Determination of Nb and Ta in Ores and Metallurgical Samples by Inductively Coupled Plasma-Atomic Emission Spectrometry with Ethanol as a Sensitizer

Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) has been widely used in the determination of Nb and Ta, but its low sensitivity and high detection limits cannot meet the analysis requirement of low content Nb and Ta in ores and metallurgical samples. The sensitizing effect of many organic reagents was optimized in the ICP-AES determination. The results show that ethanol is the best sensitizer for determination of Nb and Ta after the samples were decomposed by open acid-solution with HF-HNO₃-H₂SO₄ mixture. When the concentration of ethanol reaches 6%, the sensitivities of Nb (292.781 nm) and Ta (240.063 nm) have increases of 180.5% and 265.5%, respectively. Moreover, the detection limits of Nb and Ta were reduced from 5.85 to 3.22 μg/g and from 10.65 to 5.03 μg/g, respectively. The recoveries of Nb₂O₅ and Ta₂O₅ were 97.7%-101.9% and 96.8%-97.2%, respectively. The precision of this method was less than 6%. The method is suitable for the simultaneous determination of low and high contents of Nb and Ta, and is particularly suitable for determining Nb and Ta in ore concentrates, medium ores and the tailings of metallurgical samples from the same batch, which overcomes the bad agreement of recovery between ICP-AES and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS).