Method for treating heavy-metal-containing wastewater using sulfidizing agent
US7264733B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 2002 |
| Grant date | Sep 4, 2007 |
| Priority date | — |
| Expiry date | Feb 15, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/912
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method and apparatus for treating heavy-metal-containing wastewater using a sulfidizing agent. Sulfidizing treatment is carried out by adding a sulfidizing agent to heavy-metal-containing wastewater, while detecting hydrogen sulfide gas generated from the wastewater, such as to maintain a state in which hydrogen sulfide gas is just starting to be generated from the wastewater. When separately recovering each of a plurality of metals from wastewater in which are mixed ions of the plurality of metals, there is repeated for each of the metals a process in which the acidity of the wastewater is adjusted to within a range suitable for the metal to be separated out and recovered, a sulfidizing reaction is carried out on that metal, and the metal sulfide produced is precipitated and filtered off.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.