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Method and apparatus for dissociating metals from metal compounds extracted into supercritical fluids

United States Patent

6,132,491
October 17, 2000
View the Complete Patent at the US Patent & Trademark Office
Idaho National Laboratory - Visit the Technology Transfer and Commercialization Office Website
A method for dissociating metal-ligand complexes in a supercritical fluid by treating the metal-ligand complex with heat and/or reducing or oxidizing agents is described. Once the metal-ligand complex is dissociated, the resulting metal and/or metal oxide form fine particles of substantially uniform size. In preferred embodiments, the solvent is supercritical carbon dioxide and the ligand is a .beta.-diketone such as hexafluoroacetylacetone or dibutyldiacetate. In other preferred embodiments, the metals in the metal-ligand complex are copper, silver, gold, tungsten, titanium, tantalum, tin, or mixtures thereof. In preferred embodiments, the reducing agent is hydrogen. The method provides an efficient process for dissociating metal-ligand complexes and produces easily-collected metal particles free from hydrocarbon solvent impurities. The ligand and the supercritical fluid can be regenerated to provide an economic, efficient process.
Wai; Chien M. (Moscow, ID), Hunt; Fred H. (Moscow, ID), Smart; Neil G. (Workington, GB), Lin; Yuehe (Richland, WA)
Idaho Research Foundation, Inc. (Moscow, ID)
09/ 137,563
August 20, 1998
ACKNOWLEDGEMENT OF GOVERNMENTAL SUPPORT The present invention was funded in part by the United States Department of Energy under Subcontract CC-S-588193 under Subcontract C95-175002 under contract DE-AC07-94ID13223; the United States government has certain rights in this invention.