Basic Study on Distribution Behavior of Platinum Group Ions Using TPPS-[Cnmim][Tf2N] in Hydrochloric Acid Medium

Abstract

Although solvent extraction has been used in the recovery of rare metals from urban mines, some challenges remain. For example, large amounts of organic solvent are required for Pd (II) separation owing to the slow extraction kinetics of dihexylsulfide (DHS). This lengthens the separation process and increases the evaporation loss of diluents. In our previous work, we found that Pd (II) quickly separates from a hydrochloric acid medium using triphenylphosphine as a phosphorus-based extractant. In this work, we investigate the extraction and backextraction behavior of Rh (III), Pd (II), and Pt (IV) in a hydrochloric acid medium using the combination of triphenylphosphine sulfide (TPPS) and ionic liquids (ILs). Results show that the extraction mechanism of Pd (II) is based on the cooperative extraction effect of TPPS and ILs. Additionally, it was confirmed that the third phase during Pd (II) extraction was inhibited using TPPS-ILs. Furthermore, this study investigated the separation behavior of Rh (III), Pd (II), and Pt (IV) from a hydrochloric acid medium using TPPS-ILs as an extractant and a multiple back-extractant.

Keywords

• platinum group elements
• urban mine
• solvent extraction
• ionic liquid
• tpps