Ignacio Queralt

Determination of Water-Soluble Hexavalent Chromium in Clinker Samples by Wavelength-Dispersive X-ray Fluorescence Spectrometry after Concentration in Activated Layers

The determination of hexavalent chromium (Cr(VI)) in cement-related material extracts is frequently monitored in cement industries to comply with the European Directive (2003/53/EC) that limits the use of cements containing more than 2 mg kg−1 of water-soluble Cr(VI). In the present work, a rapid and simple method for the determination of water-soluble Cr(VI) in clinker samples has been developed. The analytical methodology is based on the combined use of a low cost Cr(VI) isolation procedure using activated layers followed by their analysis using wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. WDXRF instrumentation is a common tool used for determining the chemical composition of all materials involved in cement production and also for the quality control of the products produced in cement and concrete factories. Therefore, the presented methodology does not imply the use of additional instrumentation in cement-industries laboratories and can be used as a comparative method to the spectrophotometric reference (EN 196–10:2006). The analytical parameters evaluated (selectivity, limit of detection, linearity, and precision) prove to be suitable for the intended purpose, and the methodology has successfully been applied to determine water-soluble Cr(VI) in several clinker samples.

Investigation of the Composition of Historical and Modern Italian Papers by Energy Dispersive X-ray Fluorescence (EDXRF), X-ray Diffraction (XRD), and Scanning Electron Microscopy Energy Dispersive Spectrometry (SEM-EDS)

In this work, a study concerning the composition of Italian papers from the seventeenth to the twentieth centuries was carried out using energy dispersive X-ray fluorescence spectrometry (EDXRF), X-ray diffraction (XRD), and scanning electron microscopy coupled to energy dispersive spectrometry (SEM-EDS). The analyzed samples consisted of papers employed for drawing, writing, printing, and absorbance. Observations carried out by SEM magnified the typical paper morphology. EDXRF in combination with XRD and SEM-EDS allowed the determination of calcite, gypsum, kaolin, talc, magnesite, and dolomite, used as fillers in the production of the papers studied herein. The inks present in the handwritten and printed papers, investigated by SEM-EDS and μ-EDXRF, were synthetic, Fe based, and iron gall inks.

Analysis of lead content in automotive shredder residue (ASR)

Automotive shredder residue (ASR) is a very heterogeneous waste, which could have a very high metal content on finest fractions phi<6 mm produced by the shredding of end of live vehicles. The approval of Directive 2000/53/EC and its transposition to the European Union member states requires an analytical technique for in-situ checking of the content of some metals in ASR wastes. The objective of this study is the evaluation of total Pb content in the different fractions using a rapid measurement method to easily accomplish the current legislation. An experimental Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer with tri-axial geometry was used to analyse the ASR in order to test the feasibility of this analytical technique. Likewise, a correction of the intensities by the incoherent scattering (Compton) radiation was made to compensate the matrix effects. The results show that values in the smaller fractions are bigger (11,600 mg kg(-1) in the fraction <125 microm) than in the coarser fractions (4600 mg kg(-1) in the fraction between 2 and 6 mm) and that such type of instrumentation enables a fast measurement with a limit of detection of 1.1 mg kg(-1) for 1000 s measurement).

Fast Elemental Screening of Soil and Sediment Profiles using Small-Spot Energy-Dispersive X-ray Fluorescence: Application to Mining Sediments Geochemistry

Elemental analysis of different sediment cores originating from the Cartagena–La Union mining district in Spain was carried out by means of a programmable small-spot energy-dispersive X-ray fluorescence (EDXRF) spectrometer to study the distribution of heavy metals along soil profiles. Cores were obtained from upstream sediments of a mining creek, from the lowland sedimentation plain, and from a mining landfill dump (tailings pile). A programmable two-dimensional (2D) stage and a focal spot resolution of 600 μm allow us to obtain complete core mapping. Geochemical results were verified using a more powerful wavelength-dispersion X-ray fluorescence (WDXRF) technique. The data obtained was processed in order to study the statistical correlations within the elemental compositions. The results obtained allow us to observe the differential in-depth distribution of heavy metals among the sampled zones. Dump site cores exhibit a homogeneous distribution of heavy metals, whereas the alluvial plain core shows accumulation of heavy metals in the upper part. This approach can be useful for the fast screening of heavy metals in depositional environments around mining sites.