Separation of Arsenic from the Antimony-Bearing Dust through Selective Oxidation Using CuO

A pyrometallurgical process of selective oxidation roasting of the antimony-bearing dust using CuO is put forward, in which the antimony component is oxidized to Sb₂O₄ staying in the roasted residue, and arsenic is volatilized in the form of As₂O₃. The addition of CuO has an active effect on the arsenic volatilization, because structures of some complicated As-Sb phases in the dust are destroyed after the “Sb” component in them is oxidized to Sb₂O₄, and this part of arsenic might be transformed to As₂O₃, which continues to volatilize. However, the arsenic volatilization rate decreases with the CuO amount in a certain range, which is attributed to the greater formation of Cu₃ (AsO₄)₂ and Cu₃As. Under the conditions of roasting temperature of 673 K (400 °C), roasting time of 100 minutes, CuO amount of 34.54 mass pct, and N₂ flow rate of 30 mL/min, 91.50 pct arsenic and only 8.63 pct antimony go into the smoke.