muffle furnace at 750℃.After cooling,the melt was transferred into a beaker with hydrochloric acid(1+4)followed by adding ammonia water into solution.The sample was used as carrier to remove sodium salts and metal ions which could react with ammonia to form ammonia complexation ions by coprecipitation separation.The precipitates were washed with diluted ammonia water and then dissolved with hot diluted hydrochloric acid.La,Ce,Sm,Eu,Gd,Tb,Ho,Er,Dy,Tm,Yb and Y in the test solution were determined by inductively coupled plasma atomic emission spectrometry(ICP-AES).Consequently,a determination method of the above twelve rare earth elements in rock containing refectory metals was established.The linear ranges of calibration curves of these elements were between 0.10μg/mL and 25μg/mL.The detection limits of method were between 0.20μg/g and 1.0μg/g.The contents of twelve rare earth elements(including La,Ce,Sm,Eu,Gd,Tb,Ho,Er,Dy,Tm,Yb and Y)in rock samples containing refectory metals were determined according to the experimental method.The relative standard deviations(RSD,n=9)of determination results were between 3.2%and 6.2%,and the recoveries were between 90%and110%.The proposed method was applicable for the determination of rare earth elements(the mass fractions were in range of 0.001%-0.50%)in rock containing refectory metals.