The fourth newsletter of the FIREFLY project, launched shortly after its M24 meeting, reported promising results. The researchers achieved over 95 % tungsten (W) and more than 80 % vanadium (V) recovery from spent DeNOx catalysts through Mechanochemical Processing (MCP). Additionally, they nearly reached 100 % palladium (Pd) recovery from Pd-based catalysts used in lignin depolymerisation. In the Electro-driven Solvoleaching (ESLX) and Electro-driven Solvent Extraction (ESX) processes, they reported 85 % Pd recovery from spent catalysts and nearly 100 % stripping of Pd in non-aqueous solvent extraction. Discover all the results.