Rethinking antimony: Supply vulnerability, waste flows, and recovery pathways

Antimony (Sb) plays an important role in functional oxides: antimony trioxide (Sb₂O₃) is widely used in flame-retardant polymers and as a catalyst in PET, while oxidized Sb species and Sb-doped oxides enable electroceramic and oxide-electronic technologies. As a critical material with geographically concentrated supply, the United States is fully import-dependent and vulnerable to supply disruption. Here we map Sb mass flows in the U.S. economy, emphasizing the chemical forms that govern fate and recovery (Sb₂O₃ in plastics, Sb(III)/Sb(V) in aqueous phases, Sb⁰ in alloys). While lead-acid batteries achieve high recycling rates, large quantities of Sb₂O₃ in flame-retardant plastics and WEEE, and Sb embedded in discarded PET, enter landfilling and incineration, representing underutilized secondary reservoirs. We review recovery pathways for these streams, including supercritical water processing, solvometallurgy, hydrothermal/alkaline sulfide systems, and capture from ash and leachates, and outline policy and infrastructure actions to strengthen Sb oxide circularity and supply resilience.