Lithium and its compounds are important strategic resources for the economy and national defense construction. In the Chinese lithium industry, Qinghai old brine, which is the main source of Li + , contains Mg 2+ as much as 125.6743 g/L, and the effective separation of these two elements has been a challenging task. We designed and synthesized a benzene sulfonamide acid substance N221 with stronger acidity and steric hindrance to effectively extract Li + in high Mg/Li solution. The existing acidic extractants include P204, P507 and Cyanex272, among which N221 has the highest β Li/Mg value and E Li (%) value. The thermodynamic properties of the reaction between N221 and metal ions was explored by means of thermodynamic equilibrium constant and quantum chemical calculation. A large amount of Mg 2+ in salt-lake promoted the extraction of Li + , and the mechanism was revealed by mean of molecular dynamics simulations. After stripping, the final Mg/Li (mol/mol) decreased from 15.80 in the Qinghai old brine to 1.27, which meets the conditions of further refining and can obtain high-purity lithium products. A process for separating Li + from Mg 2+ by benzene sulfonamide acid substance is proposed in this study, and the reasons are explained in depth from the experiments and molecular dynamics simulations. Hence, it can be foreseen that this study also has broad application prospects in the recovery of lithium from spent lithium-ion batteries containing a variety of high-valence metal ions.
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.
危险品化学品经营许可证（带存储）