Mechanism of Selective Arsenic Purification via Reductive Vacuum Sublimation: From Oxygenated Crude Arsenic to High‐Purity Arsenic

ABSTRACT Arsenic presents a critical duality as both a hazardous environmental pollutant and an indispensable material for advanced semiconductor technologies. This study proposes an integrated reductive vacuum sublimation strategy, assisted by carbon and lead additives, to purify crude arsenic containing high oxygen (7.4%) and antimony (1326 mg kg −1 ). Through systematic optimization of temperature (773–873 K) and pressure (0.01–100 Pa), oxygen content was reduced to < 0.1% and antimony to 93 mg kg −1 , yielding 4N‐purity (99.99%) crystalline elemental arsenic. Phase and chemical state evolution were confirmed, illustrating the complete reduction of As 2 O 3 and effective separation of Sb. Molecular dynamics (MD) and density functional theory (DFT) simulations further provide atomistic evidence for the separation mechanism beyond thermodynamic predictions, showing that As 4 species exhibit faster interfacial diffusion and weaker binding on Pb surfaces than Sb 4 , whereas Sb 4 interacts more strongly with Pb, thereby hindering its volatilization and enhancing the selective sublimation of arsenic. This integration of process engineering with molecular‐level theory validates an efficient, scalable pathway to transform hazardous arsenic waste into high‐purity material essential for optoelectronics, photovoltaics, and high‐speed semiconductor devices.