Production method of goethite
US5139767A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 4, 1991 |
| Grant date | Aug 18, 1992 |
| Priority date | — |
| Expiry date | Jan 4, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/22
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for producing goethite having an axial ratio of at least 7 and a specific surface area of 20-80 m.sup.2 /g and suitable for use in the production of .alpha.-iron powder, which method comprises intermittently feeding an oxidizing gas into a suspension of ferrous hydroxide, which has been obtained by reacting a ferrous salt with an alkali hydroxide, preferably while controlling the oxidation rate of ferrous hydroxide below 7% per each feeding-feed-stopping cycle of the oxidizing gas and also controlling the feeding time period of the oxidizing gas within 10 minutes and shorter than a quarter of the feed-stopping time period per each feeding-feed-stopping cycle of the oxidizing gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.