Chrome removal and recovery
US4054517A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 13, 1976 |
| Grant date | Oct 18, 1977 |
| Priority date | — |
| Expiry date | Feb 13, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/913
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
The present invention is directed to a process for removing and optionally recovering hexavalent chromium from chromium waste water. The invention involves the use of a treatment mixture comprising the combination of barium carbonate and/or barium hydrate, plus one or more certain specified acetates. The process involves contacting the chrome waster water to be treated with the treatment mixture at an acetic pH not exceeding 6.0, and usually from 4.0 to 6.0, followed by filtration through an acid-resistant filter. The chromium removed by this filter in the form of barium chromate can be regenerated into chromic acid by backwashing the filter into an agitated tank and treating to produce chromic acid and barium sulfate. The thus-generated chromic acid can then be returned to the chrome plating tank for reuse after passing through a filter to remove the barium sulfate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.