Optimizing the Extraction of Rare Earth Elements from Char by Combining Physical Beneficiation and Acid Leaching in the Context of Techno-Economic Analysis

The sustainable recovery of rare earth elements (REE-Y) from electronic waste is critical for clean-energy technologies. Yet, the commercial viability of recovering REE-Y from shredder residue char (SR-char) remains unexplored. This study assesses a hybrid physical–chemical process utilizing SR-char, which integrates particle size classification and dry magnetic separation with optimized hydrochloric acid leaching. A first-order gross-profit screening model was developed to evaluate direct reagent economics of the proposed process, calculating revenue minus acid and neutralization costs, while excluding capital expenditures, labor, utilities, and separation losses. Results indicate that magnetic separation at 8000 G pre-concentrated REE-Y to >1800 g/t, and subsequent hydrochloric acid leaching yielded extractions of ~2000 g/t in the 500–1000 µm fraction. However, the profit model highlighted that maximized extraction in the presence of high concentrations of metals like Fe, Ca, and Al could lead to financial losses due to excessive reagent and neutralization expenses. Thus, physical pre-concentration to minimize non-target metal content is essential for economic viability. This targeted approach shifts optimization from metallurgical yield to economic feasibility, offering a transferable framework for evaluating other complex secondary REE-Y resources where impurity-driven costs significantly impact process economics.