The use of computational thermodynamic for yttrium recovery from rare earth elements-bearing residue

The rare earth elements are considered critical metals, due to the risk of supply interruption. The recycling of waste electrical and electronic equipment can be an alternative to supply the rare earth market. Several processes have been developed, and by aqueous media is the most prominent, which makes possible the extraction and separation of elements even in low concentration (traces). As an example of thermal processing, the use of thermodynamic simulations might benefit the metal extraction in hydrometallurgical processing. For this reason, the goal of this work is to evaluate the use of FactSage 7.2 software for the leaching of fluorescent lamp powders by sulfuric acid. The effect of concentration and temperature was evaluated. Results comprise that the thermodynamic software well-predicted the solid phase formed in all residues of leaching experiments – gypsum was predicted by the software and identified in XRD analyses. It demonstrates that FactSage software can be explored for metals extraction in aqueous media, being important for trace-elements extraction. Yttrium extraction reaches up to 95% at 45 °C using H₂SO₄ 2 mol/L.