A Business Model Framework for Scaling Bioleaching Technology: From Laboratory to Semi-Industrial Applications for CRM Recovery from E-Waste PCBs

Innovative technological solutions for waste electrical and electronic equipment are critical for circular and sustainable economy. E-waste, generating 57.4 million tonnes annually, includes around 6 million tonnes of printed circuit boards (PCBs), which are rich in critical raw materials (CRMs) such as copper, nickel, zinc, cobalt, lead, and chromium. Despite this potential, less than 40% of e-waste is recycled in the EU. Bioleaching, employing acidophilic autotrophic bacteria to extract metals at ambient temperature, provides a sustainable alternative to pyrometallurgical and hydrometallurgical methods, yet industrial-scale deployment remains challenging. This study presents a complete bioleaching value chain—from mechanical pre-treatment and froth flotation to stirred-tank bioleaching and solvent extraction—demonstrated at three reactor scales (2 L, 20 L, and 100 L) over 30 days at 30 °C. Metal recovery was quantified by X-ray fluorescence. At 2 L, a mixed Acidithiobacillus ferrooxidans/A. thiooxidans inoculum recovered 47.3% Cu, 93.4% Ni, and 96.3% Cr. At 20 L, A. thiooxidans achieved 64.3% Cu and 90.3% Ni, and at 100 L, recoveries reached 53.5% Cu and 92.0% Ni. Coupled with an estimated 64% reduction in CO₂ emissions, these results confirm that bioleaching is a technically viable and commercially deployable method for CRM recovery from e-waste.