Salting-out induced three-liquid-phase separation of Pt(IV), Pd(II) and Rh(III) in system of S201−acetonitrile−NaCl−water

► A new system for three-liquid-phase extraction and one-step separation of Pt, Pd and Rh. ► Salting-out induced phase-splitting is the main driving force for three-liquid-phase partition of Pt, Pd and Rh. ► A micro-mechanism explains the influence of phase-forming behavior of three-liquid-phase system on mass transfer of PGM. ► Appearance of microscopic molecular aggregates accounts for the microphase enrichment of platinum metal ions.