<p>The present work studies the selective removal of arsenic from crude antimony trioxide (CATO) by an evaporation with airflow and a downstream antimony recovery through thermal decomposition and volatilization. The fundamental problem in selective arsenic removal is the liberation of arsenic oxide from antimony-arsenic oxide, which can be realized by oxidizing antimony trioxide to antimony tetroxide. The effect of evaporation temperature and duration time are studied on arsenic removal yield and antimony loss and the phase conversion of crude antimony trioxide. Afterward, we investigate the antimony recovery from purified CATO through thermal decomposition with and without carbon addition. It is found that the temperature dictates the arsenic removal yield, and the arsenic content drops from 1.5 wt.% to 0.4 wt.% after evaporation at 700 °C in 345&#xa0;mL/min airflow for 1&#xa0;h. The residual sample contains a single phase of cervantite, which starts decomposing to volatile Sb₄O₆ at a temperature above 996 °C. With the presence of carbon, the onset decomposition temperature of cervantite remarkably decreases to 569 °C.</p> Graphical Abstract <p></p>