复合膜材料在盐湖提锂中的研究进展和展望

Research progress and prospect of membrane method in seawater/brine extraction of lithium

  • 摘要: 锂电池新能源产业的快速发展刺激了锂需求量呈指数级增长,带动了锂产业链的变革和技术升级。盐湖卤水中拥有丰富的锂资源,已逐渐取代锂辉石成为原料锂的最主要来源。综合比较卤水提锂采用的沉淀法、吸附法、煅烧浸取法、萃取法、膜分离法等各种工艺,膜分离方法具有常温下无相变、高效、节能、环保的特点,成为提锂工业最有前景的新技术。目前,具有锂分离效果的膜过程研究主要有膜-吸附、膜-溶剂萃取和膜-电渗析等,其中又以膜-电渗析技术较为成熟,在工业上已经成功应用于盐湖卤水提锂。但目前采用的有机聚合物膜存在的膜堵塞、有机物溶损、环境污染等问题,限制了膜-电渗析法在提锂产业的推广。无机陶瓷膜按孔径分为微滤、超滤和纳滤,分离过程主要基于“物理筛选”理论,并且无机陶瓷膜材料具有化学结构稳定、力学性能好、制备过程简单、耐高温、孔径均匀、孔径分布范围窄、寿命长等众多优点,因此新型无机膜材料开发引起了学界的广泛关注,成为膜法提锂研究的热点问题。

     

    Abstract: With the widespread promotion of new energy electric vehicles for lithium batteries worldwide, the demand for lithium is surging. And the industry chain of lithium is in the process of technological transformation and upgrading, the extraction of lithium from salt lake brine is becoming the main source. Comprehensively compare the precipitation method, adsorption method, calcining leaching method, extraction method, and other processes used in the extraction of lithium from brine, membrane separation is a high-efficiency and energy-saving separation and purification technology without phase change at room temperature, and it has become the most promising energy-saving and environmentally-friendly new technology in the lithium extraction industry. At present, the research on membrane processes with lithium separation effect mainly includes membrane-adsorption, membrane-solvent extraction and membrane-electrodialysis, etc. And membrane-electrodialysis technology has been successfully applied to extract lithium from salt lake brine in industry. However, the existing shortcomings of organic membranes, such as membrane blockage, organic matter dissolution loss, and environmental pollution, limit the promotion of membrane-electrodialysis in the lithium extraction industry. Inorganic ceramic membranes are divided into microfiltration, ultrafiltration and nanofiltration according to the pore size. The separation process is mainly based on the “physical screening” theory, and the inorganic ceramic membrane material has stable chemical structure, good mechanical properties, simple preparation process, high temperature resistance, uniform pore size, It has many advantages such as narrow pore size distribution range and long life. Therefore, the development of new inorganic membrane materials has attracted widespread attention from the academic community and has become a hot issue in the study of lithium extraction by membrane methods.

     

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