Method and apparatus for dissociating metals from metal compounds extracted into supercritical fluids
US6132491A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 1998 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Aug 20, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/54
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.