Process for the production of black iron oxide pigments
US6302952A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 2000 |
| Grant date | Oct 16, 2001 |
| Priority date | — |
| Expiry date | Aug 18, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/64
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for the production of a black iron oxide pigment from Fe.sub.2 O.sub.3 hematite iron oxide which may be an impure oxide produced by the "Ruthner" process or by other means, or which may be a mineral hematite. The process may be used to upgrade poor quality synthetic or natural hematite, or to improve their performance as red pigments, by conversion to black pigment with subsequent oxidation of the magnetite so produced back to hematite. The process uses a low temperature aqueous slurry reaction in which the hematite is contacted with a soluble source of Fe(II) ions in the presence of a soluble source of Fe(III) ions in an aqueous alkaline medium to convert the same to Fe.sub.3 O.sub.4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.