Dehydration of hydrous oxides

Temperature and air feed is carefully controlled in the process to suppress any formation of antimony tetroxide (86204). Antimony trioxide is separated from any arsenic trioxide (AS2O3) that may be present as an impurity by volatilization, as the latter is much more volatile than the former. It may be also prepared by alkaline hydrolysis of antimony trichloride and subsequent dehydration of hydrous oxide under controlled heating (rapid or vigorous heating may partially oxidize 8b(III) to Sb(V). 

---