Analysis of Trace Elements by ICP-OES and XRF in Pulp and Paper Industry

Abstract

ICP-OES（Inductivity Coupled Plasma Optical Emission Spectrometer）is an analytical method characterized by the high sensitivity, wide dynamic range and multi-element analysis. ICP-OES is generally used to quantify trace metals in Pulp and Paper Industry samples. The pretreatment method for Fe, Ni, Cu, Zn, Cd and Pb in white liquor was studied by using a solid phase extraction column packed with polyamino-polycarboxylic acid type chelate resins. The recoveries of elements were affected by pH. All trace metals were found to be extracted with similar efficiency at pH 5.5, indicating that the optimum condition for extraction is pH 5.5. Major matrix elements, Na, Mg, K and Ca, in white liquor were not extracted below pH 7. The optimum concentration of nitric acid for elution after cleaning the column was determined to be 3 mol/L. The assay values agreed well with the pre-set values without the interference of the major elements. Moreover, high recoveries of the elements （100±1％） were achieved for the white liquor sample. A Cs inhibitor for ionization interference was effective to suppress the ionization interference of alkaline metal（K）in ICP-OES analysis. Assay values by ICP-OES using the inhibitor correlated well with those using IC（Ion Chromatography）. Also a simple analytical method with XRF（X-ray Fluorescence Analysis）using Ultra Carry Light filter provided the precise dilution factor easily. Furthermore, cross checking using XRF and ICP-OES improved the precision of the analysis.