A wavelength-dispersive X-ray fluorescence spectrometry method for determining elemental content in coal tar pitch

While X-ray fluorescence spectrometry (XRF) is extensively applied for elemental analysis of liquids and solids, conventional wavelength-dispersive XRF (WD-XRF) encounters significant limitations when analyzing viscoelastic substances due to their adhesive properties and thermal instability. Bituminous materials represent a characteristic example within this category. To overcome these constraints, the present study introduces a sample preparation protocol. The method involves vibratory grinding of a proportionally blended mixture of the sample with additives-such as boric acid or lithium borates-in a tungsten carbide bowl, followed by pressing the homogenized powder into pellets for WD-XRF measurement. Additives fulfill dual roles: reducing material viscosity during grinding to ensure processing consistency, while suppressing thermal-induced flow during analysis to prevent pellet softening and maintain operational safety. This study systematically optimized key preparation parameters for pressed pellet preparation, including sample-to-additive ratios, grinding time, softening resistance test and infinite thickness. The WD-XRF analytical results exhibited strong concordance with inductively coupled plasma optical emission spectrometry (ICP-OES) and combustion-infrared carbon/sulfur (CS-IR) analysis. This study developed a novel WD-XRF method for safe and efficient analysis of coal tar pitch, extending the safe application range of WD-XRF technology. The proposed approach demonstrates potential for broader applications in sectors such as plastics, petrochemicals, construction materials and food industries.