四酸消解-电感耦合等离子体质谱法测定铝土矿中18种元素的含量

Determination of 18 Elements in Bauxite by Inductively Coupled Plasma Mass Spectrometry with Four-Acid Digestion

提出了四酸(盐酸+硝酸+硫酸+氢氟酸)消解-电感耦合等离子体质谱法(ICP-MS)同时测定铝土矿中锂、钪、铌和15种稀土元素(镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、钇)含量的方法。取0.100 0 g粉末样品置于50 mL聚四氟乙烯坩埚中,加少量水润湿,加入5.0 mL盐酸,置于100℃控温电热板上加热30 min,冷却。加入1.0 mL 50%(体积分数)硫酸溶液、5.0 mL硝酸、5.0 mL氢氟酸,于100℃加热3 h,静置过夜后,于150℃加热,待消解液体积蒸发至1~2 mL时,升温至220℃,待浓烟冒尽,冷却。加入5 mL体积比1∶3的硝酸-盐酸混合溶液和5 mL水,于100℃加热以溶解盐类并蒸干溶液,重复操作待溶液澄清后冷却,用1 g·L^(-1)酒石酸溶液定容至100 mL,静置过夜。取10 mL上清液,用0.3 mol·L^(-1)硝酸溶液稀释至50 mL,与10μg·L^(-1) ^(103)Rh内标溶液在线混匀后,采用ICP-MS测定。结果表明:各元素的质量浓度在一定范围内和对应的信号强度与内标信号强度比呈线性关系,检出限(3s)为0.006~0.040 mg·kg^(-1);平行测定铝土矿样品1^(#)、2^(#)、3^(#)各11次,测定值的相对标准偏差(n=11)小于6.0%;对空白试剂溶液进行3个浓度水平的加标回收试验,回收率为92.0%~108%。

A method for simultaneous determination of lithium,scandium,niobium,and 15 rare earth elements (lanthanum,cerium,praseodymium,neodymium,samarium,europium,gadolinium,terbium,dysprosium,holmium,erbium,thulium,ytterbium,lutetium,and yttrium) in bauxite by inductively coupled plasma mass spectrometry (ICP-MS) with four-acid digestion was proposed.0.100 0 g of the powder sample was taken,placed into a 50 mL-polytetrafluoroethylene crucible and wetted with a small amount of water,and 5.0 mL of hydrochloric acid was added.The mixture was heated at 100℃for 30 min on a controlled electric heating plate and cooled.1.0 mL of 50%(volume fraction) sulfuric acid solution,5.0 mL of nitric acid,and 5.0 mL of hydrofluoric acid were added.The mixture was heated at 100℃for 3 h.After settling overnight,the solution was heated at 150℃until the volume of the digestion solution was evaporated to 1-2 mL,and then the temperature was raised to 220℃until the thick smoke was completely emitted.After cooling,5 mL of the mixed solution of nitric acid and hydrochloric acid at a volume ratio of1∶3 and 5 mL of water were added,and then the mixture was heated at 100℃to disslove the salts and evaporate the solution to dryness.The process was repeated until the solution was clear,and it was cooled and made its volume up to 100 mL with 1 g·L^(-1)tartaric acid solution.After settling overnight,10 mL of the supernatant was taken,diluted to 50 mL with 0.3 mol·L^(-1) nitric acid solution,mixd well online with 10μg·L^(-1) ^(103)Rh internal standard solution,and determined by ICP-MS.As shown by the results,linear relationships between the ratios of the corresponding signal intensity to the internal standard signal intensity and mass concentrations of elements were kept in definite ranges,with detection limits (3s) in the range of 0.006-0.040 mg·kg^(-1).The bauxite samples (1~#,2~#,and 3~#) were determined in parallel 11 times,respectively,with RSDs (n=11) of the determined values less than 6.0%.Test for recovery was made on blank reagent solution by standard addition method at 3 concentration levels,giving results in the range of 92.0%-108%.