Technical Articles From University of L'Aquila

Smart Determination of Gold Content in PCBs of Waste Mobile Phones by Coupling of XRF and AAS Techniques

May 28, 2024 | Nicolò Maria Ippolito , Gianmaria Belardi , Valentina Innocenzi , Franco Medici , Loris Pietrelli and Luigi Piga

: Quantitative determination of most economic valuable metals in waste is the first fundamental operation of evaluating the feasibility of recycling processes. Field-portable X-ray fluorescence
spectrometers (FPXRFs) represent a more practical, efficient, and economic tool in determining the
elemental composition of samples with respect to conventional analytical techniques, such as atomic
absorption spectrometry (AAS) and inductively coupled plasma emission spectrometry (ICP). In
this paper, quick and smart determination of gold content in printed circuit boards (PCBs) of waste
mobile phones was studied. The aim of the research was to combine the practicality of FPXRFs
with the reliability of quantitative spectrometry analysis and evaluate the error between the two
techniques. Several samples (33) of PCBs were ground to a size below 0.5 mm, and then, the powders
were analyzed by FPXRFs at different acquisition times with five replications for each sample. The
same analyzed samples then underwent chemical attack to determine the quantitative gold content
by AAS. The obtained results were associated with FPXRFs response with the purpose of realizing
a calibration curve (100–1000 mg/kg Au). The curve was validated for accuracy and precision by
other PCBs waste samples; the control samples were added as standards to obtain a more reliable calibration curve. The curve was evaluated with RPD classification, regression linear, and Bolt–Altman
analysis.