RU2003107342A

RU2003107342A - METHOD FOR PRODUCING IRON OXIDES

Info

Publication number: RU2003107342A
Application number: RU2003107342/15A
Authority: RU
Inventors: Эстерино Конка; Карло Рубини; Гвидо Петрини
Original assignee: Зюд Кеми Мт С.Р.Л.
Priority date: 2002-03-18
Filing date: 2003-03-17
Publication date: 2004-09-10

Claims

1. A method of producing high purity iron oxides, comprising the following stages, carried out sequentially or simultaneously: a) the interaction of metallic iron in the form of microspherical particles having an average diameter of not more than 250 microns, or in the form of scrap or scraps, the sizes of which are such that their area per kg of iron and per liter of the reaction medium is more than 0.01 m ² , with a stirred aqueous solution of a carboxylic acid containing one or more carboxylic groups with pKa from 0.5 to 6 at ambient temperature relative to vodka carboxyl, capable of decomposing upon heating in air at temperatures from 200 to 350 ° C into carbon dioxide and water, and also to form iron (II) salts, soluble in an aqueous solution under the conditions of interaction, while the ratio between moles of carboxylic acid and g- iron atoms is from 0.03 to 1.5, the mass ratio of water / iron is from 1 to 20, the interaction temperature is from 0 to 100 ° C, and the microspherical particles are kept in suspension by stirring; b) oxidation to iron (III) carboxylate of iron (II) carboxylate obtained in stage a), an oxidizing agent selected from oxygen, an oxygen-containing gaseous mixture, hydrogen peroxide, ozone, organic peroxides and hydroperoxides, and used in excess relative to the stoichiometric amount salts of iron (II), oxidized to a salt of iron (III).

2. The method according to claim 1, in which the interaction temperature is from 5 to 70 ° C, and the molar ratio between carboxylic acid and g-iron atoms is from 0.05 to 0.8.

3. The method according to claim 1 or 2, in which oxygen or hydrogen peroxide is used as an oxidizing agent.

4. The method according to any of the preceding claims 1, 2 or 3, in which the particles of microspheroidal iron have an average diameter of less than 200 microns.

5. The method according to any one of claims 1 to 4, in which the carbon content in iron is less than 0.15 wt.%, And the content of alloying elements is less than 0.3 wt.%

6. A method of producing high purity iron oxides, comprising oxidizing with an oxidizing agent selected from oxygen, oxygen-containing gaseous mixtures, hydrogen peroxide, ozone, organic peroxides and hydroperoxides, used in excess relative to the stoichiometric amount of iron oxidized from an iron (II) ion to an ion iron (III), a pre-prepared carboxylate of iron (II) carboxylic acid, the pKa of the first carboxyl of which is from 0.5 to 6 and which can decompose upon heating from 200 to 350 ° C into CO ₂ and H ₂ O, or mixtures indicated a carboxylate with a carboxylic acid as described above, wherein the aqueous carboxylate solution is reacted with iron in the form of microspherical particles with an average diameter of less than 250 microns, or with iron turning chips or scraps having such dimensions that their surface area per kg of iron and per liter the solution is more than 0.01 m ² , and the molar ratio of the anion present in salt and acid to g-iron atoms is from 0.03 to 1.5, the mass ratio of water / iron is from 1 to 20, the interaction temperature I ranges from 0 to 100 ° C, and the microspherical iron is kept in suspension by stirring.

7. FeOOH oxides having a specific surface area of from 1 to 300 m ² / g; magemite (Fe ₂ O ₃ ) having a specific surface area of 1-15 m ² / g, while these oxides are free from alkaline and / or alkaline earth ions and / or ammonium ions, as well as sulfate and / or chloride anions.

8. Pigments obtained from iron oxides according to claim 7.

9. Catalysts containing iron oxides according to claim 7 or obtained from oxides according to claim 7.