Fluid extraction using carbon dioxide and organophosphorus chelating agents
US5840193A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1996 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Jul 26, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/912
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.