An ion-pair extraction system constructed for the separation of lithium, magnesium and boron

Lithium and boron are important strategic resources related to national defense and people’s livelihood. We invented an acidic extraction system N221 for simultaneous extraction of lithium and boron. However, in the process of extracting Li + from acidic extraction system, the pH of the system will inevitably decrease, which will increase the acidity during stripping. Therefore, we propose to add N235 to N221 to form an ion-pair extraction system, so that Li + can enter the organic phase in the form of neutral compound LiCl. The results show that the ion pair system can effectively improve the pH of the system and increase the operating pH range during stripping, and it is not necessary to use acid for stripping. This not only avoids the corrosion of equipment by the use of acid, but also avoids the harm to the environment caused by the use of acid. And the addition of N235 effectively reduced the Mg/Li ratio. Besides, N221 extractant has good regeneration performance and can meet the later industrial practical application. This experiment overcomes the shortcomings of N221 system, and it can be foreseen that this study also has broad application prospects in recovering lithium from spent lithium-ion batteries.