Determination of Li, Be, Nb, Ta, Rb, Cs in Rare Polymetallic Ores by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) with Microwave Digestion.

The six elements of lithium, beryllium, niobium, tantalum, rubidium and cesium in rare polymetallic ores often coexist together. Beryllium minerals are mostly difficult to be completely dissolved by acid, while niobium and tantalum are easy to be hydrolyzed. The accurate determination of these elements requires a variety of methods and complicated analysis process. In this paper, a method for simultaneous determination of lithium, beryllium, niobium, tantalum, rubidium and cesium in rare polymetallic ores by microwave digestion and inductively coupled plasma mass spectrometry (ICP-MS) was established by investigating the holding time and the amount of extraction solution after microwave digestion. The results showed that the samples could be completely dissolved by holding for 30 min, and completely extracted by 10 mL of hydrofluoric acid (1 + 1) and 3 drops of hydrofluoric acid. The mass spectrum signals of each element showed a good linear relationship in the concentration range of 0--20 jug/mL, and the correlation coefficients (r) were above 0.999 9. The microwave digestion method and the electrothermal plate digestion method were used to determine the six rare polymetallic ores of national first-class standard substances respectively. The results showed that the determination of beryllium by the electrothermal plate digestion method was obviously low, and the determination results of each element by the microwave digestion method were within the error range of the recognized value. The detection limits were 3. 0--10. 0 jng/g, the test range was 0. 001%--4. 3%, and the relative standard deviation RSD (w=12) was 0. 32%--12. 5%. The quality parameters meet the requirements of geological and mineral experiments. [ABSTRACT FROM AUTHOR]