engleski

Spectrometric Techniques (SEM, HR AES, XPS) Applied in the Metallurgical Waste Characterisation

Metallurgical waste management, including the choice of its final disposal, has to be preceded by its characterisation. During this process, a series of tests of physical and chemical properties of the waste and of its potential interaction with the environment is conducted. The waste material analysis applies the standard methods and techniques to determine the drying loss, specific area, sample density, water solubility, granular-metric and chemical composition. It also applies various spectrometric techniques to examine the physical and chemical characteristics. Scanning electron microscopy (SEM) is often applied to test morphological and qualitative chemical composition of waste, whereas high-resolution Auger electron spectroscopy (HR AES) and X-ray Photoelectron Spectroscopy (XPS) are applied to determine the possible structure forms of the compounds in the sample base. The paper displays the application of these spectrometric techniques in the case the characterisation of electric arc furnace (EAF) dust , which is the major representative of the hazardous metallurgical waste group. The obtained results of the grain size test imply that the diameters of particles and their clusters range from ~ 1 m to ~ 200 m. The shape of EAF dust particles is mostly spherical, and very few are angular. The recorded agglomerates are mostly cluster-shaped, whereas some have wrinkled spherical surface. The results of the qualitative scanning electron microscopy of EAF dust particles imply the presence of Fe, Zn, Pb, Mn, Cu, Al, Ca, Mg, K, S, P, C, O, and Cl. Furthermore, the analysis of microscopic images and the examination of the distribution of these elements across the image surface has shown that the dust samples basically contain the compounds of the Fe-O, Zn-O, Pb-O, Ca-O, Si-O, Mg-O, and Pb-S-O type. The recorded HR AES spectra have also displayed the presence of Fe, Zn, Pb, Mo, Al, Ca, Mg, Si, S and O as well as their different quantitative distribution in the analysed particles. The analysis of XPS spectra has confirmed the results of qualitative HR AES chemical analysis. By means of the measured bonding energy of Zn, Pb, and Ca the structural shapes of these elements were determined i.e. it was proven that zinc was tied up as ZnO, lead as PbO, PbSO3 and/or PbSO4, and calcium as CaO and CaCO3 . The obtained results can provide a basis for the interpretation of potential reaction between this type of metallurgical waste and the environment and hence for the choice of the optimal management solution through the application in the plant’ s own technological process (where this waste is actually generated), usage in other industrial branches, or final disposal of properly pre-treated waste at registered land fills.

metallurgical waste; spectrometric techniques; EAFdust; characterization

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