废旧镍氢电池酸浸液中稀土的萃取研究

Research on Rare Earths Extraction from Acid Leaching Solution of Spent Nickel-Metal Hydride Batteries

采用溶剂萃取的方法,对从废旧镍氢电池酸浸液中选择性提取稀土进行了探索。实验探索出合适的萃取体系,研究了料液初始pH值、萃取温度、混合强度、萃取时间、萃取相比等因素对萃取效果的影响,考察了反萃剂组成、浓度、反萃相比等因素对反萃效果的影响,并测出稀土的萃取等温线。在此基础上进行了工厂扩大试验,结果表明:经5级逆流萃取,稀土的萃取率可达99.99%。混合反萃液经草酸沉淀,得到的稀土纯度为98.49%,杂质金属含量均小于0.05%。所选萃取有机相对稀土有良好的选择性,可实现稀土与其他元素的分离。

Investigation was made of selective extraction of rare earths from the acid leaching solution of spent nickel-metal hydride batteries by solvent extraction. A suitable extraction system was established. Study was made of the effects of the factors such as the initial pH value of raw material liquid, extraction temperature, mixing intensity, extraction time, extraction phase ratio on the extraction efficiency, as well as the effects of such factors as the stripping agent composition and concentration, and stripping phase ratio on the stripping efficiency. In addition, the extraction isotherm of rare earths was measured. Based on the research, pilot-plant experiment was conducted. The results show that the extraction rate of rare earths can reach 99.99 % by five-stage countercurrent extraction. Through the precipitation of the mixed stripping solution with oxalic acid,the rare earths with a purity of 98.49% can be obtained and the contents of all the metallic impurities are less than 0.05 %. The chosen extraction organic phase has a good selectivity for rare earths to ensure the separation of rare earths from other elements.