The fusion of the leaching and purification processes was realized by directly using microemulsion as the leaching agent. The bis-(2-ethyhexyl) phosphoric acid (DEHPA)/ n -heptane/NaOH microemulsion system was established to directly leach vanadates from sodium-roasted vanadium slag. The effect of the leaching agent on the leaching efficiency was investigated, in addition to the molar ratio of H 2 O/NaDEHP ( W ), DEHPA concentration, solid/liquid ratio, stirring time, and leaching temperature. In optimal situations, the vanadium leaching efficiency reaches 79.57%. The X-ray diffraction characterization of the leaching residue and the Raman spectrum of the microemulsion before and after leaching demonstrate the successful entry of vanadates from the sodium-roasted vanadium slag into the microemulsion. The proposed method successfully realizes the leaching and purification of vanadates in one step, thereby greatly reducing production costs and environmental pollution. It also offers a new way to achieve the green recovery of valuable metals from solid resources.
Hai Liu,Ke Xue,Wenguang Zhu,Dingchao Fan,Zihao Dong,Yinglong Wang,Jianguang Qi,Zhaoyou Zhu,Peizhe Cui
This work introduces a sustainable and environmentally friendly process for extracting cobalt from leach solution of waste lithium-ion batteries, which can effectively reduce environmental pollution and alleviate shortage in cobalt resources. Three kinds of hydrophobic deep eutectic solvents (HDESs) were synthesized using di-(2-ethylhexyl) phosphate (DEHPA) as a hydrogen bond acceptor (HBA) and 1-butanol, 1-hexol and 1-octanol as hydrogen bond donors (HBD), which were cheap and easy to obtain and had little pollution to water. Among them, 1-butanol had the best extraction efficiency. At an extraction time of 6 min, O/A of 2:1, and pH of 5, the single extraction efficiency of 1-butanol-DEHPA for cobalt reached 95.64 %, which was higher than that when DEHPA was used alone, and the required amount of DEHPA was reduced. Furthermore, HDES exhibited good recycling ability. After five cycles of extraction, the extraction efficiency of HDES for cobalt remained above 80 %. The possible extraction mechanism was explored using the slope method, Fourier transform infrared spectroscopy , and hydrogen nuclear magnetic resonance spectroscopy . Through quantum chemical calculation and optimization, it has been demonstrated that a cation exchange exists between HDESs and cobalt ions , and non-extractive components play an important role in the extraction process. These findings will contribute to the development of environmentally friendly HDESs and improvement of cobalt recovery technology. Additionally, they will contribute to environmental protection and reduction of environmental pollution.
危险品化学品经营许可证（带存储）