APPLICATIONS OF HIGH-PERFORMANCE ION CHROMATOGRAPHY IN THE MINERAL PROCESSING-INDUSTRY

A reversed-phase column, coated with a permanently sorbed ion exchanger ("permanent coating" ion-interaction chromatography), was used for the separation of anions in ground water samples from a hydrometallurgical processing plant. Optimization of the capacity of the anion exchanger and wide linear range calibration curves obtained with these columns permitted the direct determination of Cl-, NO2-, NO3-, and SO42- in the presence of large amounts of ammonium and metal ions. Dynamic ion exchange ("dynamic coating" ion-interaction chromatography) was investigated for the separation of rare earths in samples from an aluminum processing operation. Data is presented to illustrate that with appropriate adjustment of pH of the eluent it is possible to optimize conditions to resolve rare earth metals from interfering metal ions. The selective sorption of Th(IV) and U(VI) on to reversed phases as their alpha-hydroxyisobutyric complexes, formed in situ in the eluent, was used for the analysis of samples from bacterial leaching of uranium ores. By minimizing the baseline noise of the post-column reaction the detection limit for Th(IV) is 5-mu-g/l and for U(VI) is 15-mu-g/l (3 x baseline noise) for a 100-mu-l sample injection.