摘要
NdFeB废料湿法回收技术中常采用中和除铁后萃取分离的方式进行酸浸液中有价元素的有效回收,传统方式工艺过程中不可避免的存在有价元素损失、二次废水污染的问题。基于绿色环保理念,优化现有工艺流程,探索一种离子液体萃取分离Fe/Co的方法,使Fe,Co元素能够较好分离,实现NdFeB废料的绿色回收。基于未经稀释的离子液体Aliquat336在高氯酸度条件下萃取Fe,Co不萃取稀土的特点,通过NH_(4)^(+),Cl^(-)含量的调节,可实现Fe萃取的同时Co仍位于水相中,最终达到Fe,Co,稀土的分离。Fe在萃取过程中与Aliquat336的结合能力更强,因此较短的反应时间即可达到萃取平衡,这也是Fe能够优先萃取的重要原因之一。经实验得Fe与Aliquat336的萃取机制为离子络合,络合比为1∶1,相关FTIR(傅里叶红外光谱仪)表征显示Co与Aliquat336的萃取机制与Fe相同。由于Aliquat336萃取Co时可能是以较为复杂的钴铵氯络离子的形式进行的,因此在优先萃取Fe后需补充一定量的NH_(4)^(+),Cl^(-)才能实现Co的萃取。经相关实验得:在实际NdFeB盐酸浸出液中,Fe的最佳萃取率达97.66%;在Fe萃取后进行Co的萃取,其最佳萃取率可达92.13%。
In the hydrometallurgical extraction technology of NdFeB waste,the extraction method after neutralization and deironing is often used to effectively recover the valuable elements in the acid leaching solution.In traditional methods,valuable elements will inevitably be lost and cause secondary wastewater pollution.Based on the concept of green environmental protection,optimizing the existing process flow and exploring the method of ionic liquid extraction and separation of Fe/Co,can separate Fe and Co and realize the green recovery of NdFeB waste.Based on the feature that the undiluted ionic liquid Aliquat336 extracts Fe and Co without extracting rare earths under the condition of perchloric acidity,by adjusting the content of NH_(4)^(+)and Cl^(-),the extraction of Fe can be achieved while Co is still in the water phase.Eventually the separation of Fe and Co,and rare earths is achreved.Fe has a stronger binding ability with Aliquat336 during the extraction process,so a shorter reaction time can reach the extraction equilibrium,which is one of the important reasons why Fe can be extracted preferentially.According to the experiment,the extraction mechanism of Fe and Aliquat336 is ion complex,and the complex ratio is 1∶1.Correlation FTIR(Fourier Infrared Spectroscopy)characterization shows that the extraction mechanism of Co and Aliquat336 is the same as Fe.Since Aliquat336 may be used to extract Co in the form of complex cobalt ammonium chloride ion,a certain amount of NH_(4)^(+) and Cl^(-)must be supplemented after preferential extraction of Fe to achieve the extraction of Co.Relevant experiments show that:in the actual NdFeB hydrochloric acid leaching solution,the optimal extraction rate of Fe reaches 97.66%;the extraction of Co after Fe extraction,the optimal extraction rate can reach 92.13%.
作者
赵永志
帅国胜
马莹
Zhao Yongzhi;Shuai Guosheng;Ma Ying(State Key Laboratory of Baiyunobo Rare Earth Resource and Comprehensive Utilization,Baotou Research Institute of Rare Earths,Baotou 014030,China;College of Chemistry and Chemical Engineering,Inner Mongolia University,Hohhot 010020,China)
出处
《中国稀土学报》
EI
CAS
CSCD
北大核心
2022年第3期450-458,共9页
Journal of the Chinese Society of Rare Earths
基金
科技部国际合作交流项目(白云鄂博稀土资源研究与综合利用国家重点实验室)(2020Z2137,2020Z2208)资助。
