Claims
- 1. A method of improving the magnetic properties of isometric magnetic iron oxides comprising reacting acicular .gamma.-FeOOH in an aqueous alkaline suspension with Co(II) ions, Ti(IV) ions and Fe(II) ions under inert gas at a pH higher than 8 and at from 35.degree. C. to the boiling point of the suspension to produce isometric cobalt- and titanium-containing magnetic iron oxide which contains from 2 to 8% by weight of cobalt(II) ions and from 0.5 to 6% by weight of titanium(IV) ions.
- 2. The method of claim 1 wherein the acicular .gamma.-FeOOH is reacted in aqueous alkaline suspension with Co(II) ions, Ti(IV) ions and Fe(II) ions under inert gas at a pH higher than 8 and at from 35.degree. C. to the boiling point of the suspension, and the resulting product is subsequently at least partially oxidized with oxidizing gases at 120.degree.-450.degree. C.
- 3. The method of claim 1 wherein said acicular .gamma.-FeOOH is Co(II)- and Ti(IV)-free .gamma.-FeOOH.
- 4. The method of claim 1 wherein said acicular .gamma.-FeOOH contains Co(II), Ti(IV) or mixture thereof.
- 5. A method of improving the magnetic properties of isometric magnetic iron oxides comprising precipitating iron(II) hydroxide from an Fe(II) salt solution with aqueous alkali, oxidizing the precipitated iron(II) hydroxide to form a suspension of .gamma.-FeOOH nuclei, blanketing the suspension with an inert gas atmosphere, adding Co(II) ions, Ti(IV) ions and a base to the suspension to precipitate Fe(II)ions as Fe(OH).sub.2 and reacting the .gamma.-FeOOH at a pH of more than 8 and at from 35.degree. C. to the boiling point of the suspension to produce isometric cobalt-and titanium-containing magnetic iron oxide which contains from 2 to 8% by weight of cobalt(II) ions and from 0.5 to 6% by weight of titanium(IV) ions.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3515517 |
Apr 1985 |
DEX |
|
Parent Case Info
This application is a continuation of application Ser. No. 856,959, filed on Apr. 29, 1986, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3912646 |
Leitner et al. |
Oct 1975 |
|
4115106 |
Snavely et al. |
Sep 1978 |
|
Foreign Referenced Citations (2)
Number |
Date |
Country |
50-37667 |
Apr 1975 |
JPX |
1092009 |
Nov 1967 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Hattori et al "Joint Intermag-MMM Conference" (Jul., 1979). |
Continuations (1)
|
Number |
Date |
Country |
Parent |
856959 |
Apr 1986 |
|