Separation behavior of metal and oxide: Vacuum gasification for metal recovery advanced from lead anode slime

Lead anode slime (LAS), a significant secondary resource, was utilized to separate andrecycle of rare and precious metals such as Te, Au, and Ag, along with essential metals Cu, Pb, and Bi. The conventional pyrometallurgical and hydrometallurgical processes generated hazardous waste, including high levels of As, Sb, smoke, heavy metal waste. Extraction of these key metals is both laborious and ineffective. A novel vacuum gasification technology was employed to explore the separation patterns and migration distribution principles of metal and oxide (MO) in LAS. The theoretical results of phase transition enthalpy change (Delta H), saturated vapor pressure, and molecular average free path investigated the gasification and volatilization potential of MO in LAS. Furthermore, the experimental results revealed separation behavior of MO. As and Sb were evaporated into the gaseous phase to facilitate their separation from other substances at 773 K. Pb and Bi behavior were similar to them at 823 K, As, Sb, Pb and Bi to enter the gaseous phase for the purpose of separation with Ag, Au, and Cu. By exploiting the differences of gasification specificity, it is possible to separate Ag, Au, Cu, and other elements at 1173 K, finally leading to the formation of Ag-Au-Cu alloys.