Study on separating arsenic and antimony by NaOH alkali leaching of arsenic and antimony soot

The arsenic and antimony soot produced during the fire treatment of lead anode slime is harmful to the environment, but antimony as a valuable metal needs to be recycled. Thus, separating arsenic and antimony soot has practical significance. In this study, the separation of arsenic and antimony soot was studied by alkaline leaching at atmospheric pressure. Firstly, the effect of hydrogen peroxide on separating arsenic and antimony in the atmospheric alkali leaching process was investigated. The results showed that the effect was not so obvious that no oxidizing agent was used in the subsequent alkaline leaching. Secondly, the effects of leaching temperature, NaOH concentration, liquid-solid ratio and leaching time on the separation of arsenic and antimony were investigated. The results showed that under the conditions of 70 ℃, NaOH concentration of 60 g/L, liquid-solid ratio(mL/g) of 4:1, constant stirring speed of 400 r/min, and leaching for 90 min, the leaching rate of arsenic and antimony reached 93.92% and 2.74%, which indicated that this process could achieve the aim of effective separation of arsenic and antimony.