Separation of As from high As-Sb dust using Fe2O3 as a fixative under O2-N2 atmosphere

A novel method to separate As from high As-Sb dust using Fe 2 O 3 as a fixative under an O 2 -N 2 atmosphere is proposed. Here, Sb is oxidised and converted to Sb 2 O 4 and FeSbO 4 that remain in the roasted residue, and As is volatilized in the form of As 4 O 6 . The Sb 2 O 3 can be selectively oxidised from the dust by using 21 vol% O 2 , but the formation of amorphous substance (As-Sb-O) hinders the effective separation of As and Sb. Adding Fe 2 O 3 hinders the amorphous substance formation and destroys the structure of the solid solution ((Sb, As) 2 O 3 ) in the raw material by converting the Sb component in it to FeSbO 4 . Therefore, the volatilization rates of As and Sb can reach up to 90.53% and only 13.20%, respectively at a roasting temperature of 723 K, roasting time of 90 min, an Fe 2 O 3 dosage of 15 mass%, and O 2 content of 21 vol%.