Method for the preparation of acicular particles containing iron and other divalent metals
US3994819A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1975 |
| Grant date | Nov 30, 1976 |
| Priority date | — |
| Expiry date | Sep 5, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2004/62
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention concerns the preparation of acicular particles of mixed oxalates of iron and of one or more metals of the group consisting of cobalt, nickel, copper, manganese, zinc, magnesium and cadmium. The method consists in preparing a first solution containing cations of iron and of the divalent metal or metals, and a second solution containing oxalic acid, one of the said solutions further containing Cl.sup.- and SO.sub.4.sup.2.sup.- anions and at least the second solution containing alcohol with preferably a light hydrocarbon. The first solution is poured very slowly (1 drop every 10 seconds) into the second one, conveniently at temperature below 0.degree. C, while the latter is strongly stirred. The concentration in alcohol is preferably maintained at at least 50% in the second solution during the whole pouring process which should be effected with at least a slight excess of oxalic acid. The particles obtained may be treated for the preparation of solid solutions of oxides of iron and of the divalent metal or metals for the manufacture of magnetic tapes and the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.