Structural Destruction of As–Sb Solid Solution through a Selective Oxidation Process in the Presence of CaO and Its Effect on As Removal from the As–Sb Dust

摘要

As–Sb dust from metallurgical processes causes serious environmental issues due to the presence of the toxic element As. In this study, a facile method for removing As through the destruction of the As–Sb solid solution structure from the dust using CaO under an oxidizing atmosphere was processed. The effects of the variables, including the amount of CaO added, roasting temperature and time, and oxygen partial pressure, on the volatilization of As and Sb were investigated. Under an oxidizing atmosphere in the presence of CaO, the formation of the vitreous material (As–Sb–O) was hindered through the transformation of Sb2O3 and (As, Sb)2O3 in the untreated dust into Sb2O4, Sb2O5, Sb6O13, and Ca2Sb2O7, and the volatilization of arsenic was promoted, as a result. The volatilization attained for As was 91.53% whereas that for Sb was only 4.30% under the following optimum conditions: 5 mass % CaO, a roasting temperature of 550 °C, an O2 partial pressure of 21 vol % (air), and a roasting time of 80 min.