Extraction of Nb, Ta, Zr and Hf from tin slags originating from cassiterite beneficiation

• Introduces a fluoride-free process for extracting Nb, Ta, Zr, and Hf from tin slags using sulfuric acid thermal treatment and leaching. • Thermodynamic simulations predict optimal conditions for sulfate complex formation, enhancing metal recovery and reducing energy consumption. • The proposed pyro-hydrometallurgical route avoids hazardous hydrofluoric acid, mitigating environmental impacts. • The generated PLS is enriched with target metals, suitable for downstream purification via solvent extraction.