Uptake mechanism and speciation of Yttrium in phosphogypsum: Insights into waste valorization and resource recovery

Phosphogypsum (PG), a byproduct of phosphate fertilizer production, contains rare earth elements (REEs), making it a potential resource for REE recovery. Understanding yttrium (Y) speciation in PG is crucial for optimizing extraction strategies. This study combines µ-XRF, HR-XANES, and µ-EXAFS to analyze Y distribution, partitioning, and coordination in PG samples subjected to controlled pH and temperature treatments. These conditions simulate both natural leaching and industrial processing, providing insight into Y retention mechanisms. Spectral analysis using linear combination fitting, shell-fitting, and wavelet transforms will identify Y binding modes and structural environments. By elucidating Y behavior in PG, this study advances REE recovery strategies and promotes sustainable industrial waste valorization, contributing to the circular economy.