Quantitative Analysis of Uranyl Complexes Based on Quantitative Raman Spectroscopy

ABSTRACT The concentration of uranium in uranium‐bearing pregnant solution is a key parameter reflecting the efficiency of in situ leaching for uranium mining and is usually at the mg/L level. Current methods face difficulties in obtaining the species and concentration of uranyl complexes in the pregnant solution at the mg/L level quickly and nondestructively. In this work, an analytical method for species identification and concentration detection at the mg/L level of uranyl complexes was proposed based on quantitative Raman spectroscopy. Using the pregnant solution from the CO 2 + O 2 in situ leaching as the standard sample, the Raman quantitative relationships of uranyl complex concentrations in the pregnant solution were established. The results show the following: Based on Raman spectroscopy, uranyl dicarbonate [UO 2 (CO 3 ) 2 2− ] and uranyl tricarbonate [UO 2 (CO 3 ) 3 4− ] can be quickly identified. Using water as the internal standard, the concentrations of both UO 2 (CO 3 ) 2 2− and UO 2 (CO 3 ) 3 4− are in the linear relationship with the peak height ratio of the Raman peaks, which can be used to detect the concentration of uranyl complexes in the low‐concentration pregnant solution.