Recovery of Sb and Fe from Sb-bearing Slags through a Reduction Roasting Process with Low Density Polyethylene

Abstract

A novel method for treating the Sb-bearing slag using LDPE as a reductant under N₂ atmosphere is proposed. The H₂, CH₄ and C₂ (C₂H₆, C₂H₄, C₂H₂) are released quickly during the LDPE pyrolysis process, and some of them have escaped off the roasting system before the reaction with the Sb-bearing slag. The Sb, Pb and Fe phases in the original Sb-bearing slag could be selectively reduced to Sb₄O₆, Pb and Fe₃O₄ respectively by the pyrolysis gas at roasting temperature of 1000°C and LDPE amount of 25 wt%. The Sb₄O₆ could be separated and recovered effectively with the volatilization rate of 93.51% accompanying the Pb volatilization rate was only around 0.68% and the Fe phase was almost transformed into Fe₃O₄ retaining in the residue. Then the Fe₃O₄ can be separated and collected from the roasted residues using magnetic separation process.