Determination of Impurities in Vanadyl Sulfate Used for Vanadium Battery by ICP-OES

The method for simultaneously determining the contents of 8 key impurities in the vanadyl sulfate solid used for vanadium battery by inductively coupled plasma atomic emission spectrometry(ICP-OES) was established respectively with the detection range of 0.001%~0.100% for Fe,Cr,Ni and 0.005%~0.100% for K,Na,Ca,Si,Al.The influences of the matrix effects,spectral interferences and continuous background superposition on the measurement of impurities in the samples with coexisting high concentration of vanadium ion and sulfate radical have been studied.It is shown that the sulfate radical in the samples does not affect the measurement,and the matrix effects or continuous background superposition generated by high concentration of vanadium ion,have a negative interference on the content determination for K and Na while a positive interference on the measurement of other impurities such as arsenic(As),cobalt(Co),iron(Fe) and nickel(Ni),etc.Meanwhile,the interference caused by high vanadium matrix was eliminated by combinative method of matrix matching and synchronous background correction.The interferences of vanadium matrix on the impurities spectra were also classified and summarized by spectral interference tests,and the analytical spectral lines,background correction regions and working parameters of the spectrometer were optimized.The technical performance indexes of this analysis method are-0.000 3%~0.000 3% of background equivalent concentration,0.000 1%~0.000 3% of element detection limit,RSD <10% with 0.001%~0.007% of element content,and 91.0%~110.0% of recovery rate.