Integrated Removal of Calcium and Magnesium and Extraction of Lithium from the Mamicuo Salt Lake in Tibet Using a Pyrrole Fluoride-β-Diketone/TRPO Synergistic System

With the exception of thermodynamic function studies, which employed variable-temperature experiments within the 273 K to 323 K range, all other extraction investigations were conducted at ambient temperature (293 K). Synergistic extraction systems were prepared by dissolving extractant with synergist in kerosene according to their respective component concentrations. The pH of the brine was then adjusted using Na2CO3 and NaOH. The synergistic extraction system and aqueous phase were then mixed in a volumetric ratio within a separatory funnel and mechanically agitated at 300 r/min for 10 minutes. Subsequently, the loaded organic phase underwent back-extraction with HCl solution. Consequently, the samples obtained from each stage were subjected to analytical testing.The concentrations of multiple components (Ca2+, Mg2+, Li+, Na+, K+, B, SO42−) in the aqueous phase were determined using ICP spectrometry (iCAP 7000, Thermo Fisher Scientific) and atomic absorption spectrophotometry (A3F-12, Beijing Puxi). The total organic carbon (TOC) in the aqueous phase was determined by employing a TOC analyser (model TOC-2000, Shanghai Yuanxi). pH was measured with a pH meter (S220, Mettler Toledo). The analyses of Cl-, HCO₃⁻ and CO32− were conducted by means of volumetric titration.