Magnetic field-assisted pulse chromatography for simultaneous in situ extraction of uranium and lithium from salt lake

Salt lake is a huge treasure trove of resources, and the separation and extraction of metal resources such as uranium and lithium from situ salt lake water can effectively alleviate the problem of energy shortage. In this study, an automated pulsed liquid chromatography separation device based on magnetic field assistance was invented for the efficient extraction of key metals such as uranium and lithium from salt lake water. The device adopts a unique flow-air-flow dynamic pulse injection mechanism, and uses a 10 meter chromatographic column filled with Polymethyl methacrylate pellets (average diameter of 1.0 millimeter) to provide multiple effective separation units, which dramatically improves the separation efficiency. The chromatographic column has good resistance to both acids and bases. The flow rate of the solution in the column was 16 mL/min, and the pulse volume of a single separation was 20 mL. The column remained normal after withstanding more than 6000 pulses from the salt lake, with a long service life and good cyclability. By optimizing the assistance of the magnet, the simultaneous separation and extraction of uranium and lithium from the in situ salt lake was finally achieved with the assistance of a ring magnet. The experimental results show that the magnesium-lithium separation factor is 1.202, and the uranium-lithium separation factor is 1.088. Theoretically, a solution with a magnesium-lithium ratio of 200 can be reduced to 20 by only 13 stages of separation. Columns with glass pellets as packing materials were compared to examine the effect of functional groups and to verify the presence of liquid membrane. The mechanism of ion movement on the packing surface under the combined effect of magnetic field and liquid membrane was analyzed in depth. The results showed that the pulsed chromatography combined with magnetic field can significantly improve the simultaneous extraction efficiency of uranium and lithium from the salt lake, which provides a new research idea and technical experience for the industrial application in the field of chromatography and the extraction of resources from the salt lake.