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Obtaining Fe(3)O(4) of High Magnetic Moment for Magnetic Inks

IP.com Disclosure Number: IPCOM000082386D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gardineer, BA: AUTHOR [+2]

Abstract

Described is a method of Fe O preparation which requires a reduced number of steps, which uses only one iron reagent and which, therefore, can be more easily adapted to scale-up techniques for the fabrication of large amounts of magnetite for industrial ink production. Furthermore, this technique has consistently yielded magnetite (Fe(3)O(4)) of magnetic moment close to the theoretical of pure Fe(3)O(4).

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Obtaining Fe(3)O(4) of High Magnetic Moment for Magnetic Inks

Described is a method of Fe O preparation which requires a reduced number of steps, which uses only one iron reagent and which, therefore, can be more easily adapted to scale-up techniques for the fabrication of large amounts of magnetite for industrial ink production. Furthermore, this technique has consistently yielded magnetite (Fe(3)O(4)) of magnetic moment close to the theoretical of pure Fe(3)O(4).

In the present technique, it is shown that if ferrous hydroxide (as the only starting iron reagent) can be oxidized to ferric hydroxide, as soon as the latter is formed it will react with the ferrous hydroxide present to give Fe(3)O(4). The reaction will proceed until all the Fe(OH)(2) is converted into magnetite.

The technique is implemented as follows. An amount of ferrous chloride is dissolved in water, and sodium hydroxide is added adjusting the pH to about 9. This precipitates finely divided Fe(OH)(2). The mixture is taken to about 60 degrees C, thoroughly stirred by bubbling a stream of air until all the precipitated ferrous hydroxide has been converted to Fe(3)O(4).

The mechnnism of the reaction can be interpreted as follows: A. First, ferrous hydroxide is oxidized by air in the water solution to give Fe(OH)(3). B. Fe(OH)(3) formed reacts immediately with the Fe(OH)(2) present to give Fe(3)O(4). A. 2Fe(OH)(2) + 1/2O(2) + H(2)O = 2Fe(OH)(3) B. Fe(OH)(2) + 2Fe(OH)(3) = Fe(3)O(4) + 4H(2)O Net react...