Process and apparatus for producing high-purity lithium metal by fused-salt electrolysis

US4740279A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Jurgen Muller · Wulfen, DE
• Richard Bauer · Estacada, US
• Bernd Sermond · Lahr (Eifel), DE
• Eike Dolling · Mölln, DE

Key dates

• Filing date: Sep 12, 1986
• Grant date: Apr 26, 1988
• Expiry date: Sep 12, 2006

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C25C3/02
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

This invention relates to a process of producing lithium metal by the electrolysis of fused mixed salts comprising electrolyzing fused mixed salts consisting of lithium chloride and potassium chloride in a diaphragmless electrolytic cell, withdrawing molten lithium metal from the cell to a receiver and cooling the lithium metal which has been withdrawn. To decrease the content of impurities in a continuous process, molten mixture which rises in the interelectrode space in the cell and contains lithium metal is collected in an annular zone, which surrounds the top end of the cathode adjacent to the surface level of the molten mixture, said molten mixture is withdrawn from said annular zone through a siphon pipe and is supplied from the latter to a separating chamber, which communicates with the electrolytic cell and is sealed from the chlorine gas atmosphere in the electrolytic cell, electrolyte and lithium are separated in the separating chamber under a protective gas atmosphere, lithium metal is discharged from the separating chamber into a receiver under a protective gas atmosphere, and the electrolyte is recycled from the separating chamber to the electrolytic cell. An electroly…