An exemplary embodiment of the present disclosure provides a method to extract components from a metal-containing material, forming a first multicomponent system comprising an ionic liquid and a first aqueous component, wherein the first aqueous component and the ionic liquid form an immiscible mixture when the first multicomponent system is at a temperature below a critical temperature, contacting a metal-containing material with the first multicomponent system, adjusting the temperature of the first multicomponent system above the first critical temperature to form a miscible mixture with the ionic liquid and the first aqueous component, reverting the temperature of the first multicomponent system below the critical temperature to form an immiscible mixture with the ionic liquid and the first aqueous component, and isolating the ionic liquid from the first aqueous component and the metal-containing material, wherein the ionic liquid comprises one or more metals from the metal-containing material.

Rare earth elements and carbon rich solids are extracted from coal feedstock by combining a coal feedstock with an ionic liquid, forming a mixture. The mixture is heated and a co-solvent is added. Carbon rich solids and rare earth elements are removed from the solution. The ionic liquid and co-solvent may be reused.

A method for extracting at least one lanthanide element, preferably selected from lanthanum (La), praseodymium (Pr), neodymium (Nd), europium (Eu), dysprosium (Dy), and ytterbium (Yb), from a solid material including the lanthanide element, one or more waste elements such as iron (Fe), and/or one or more other lanthanide elements. The method implements a composition including water, at least one organic aprotic solvent, and at least one charged hydrotrope. Also, the use of the composition for recycling lanthanide elements, and more particularly WEEE, and for the decontamination of effluents.