Removing metals from aqueous waste streams
US5785863A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1997 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Oct 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/912
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
Methods of removing contaminant metals from aqueous waste streams. A preferred method includes providing an aqueous waste stream containing a metal having a valence of at least one, such as zinc, lead, chromium, copper, iron, aluminum, manganese, cadmium, gold, silver, and mixtures of these metals. The waste stream is substantially free of calcium and magnesium. The process also includes forming a substantially insoluble precipitate of said metal by mixing with the waste stream fatty acids; zinc, potassium, and sodium salts of fatty acids; and mixtures of these materials. The metal precipitate is separated from the waste stream and the water that is subject to the removal process remains substantially free of calcium and magnesium throughout the entire process. The methods of the present invention are particularly effective for the removal of trace amounts of zinc from aqueous waste streams from polystyrene processes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.