Determination Of Uranium Content In Zirconium-rich Associated Radioactive Ore Samples By Ultraviolet Pulse Fluorimetry

On the basis of previous research work,the software of ultraviolet pulse light–induced fluorescence micro uranium analyzer(MUA)was upgraded,and various anions and cations and organic matter interference were tested.Based on this,a method was developed to determine the content of uranium in Naturally Occuring Radioactive Material(NORM)ore samples associated high zirconium content.MUA method for the determination of uranium in high content of zirconium ore samples has the characteristics of good accuracy,high precision,strong anti-interference ability,good adaptability,and comparable with inductively coupled plasma mass spectrometry for uranium measurement.The main results are as follows:1)The software for MUA was upgraded.The data acquisition and processing software of the instrument has been developed using Labview2010 version development environment,and the efficiency of the instrument is improved.2)The results show that the pH value is one of the key factors affecting the fluorescence intensity.In the pH 6.85~9.10 range,the fluorescence intensity is stable.The interference of 44 kinds of cations,anions and organic matter has been investigated.The fluorescence intensities for As,Sn,Cr,Sb,Tl,Rh,Mn,Ag,and ethanol are decreased,and has no obvious influence when the concentration of Zr in solution is bellow 200μg/mL,decreased gradually when the concentration of Zr between 200μg/mL and 500μg/mL.By adopting standard addition method,the interference of components mentioned above can be overcome.3)Samples with high zirconium can be digested completely using sodium peroxide fusion followed decomposition by nitric acid and measurement with MUA.The detection limit 0.05μg/g,range of determination 0.15μg/g~4500μg/g,precision2.1%~7.7% for U 40μg/g~735μg/g,and accuracy 5.2% for U 288μg/g were achieved by the standard addition method.The method is superior in performance and is alsoinnovatice.4)ICP-MS measurements were compared and the results were consistent.As far as uranium is concerned,the MUA is very important as a supplement method to ICP-MS due to its adoptability of alkali fusion,low cost and high efficiency.