球形PVC-MnO2离子筛的制备及锂吸附性能

本实验室前期所制备的Li4Mn5O12超细粉末在卤水体系中对Li+具有较大的吸附容量和良好的选择性。但由于超细粉体的流动性和渗透性差,无法直接应用于固定床,需对粉末吸附材料进行成型造粒,以便于实际应用。本论文采用聚氯乙烯为粘结剂,制备出粒径约为2.0~3.5 mm的球形PVC-Li4Mn5O12,经盐酸处理后得到球形PVC-MnO2离子筛。并通过扫描电镜(SEM)、X射线衍射仪(XRD)、静态和动态连续锂吸附实验研究了球形离子筛形貌和锂离子吸附性能。结果表明,球形离子筛对Li+的吸附容量高达5.28 mmol.g-1,在混合溶液中对Li+具有良好的选择性,这对于在盐湖卤水或海水提锂具有重要的实用意义。

Preparation of Spherical PVC-MnO2 Ion-Sieve and Its Lithium Adsorption Property

Ultrafine powder Li₄Mn₅O₁₂ prepared by our lab has a high adsorption capacity and selectivity for Li⁺ in brine (containing Li⁺, Na⁺, K⁺ and Mg²⁺). However, in the practical application, the ultrafine powder should be formed into the granular adsorbent materials in order to be packed in column with a lower pressure drop of fluid flowing. In this paper, the spherical PVC-Li₄Mn₅O₁₂ ion-sieve with particle diameter 2.0~3.5 mm was prepared, where using Li₄Mn₅O₁₂ ultrafine powder as ion-sieve precursor, poly vinyl chloride (PVC) as binder. And it was treated with HCl solution to obtain spherical PVC-MnO₂ ion-sieve. The prepared spherical ion-sieve was characterized by Scanning Electron Microscopy (SEM) and X ray Diffraction (XRD). The adsorption/desorption behavior for lithium ion was evaluated by the experimental measurements in the batch and fixed bed adsorbers packed with the spherical PVC-MnO₂ ion-sieve. It was found that the prepared spherical ion-sieve well maintained the excellent adsorption behavior of the ultrafine powder with a high Li⁺ adsorption capacity of 5.28 mmol·g^-1, and also it has a high Li⁺ selectivity when recovering Li⁺ from the solution containing Li⁺, Na⁺, K⁺, Mg²⁺. With the developed PVC granulation process, the prepared spherical PVC-MnO₂ ion-sieve (H type of PVC-Li₄Mn₅O₁₂) makes the ion-sieve adsorption potential application in industry for lithium recovery from brine or seawater.