Process for chromium removal using an inorganic sulfur compound
US5336475A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 28, 1993 |
| Grant date | Aug 9, 1994 |
| Priority date | — |
| Expiry date | Jul 28, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F2103/16
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method has been devised for removing chromium ions from a chromium ion containing liquid and recovering chromium oxide in a usable form by (a) adjusting the temperature of the liquid to an optimal temperature to maximize reduction and simultaneous precipitation of the chromium oxide; (b) adding a reducing agent to the liquid to form a mixture, where the reducing agent is at least one inorganic sulfur compound selected from the group of sulfur compounds where sulfur is in the 4.sup.+ oxidation state; and (c) adjusting the pH of the mixture to a pH between 5 and 7; (d) optionally further adjusting the pH of the mixture to a pH between above 7 to 12; and (e) separating the chromium from the mixture.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.