Abstract:Arsenic trioxide was prepared from arsenic-bearing dust through leaching with NaOH solution and reduction with sulfur dioxide. The results show that arsenic leaching rate is 99.27% under the conditions including concentration of NaOH solution of 3.0 mol/L, mass ratio of sulfur to arsenic-bearing dust of 0.075︰1, L/S of 6︰1, leaching time of 2.0 h, leaching temperature of 95 ℃, and agitation speed of 400 r/min. As2O3 content in reduction product is 95.79% with arsenic recovery of 86.13% under the conditions including initial concentration of arsenic of 100 g/L, initial pH value of 0, reaction temperature of 30 ℃, reaction time of 90 min, flow rate of SO2 of 0.8 L/(L?min), and agitation speed of 300 r/min. After dissolving in hot water and recrystallization, As2O3 purity is 99.63%, which meets the first grade standard of Nonferrous Metal Industry of China (YS-T99—1997).