膦酸基低共熔溶剂浸出钴酸锂中的金属元素

Leaching metal elements from lithium cobalt oxide with phosphate acid-based deep eutectic solvent

以氯化胆碱为氢键受体,苯基次膦酸为氢键供体,制备膦酸基低共熔溶剂(DES),研究其浸出钴酸锂的性能。考察了浸出温度、液固比、浸出时间等因素对浸出率的影响,利用缩核模型拟合了浸出动力学数据,采用紫外-可见吸收光谱和红外吸收光谱分析了浸出机理。结果表明:增加浸出时间、液固比,升高浸出温度(70~90℃),可提高锂和钴的浸出率。浸出过程受化学反应控制,浸出锂和钴的表观活化能分别为26.5 kJ/mol和26.6 kJ/mol。钴酸锂的浸出液中,钴的配位构型为四面体,P=O参与了钴的配位。

A deep eutectic solvent(DES) composed of choline chloride(hydrogen bond donor) and phenylphosphinic acid(hydrogen bond donor) was prepared, and the leaching performance of lithium cobalt oxide using the DES as lixiviants was studied. The effects of leaching temperature, liquid-to-solid ratio and leaching time on leaching efficiencies were investigated. The leaching kinetics data were fitted by the shrinking core model,and the leaching mechanism was analyzed by UV-Vis absorption spectrum and FTIR spectrum. The results show that the leaching efficiencies of lithium and cobalt increase with the increase of leaching time, liquid-solid ratio and leaching temperature(70-90 ℃). The leaching process is controlled by chemical reaction and the apparent activation energy values for lithium and cobalt are 26.5 kJ/mol and 26.6 kJ/mol, respectively. In the leaching solution of lithium cobalt oxide, the coordination configuration of cobalt is tetrahedral and oxygen atom in P=O coordinate to cobalt.