Development of high-purity iridium matrixes for spectral analysis

High-purity iridium matrixes used in spectral analysis were developed to meet the request of the new national standards to iridium standard samples.The technological flow of high-purity Ir matrixes for spectral analysis was determined through experimental study.The process was comprised of removing base metal cations by P₂₀₄ solvent extraction,removing precious metal impurities in the form of complex anions by N₂₃₅ solvent extraction,removing Rh and other metal impurities by H₂ reducing in solution,removing trace base metal cations by 732^# exchange resin,precipitating Ir by NH₄Cl,reducing Ir by H₂,and removing Si by HF.The grade of high-purity Ir matrixes is up to 99.999%.In the course of experimental study,the direct recovery rate and the total recovery rate of Ir are 61.99% and 95.26%,respectively.