Leaching of Critical Rare-Earth Elements from Industrial Phosphogypsum from the Wizów Deposit

Abstract

Phosphogypsum (PG) is a by-product of phosphate fertilizer production. It consists mainly of calcium sulfate dihydrate and retains impurities such as toxic trace elements and naturally occurring radionuclides. Approximately 200 million tons of PG are produced annually globally, which raises environmental contamination concerns due to large PG deposits. However, PG waste also contains rare-earth elements (REEs), presenting an opportunity for resource recovery. REEs are crucial economic raw materials listed on the European Union (EU) Critical Raw Materials 2020 list and are extensively used in the industry, increasing global demand. This study focuses on the hydrometallurgical recovery of critical REEs from PG waste sourced from the former chemical plant in Wizów, Poland. Leaching experiments were conducted with various solvents to evaluate REE extraction efficiency. Elemental analysis was performed using inductively coupled plasma–mass spectrometry (ICP-MS), with total REE concentrations (ΣREEs) ranging from 0.04 to 1.57% w/w. The study demonstrates the potential of PG waste as a secondary REE resource, which offers benefits for both critical material recovery and waste reduction. It supports sustainable hydrometallurgical processing of PG for environmental management and raw material security in the EU.