The aqueous biphasic system (ABS) based on 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM][BF₄] and sodium chloride as salting-out agent has been utilized for an efficient extraction of cobalt (II) from neutral media without adding any complexing agents. Effects of different operational parameters, such as initial amounts of system components, the volume and the concentration of cobalt (II), the presence of coexisting ions such as lead (II), cadmium (II), copper (II), manganese (II), zinc (II) and nickel (II), and temperature influence, were extensively investigated. As a third phase, aqueous solutions containing different additives, like NaCl, NaPF_6, HCl, Na₂SO_4, NaH₂PO_4, were tested. It has been proven that the stripping of the metal complex from the IL phase by a regenerating solution containing chaotropic salt (NaPF₆) in three-phase extraction system not only improved the extraction efficiency, but also enabled to regenerate ionic liquid phase. The metallic content has been determined by inductively coupled plasma optical emission spectrometry (ICP-OES).

基于1-己基-3-甲基咪唑四氟硼酸盐[HMIM] [BF ₄ ]和氯化钠作为盐析剂的水性双相体系（ABS）已用于从中性介质中高效萃取钴（II）而不添加任何碱络合剂。不同操作参数的影响，例如系统组分的初始量，钴（II）的体积和浓度，共存离子的存在，例如铅（II），镉（II），铜（II），锰（II） ），锌（II）和镍（II）以及温度影响进行了广泛的研究。作为第三相，包含不同添加剂的水溶液，例如NaCl，NaPF _6， HCl，Na ₂ SO _4， NaH ₂ PO ₄经过测试。业已证明，在三相萃取系统中，通过含有离液盐（NaPF ₆）的再生溶液从IL相中去除金属络合物，不仅可以提高萃取效率，而且还可以再生离子液体。金属含量已通过电感耦合等离子体发射光谱法（ICP-OES）确定。