Authors: Inmaculada de la Calle, M. Quade, T. Krugmann, U.E.A. Fittschen
Journal: X-ray Spectrometry, 43: 34-46, 12/2014
Total reflection X-ray fluorescence spectrometry (TXRF) was used to determine residual metal content in metallurgical slag after sulfuric acid extraction. A slag sample provided by a copper smelter industry and submitted to a recycling process with the aim of extracting valuable metals was analyzed. Slurry sampling was evaluated as a simple sample preparation procedure for the determination of major (Si, Fe, K, Ca) and trace elements (Ti, Ni, Cu, Zn, As, Pb, Sr, Rb, Mn) in two certified reference materials (lake and river sediments) to evaluate the accuracy of the procedure. Precision was evaluated as relative standard deviation (%) of three replicates, being usually lower than 10%. Detection limits were in the range of 1.1–1079 µg g−1. Additionally, it was evaluated to use Si – a major component of the slag – as intrinsic reference to determine residual elements in the slag residues. A two-element internal standard (Ga + P) was employed to determine all the elements. Ga was used as internal standard for the determination of elements from K to Pb, and P was required for the quantification of Si. The optimal procedure of slurry sampling was applied for the analysis of the original metallurgical slag and the solid residues. It was found that As and Pb are accumulated in the slag, whereas Cu, Zn, and Fe are extracted to a percentage >90% from the slag. This was confirmed by analysis of the sulfuric acid extracts of the metallurgical slag.