Abstract:Selective-leached residue of copper smelting dust was intensity directly leached with oxygen and precipitation separation. The results show that leaching rate of bismuth is 93% above under the optimum conditions including concentration of hydrochloric acid of 2 mol/L, sodium sulfate of 1.5 times of theoretical amount, reaction temperature of 75 ℃, reaction time of 3 h, and ratio of liquid to solid of 3︰1. High purity bismuth oxide can be prepared.