Resource Accessibility of Rare Earths across Secondary Feedstocks. Byers et al.

Research Hypothesis and Context: Global supply chains for rare earth elements (REEs) remain concentrated in a small number of geographic sources, creating persistent supply risk. Reclaiming REEs from secondary feedstocks offers a path to supply chain resilience, but no prior study has systematically compared their technical and economic accessibility within a unified framework. This dataset was compiled to evaluate how REE accessibility, defined by elemental concentration, extraction efficiency, and breakeven processing cost, varies across secondary feedstock types. Data Description: This dataset contains 826 entries extracted from 305 peer-reviewed studies published between 2020 and 2025, compiled through a quantitative systematic literature review using Scopus and screened with Covidence. Each entry reports REE concentration (ppm) and extraction yield (%) for individual elements across 19 secondary feedstock categories, including e-waste (permanent magnets, batteries, lighting phosphors, catalytic converters, consumer electronics), industrial residues (LYSO crystals, metallurgical slag, phosphogypsum, bauxite residue, mine tailings, polishing powder, process tailings), combustion products (fly ash, bottom ash, incinerator ash), and wastewater sources (acid mine drainage, industrial process wastewater, environmental water). Additional fields include geographic source, extraction method (hydrometallurgy, pyrometallurgy, biometallurgy, electrometallurgy, physical), circular economy strategy classification, lifecycle stage of intervention, co-product and byproduct profiles, and economic notes where reported. Concentration data are normalized to elemental parts-per-million on a mass basis. Light REE (LREE), heavy REE (HREE), scandium, and total REE (TREE) sums are calculated per entry. Notable Findings: The data reveal an order-of-magnitude viability gap between high-grade anthropogenic feedstocks (e.g., permanent magnets, LYSO crystal waste, lighting phosphors) and dilute geogenic sources (e.g., fly ash, acid mine drainage). E-waste feedstocks consistently show the highest REE concentrations, highest extraction efficiencies, and widest economic margins. Users can filter by feedstock category, geographic origin, extraction method, or individual REE to conduct comparative analyses, identify reclamation targets, or benchmark new feedstock characterization data against the compiled literature.