Ionic liquid metallurgy: novel electrolytes for metals extraction and refining technology

Ionic liquids (ILs) are molten salts that are liquid at or below room temperature. ILs have some unique properties compared to aqueous solution and regular organic liquids. These properties include very low vapor pressures and not emitting organic vapor to the environment; low melting points and wide temperature ranges for the liquid phase (up to 400 degrees C); and broad electrochemical windows, and they are environmentally benign. In this paper, a number of potential applications of ionic liquids in materials and metallurgical fields are investigated. Their application in the extraction of metals from primary and secondary sources was particularly emphasized. These applications include electrodeposition of metals/alloys, electrolytic extraction of active metals at room temperature, liquid-liquid extraction of metals and electrorefining of metals. Along with physical, chemical and thermodynamic properties of ionic liquids, the paper also discusses the merits and demerits of using ionic liquids in extraction of metals from various sources.