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Most of arsenic in the stibnite enters the antimony oxide powder after a traditional volatilization smelting/roasting process and further transfers into an arsenic-alkali residue in the followed antimony smelting process. This transfer of arsenic poses a huge threat to the environment. Decreasing the As transfer, a new process is proposed in this paper including two stages of roasting with pyrite addition for As pre-removal from antimony oxide powder. First, at temperatures higher than 500°C in a nitrogen atmosphere, the As 2 O 3 , Sb 2 O 3 , and As-Sb solid solution in the antimony oxide powder were transformed to As-S and Sb-S compounds. Then with the oxidizing roasting process, which was carried out at the conditions of an air flow rate of 200 ml/min, roasting time of 90 min, roasting temperature of 550°C and pyrite dosage of 5 wt.%, the As-S compounds were oxidized to As 2 O 3  and volatilized with an As removal rate of 92.71%, while the antimony was transformed to nonvolatile high-valence compounds that remained in roasted residues with Sb loss rate of only 5.64%. Using this treated antimony oxide powder in the traditional antimony smelting process, the formation of arsenic-alkali residue and antimony loss can be decreased to a great extent.

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Arsenic pre-removal from antimony oxide powder by roasting with pyrite (FeS 2 ) for decreasing arsenic transfer and pollution in the followed antimony smelting process