一步氨法净化铝电解烟气中氟盐的分离和转化

Separation and conversion of fluoride salts in aluminum electrolysis flue gas by one-step ammonia purification

铝电解烟气中含有氟化物、二氧化硫和二氧化碳等多种污染物,对环境和人类都有危害。目前,对于铝电解烟气净化技术的研究未涉及碳资源的回收,为了解决这个问题,本文提出了一种铝电解烟气一步净化技术。它是一种实现氟化物、SO_(2)和CO_(2)的净化并将废气污染物转化为冰晶石和复合氨肥资源转化的技术,将铝电解烟气经一步氨法净化后的含氟化铵吸收液,通过加入氢氧化钠和氢氧化铝进行化学沉淀生成冰晶石。通过使用氟离子电极、XRD和SEM等分析和检测,获得了最佳操作参数:温度为70℃、搅拌速度为400 r/min、反应物浓度为0.5 mol/L、α_(k)(NaOH与Al(OH)_(3)的分子比)为3.1。

The presence of multiple pollutants such as fluoride, SO_(2), and CO_(2) in aluminum electrolysis flue gas is harmful to the environment and human beings. The current research on aluminum electrolysis flue gas purification does not involve recovering carbon resources. We propose a one-step purification technology for aluminum electrolysis flue gas purification to address this problem. It is a resource conversion technology that integrates the purification of fluoride,SO_(2), and CO_(2) and converts the exhaust pollutants into cryolite and compound ammonia fertilizer. This paper studies an ammonium fluoride-containing absorption solution after one-step ammonia purification of aluminum electrolysis flue gas. It generates cryolites by adding NaOH and Al(OH)_(3) for chemical precipitation. The optimal operating parameters were obtained by using a fluoride ion electrode, XRD and SEM analysis and detection, under the condition of temperature of 70 ℃, stirring speed of 400 r/min, reactant concentration of 0.5 mol/L, and α_(k)(molecular ratio of NaOH to Al(OH)_(3)) of 3.1.