Determination of vanadium in vanadium ore by inductively coupled plasma atomic emission spectrometry with microwave digestion

The rapid and accurate determination of the vanadium content in vanadium ore is of great significance for the development and geological exploration of vanadium deposit resources. In this study, a method for the determination of vanadium (expressed as V₂O₅) in vanadium ore by inductively coupled plasma atomic emission spectrometry (ICP-AES) with microwave digestion was established. To address the characteristics of vanadium titano-magnetite (difficult to decompose) and vanadium-bearing stone coal (containing organic matter), the sample was digested using a hydrofluoric acid-nitric acid mixture in a closed-vessel microwave system. After digestion at 200 ℃ for 30 min and subsequent evaporation to near dryness at 170 ℃, the residue was leached with 5%(volume fraction) aqua regia. This procedure effectively avoided corrosion from hydrofluoric acid and interference from extraneous impurities. Based on spectral line comparison, V 292.402 nm was selected as the optimal analytical line for vanadium. The calibration curve showed good linearity for vanadium in the mass concentration range of 100-10 000 ng/mL, with a correlation coefficient (r) greater than 0.999. The limit of detection of method was 26 μg/g. The proposed method was applied to the analysis of certified reference materials (CRMs) for vanadium-titanium magnetite (GBW(E)070126-GBW(E)070130). The obtained results of V₂O₅ were in good agreement with the certified values, with relative errors (RE) ranging from -1.68% to 0.80% and relative standard deviations (RSD,n=6) between 1.7% and 3.6%, meeting the requirements of DZ/T 0130.3-2006. Method comparison experiments demonstrated that the results of this method were in better agreement with the certified values than those obtained by alkali fusion-ICP-AES. The verification results confirm that the proposed method possesses high accuracy and good repeatability, making it suitable for high-throughput and efficient detection of vanadium in vanadium ores.