Determination of vanadium and tungsten in waste vanadium-titanium-based denitration catalyst by inductively coupled plasma atomic emission spectrometry after extraction separation
The accurate determination of vanadium and tungsten contents in waste vanadium-titanium-based denitration catalyst(V2 O5-WO3/TiO2)has important significance for the recycle of related metal re-sources.In order to reduce the influence of matrix effect,the waste vanadium-titanium-based denitration catalyst was digested with sulfuric acid at high temperature.Then vanadium and tungsten were extracted with extractant(20％N1923+2％sec-octyl alcohol+78％sulfonated kerosene,V/V)for separation.Fi-nally,the contents of vanadium and tungsten were determined by inductively coupled plasma atomic emis-sion spectrometry(ICP-AES).The pretreatment conditions of sample were obtained based on the single factor experiment results:the dosage ratio of catalyst to 80％sulfuric acid(m/m)was 1∶40(solid-liquid ratio,g/mL);the concentration of N1923 was 20％(volume fraction),and the volume ratio of organic phase to aqueous phase(O/A)was 2∶1 in the extraction process;during back extraction,the concentra-tion of sodium hydroxide solution was 1 mol/L,and the ratio of O/A was 1∶2.The results showed that the mass concentration of vanadium and tungsten in range of 1.0-10.0 μg/mL and 2.0-20.0 μg/mL was linear to the corresponding emission intensity,respectively.The correlation coefficient was 0.999 5 and 0.999 6,and the limit of detection was 0.002％and 0.003％(mass fraction),respectively.The contents of vanadium and tungsten in three waste vanadium-titanium-based denitration catalyst samples were deter-mined according to the experimental method,and the relative standard deviations(RSD,n=11)of meas-urement results were less than 4.0％.The found results were consistent with those obtained by X-ray flu-orescence spectrometry in GB/T 31590-2015.
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