柠檬酸-赤泥联用高效脱除电解锰渣氨氮的工艺及机理研究

Study on process and mechanism of efficient removal of ammonia nitrogen from electrolytic manganese residue by citric acid and red mud

电解锰渣中氨氮限制了其资源化利用,柠檬酸酸-赤泥联用可高效彻底脱除电解锰渣中氨氮。本文研究处理剂用量、反应时间和浸取方式等工艺条件对电解锰渣中氨氮剩余浓度的影响,通过XRD和XPS等技术表征物质变化,探讨氨氮脱除机理。结果表明,柠檬酸浸出工序是柠檬酸用量25%、液固比为5:1条件下机械振荡浸出30min;赤泥深度脱除工序是电解锰渣与赤泥质量比为1:0.5、室温浸取5h,电解锰渣中氨氮残存浓度降至1mg/L左右。浸出液中的铵根离子与柠檬酸反应最终生成柠檬酸铁铵稳定于浸出液中。赤泥中的碱性物质与残存氨氮反应,氨氮以气体形态脱除。

Ammonia nitrogen in electrolytic manganese residue limits its resource utilization.The combination of citric acid and red mud can efficiently and completely remove ammonia nitrogen from electrolytic manganese residue.In this paper,the effects of process conditions such as dosage of treatment agent,reaction time and leaching method on residual concentration of ammonia nitrogen in electrolytic manganese residue are studied.The substance changes are characterized by XRD and XPS techniques and the mechanism of ammonia nitrogen removal is discussed.The results show that the leaching process of citric acid involves oscillation leaching for 30 minutes under citric acid dosage of 25%and liquid-solid ratio of 5:1.The deep removal process of red mud involves leaching at room temperature for 5 hours under electrolytic manganese residue to red mud mass ratio of 1:0.5,and the residual concentration of ammonia nitrogen is reduced to about 1mg/L.The ammonium ions in the leaching solution react with citric acid to form ammonium ferric citrate,which is stabilized in the leaching solution.The alkaline substances in the red mud react with the residual ammonia nitrogen,and the ammonia nitrogen is removed in a gaseous form.