粉煤灰中战略金属锂的回收研究进展

Research progress of recovery of strategic metal lithium from fly ash

随着锂电池行业的快速发展,中国锂原料对外进口的依赖程度逐年增加。从粉煤灰中回收锂,既可以缓解中国锂供应量严重不足的现状,又可以有效解决粉煤灰污染环境的问题。在分析比较锂矿石、盐湖卤水和粉煤灰的组成及其特点的基础上,从浸出和提取两个方面综述了目前粉煤灰回收锂的工艺技术。锂浸出工艺受粉煤灰浸出铝工艺的影响,目前已较为成熟,主要有酸法浸出和碱法浸出工艺。锂提取技术则受锂浸出工艺的影响,酸法浸出工艺的浸出液杂质元素比较多,提锂过程比较复杂,目前主要有溶剂萃取法、煅烧浸出法和吸附法;碱法浸出工艺的浸出液杂质元素简单,提锂相对容易,目前主要采用的是吸附法。由于粉煤灰浸出液与盐湖卤水的成分相似,因此借鉴盐湖卤水的提锂技术经验,开发适用于粉煤灰浸出液的提锂技术,是未来粉煤灰回收锂的主要研究方向。

With the rapid development of lithium battery industry,the dependence of lithium raw materials on imports in China has increased year by year.Recycling of lithium from fly ash can not only alleviate the serious shortage of lithium supply in China,but also effectively solve the problem of fly ash polluting the environment.On the basis of analyzing and comparing the composition and characteristics of lithium ore,salt lake brine and fly ash,the technology of recovering lithium from fly ash was reviewed from two aspects:leaching and extraction.The lithium leaching process was affected by aluminum leaching process from fly ash,and it was relatively mature at present,mainly including acid leaching and alkaline leaching.The lithium extraction technology was affected by lithium leaching process.The leaching solution from acid leaching process had many impurities,so lithium extraction process was relatively complex,and currently mainly including solvent extraction,calcination-leaching and adsorption method.The leaching solution from alkaline leaching process had few impurities,so lithium extraction process was easy,currently mainly including adsorption method.Because the components of fly ash leaching solution and salt lake brine were similar,it was the main research direction of lithium recovery from fly ash in the future to learn from the experience of lithium extraction from salt lake brine and develop lithium extraction technology suitable for fly ash leaching solution.