Wenfeng Xue,Ronghao Liu,Xiaoxia Liu,Yangyang Wang,Ping Lv,Yanzhao Yang
The development of an environmentally friendly extractant for selective recovery of rare earth elements is critical but still faces significant challenges. Two low viscosity carboxylic acid based ionic liquids [A336][BTA] and [A336][OTA] were synthesized for selective extraction of Nd(III) from waste NdFeB magnets. First, the extraction behaviors of two kinds of ionic liquids were compared under different conditions, such as time, pH value of aqueous phase, dosage of ionic liquids, and concentration of salting-out agent. The optimal extraction condition of [A336][OTA] was optimized by response surface methodology, and the extraction efficiency reached 99.1%. The extraction mechanism was proposed as ion association by UV–Vis spectrum, IR spectrum and 1 H NMR, and was supported from that perspective of quantum chemical calculation. The extraction thermodynamics, kinetics and isothermal model were studied in detail. [A336][OTA] maintained an extraction efficiency of 95.6% even after seven cycles. The extractant shows good selective separation performance in waste NdFeB magnets, and is an extractant with good application prospect. This work has provided an environmentally friendly extractant for the recovery of Nd(III) from waste NdFeB magnets.
Ruihui Wu,Ronghao Liu,Xiaoxia Liu,Jianwei Zhang,Wenfeng Xue,Yanzhao Yang
The recovery of Nd(III) from NdFeB permanent magnets is gaining increasing attention. In the rare earth elements separation industry, wastewater produced through saponification has become a serious environmental problem. In this work, a novel non-saponification P350-N235 synergistic extraction system was established for the extraction of Nd(III) from nitric acid medium. Almost 100% of Nd(III) was extracted by using a P350-N235 system when the molar fraction (X) of P350 was 0.3. And the synergistic enhancement factor R max reached 60.03. Firstly, the effects of time, pH, volume ratio and other variables were investigated to determine the extraction behaviors. Response surface methodology (RSM) was used to optimize the extraction conditions. The mechanism of synergistic extraction was investigated by FT-IR, UV–vis, NMR methods and ESP maps, indicating that the composition of the extracted complex was Nd(NO 3 ) 3 ·(P350) 2.5 (N235) 2.5 . Then, the extraction thermodynamics and kinetics were also thoroughly investigated, the extraction process is demonstrated to be a spontaneously exothermic reaction. In the NdFeB leaching solution, the synergistic system showed excellent separation factor (β) for Nd/Sm (1.43), Nd/Gd (7.33), and Nd/Dy (9.81). Finally, after 5 cycles, the P350-N235 synergistic system maintained high extraction efficiency. In conclusion, this study overcame the saponification problem in traditional extraction techniques and proposed an environmentally friendly green extraction system.
危险品化学品经营许可证（带存储）