GB2060590A - Process for producing hydrated iron oxide - Google Patents
Process for producing hydrated iron oxide Download PDFInfo
- Publication number
- GB2060590A GB2060590A GB8031810A GB8031810A GB2060590A GB 2060590 A GB2060590 A GB 2060590A GB 8031810 A GB8031810 A GB 8031810A GB 8031810 A GB8031810 A GB 8031810A GB 2060590 A GB2060590 A GB 2060590A
- Authority
- GB
- United Kingdom
- Prior art keywords
- goethite
- treatment
- suspension
- solution
- alkaline suspension
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims abstract description 21
- 238000000034 method Methods 0.000 title claims description 29
- 239000000725 suspension Substances 0.000 claims abstract description 38
- 229910052598 goethite Inorganic materials 0.000 claims abstract description 30
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 claims abstract description 30
- 230000032683 aging Effects 0.000 claims abstract description 19
- 239000007864 aqueous solution Substances 0.000 claims abstract description 14
- 239000000243 solution Substances 0.000 claims abstract description 14
- 238000010438 heat treatment Methods 0.000 claims abstract description 12
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910001447 ferric ion Inorganic materials 0.000 claims abstract description 3
- 238000001914 filtration Methods 0.000 claims description 5
- 238000000926 separation method Methods 0.000 claims description 4
- 235000013980 iron oxide Nutrition 0.000 claims 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 claims 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 18
- 239000002585 base Substances 0.000 description 17
- 239000012535 impurity Substances 0.000 description 9
- 239000000843 powder Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 5
- 229910021641 deionized water Inorganic materials 0.000 description 5
- 238000006386 neutralization reaction Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- -1 ferrous compound Chemical class 0.000 description 3
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000006247 magnetic powder Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 229910001860 alkaline earth metal hydroxide Inorganic materials 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
- G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
- G11B5/706—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material
- G11B5/70626—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances
- G11B5/70642—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the composition of the magnetic material containing non-metallic substances iron oxides
- G11B5/70678—Ferrites
- G11B5/70684—Ferro-ferrioxydes
- G11B5/70689—Magnetite
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/06—Ferric oxide [Fe2O3]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G49/00—Compounds of iron
- C01G49/02—Oxides; Hydroxides
- C01G49/08—Ferroso-ferric oxide [Fe3O4]
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/12—Surface area
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/42—Magnetic properties
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Iron (AREA)
Abstract
A hydrated iron oxide comprising goethite as a main component is produced by treatment of an alkaline suspension obtained by mixing a base with an aqueous solution comprising ferric ions as a main component. A part of the solution is separated from said alkaline suspension, further aqueous base solution is added to the residue and alkaline suspension thus formed is subjected to an ageing treatment and/or a heat-treatment.
Description
SPECIFICATION
Process for producing hydrated iron oxide
The present invention relates to a hydrated iron oxide comprising goethite as a main component.
Recently, goethite has been used in various fields such as in pigment as a source of ferrite and as a source of magnetic powders for magnetic recording media. The demand for goethite has therefore increased.
Various processes for producing a hydrated iron oxide comprising goethite as a main component by mass production methods and at economical cost have been proposed, in view of the increase in demand for goethite.
Goethite has been produced by adding an aqueous solution of a base at a concentration of 10 to 50% of the base sufficient for neutralization, to an aqueous solution of a ferrous compound such as ferrous sulfate to give a pH of about 4 and then bubbling air into the solution. The resulting goethite has not been of satisfactory quality because of the incorporation of relatively large amounts of impurities and the uneven configuration of particles which make the product unsatisfactory as a source of magnetic recording media.
A process for producing goethite by oxidation under alkaline conditions instead of under acidic conditions has been proposed to overcome the above-mentioned disadvantages, and goethite of high purity with an even configuration of particles has been obtained in this way. The process, however, has disadvantages. Since the oxidation is carried out under alkaline conditions, it requires about twice the amount of base required for
neutralization of the ferrous compound. The use of a large amount of a base is disadvantageous from the point of increased production costs and the difficulty of water washing to remove the base after the reaction. There is also the problem that sodium hydroxide the base most commonly used, is still produced in large quantities by the mercury process which is a source of pollution.
It has been proposed to produce goethite from a ferric compound instead of the ferrous compound as the starting material In the latter process, a base is added to an aqueous solution of the ferric compound in an amount slightly in excess (by a few %) of the amount required for neutralization and the mixture is treated by ageing for a long period or treated in an autoclave at a
high temperature such as 150 to 200cm for about
1 hour to obtain goethite. The resulting goethite is of high purity with an even configuration of
particles and thus of high quality. It takes about
100 to 200 hours to obtain goethite of good industrial quality by the ageing treatment. The
productivity is remarkably low. On the other hand, treatment in an autoclave is not suitable for economical industrial mass production.
The latter process for producing goethite using the ferric compound as the starting material has
not therefore been satisfactory.
As discussed, the conventional processes for producing a hydrated iron oxide comprising goethite as a main component have not been satisfactory as industrial processes, and accordingly, some improvement has been required.
The inventor has studied processes for producing a high quality hydrated iron oxide comprising goethite as a main component by mass production and at economical cost, from the viewpoints of product source saving, pollution, energy saving, productivity and product quality. As a result, the inventor has concluded that certain process using the ferric compound as the starting material would be optimum for producing a hydrated iron oxide. In order to overcome the above-mentioned disadvantages, the inventor has concentrated on processes for producing goethite relatively quickly, without an autoclave and with only a modest consumption of base.
It is an object of the present invention to produce a hydrated iron oxide comprising goethite as a main component which is of high quality by a mass production process, rapidly and without an autoclave, and reducing the amount of base used for neutralization.
The present invention provides a process for producing a hydrated iron oxide comprising goethite as a main component, which comprises mixing a base with an aqueous solution comprising ferric ions as a main component to give an alkaline suspension, separating a part of the solution from said alkaline suspension adding further aqueous base solution to the residue of the alkaline suspension and subjecting the resulting alkaline suspension to an ageing treatment and/or a heat-treatment.
The reason why a long time such as 100 to 200 hours is required for the ageing treatment in the conventional process has been studied. It has been found that when a base is added to an aqueous solution of a ferric salt, impurities such as by-products of the reaction or impurities from the starting materials are dissolved in the water. Such water-soluble impurities adversely affect the ageing treatment or the heat-treatment. It is not clear which of these water insoluble impurities cause these adverse effects, but it has been confirmed that the ageing or the conversion by heat-treatment proceed much more quickly if the water soluble impurities are separated. The ageing time can be remarkably shortened.
Goethite could not be obtained merely by heating at about 1 000C the alkaline suspension obtained by mixing a base with an aqueous solution of a ferric salt, without any ageing treatment, but it can be obtained by heating at about 1 000C the alkaline suspension if the water insoluble impurities are separated from the alkaline suspension.
In accordance with the process of the present invention, the alkaline suspension is prepared by mixing a base with an aqueous solution comprising a ferric salt such as ferric chloride as a main component. The amount of the base is preferably slightly in excess, for example by 1 to 10% of the amount required for neutralization. The alkaline suspension has a reddish brown color. The base usually used is sodium hydroxide but other alkali or alkaline earth metal hydroxides and carbonates such as potassium hydroxide and calcium hydroxide can also be used.
In order to separate at least part of the water soluble impurities in solution from the reddish brown suspension, part of the solution is separated from the suspension, preferably by filtration or a centrifugal separation. An aqueous solution of a base is added to the residue obtained after the separation to prepare a new alkaline suspension, which need only be slightly alkaline.
The separation of the solution can be repeated, if necessary. The new alkaline suspension can be treated by ageing at a desired temperature, for example at 20 to 700C for 9 to 30 hours the color of the suspension is changed from reddish brown to yellow and the formation of goethite is completed.
In an alternative process, the new alkaline suspension can be subjected to a heat-treatment for example at 70 to 1 000C, suitably 900 C, without any ageing treatment whereby the formation of goethite is completed in a shorter time.
It is preferable to subject the new alkaline suspension to an ageing treatment and then to a heat-treatment at a higher temperature.
The precipitate can then be separated by filtration, washed with water and dried to obtain fine acicular goethite powder.
In the process of the present invention which comprises separating the water soluble impurities before the ageing or heat-treating step, the conversion into goethite proceeds easily to give goethite of high quality in a shorter ageing time or in a shorter heat-treating time at higher temperature in comparison with conventional processes. The industrial advantages of the process of the present invention are remarkable.
The present invention will be illustrated by the following examples and references which are provided for purposes of illustration only and are not to be construed as limiting the present invention.
EXAMPLE 1
Into a solution of 54 g. of ferric chloride (FeCI3 . 6H2O) in 500 ml. of a deionized water, a solution of 25 g. of sodium hydroxide (purity of 95%) in 500 ml. of deionized water was added with stirring. The resulting reddish brown suspension was filtered to separate about 80% of water soluble components. Into the residual suspension, 700 ml. of a deionized water and 50 ml. of 2N-aqueous solution of sodium hydroxide were added to form a suspension having pH of 12.7.
The alkaline suspension was heated to 900C during about 1 hour and maintained at 900C i 20for 8 hours. The color of the suspension was changed from reddish brown through brown and finally to yellow.
The precipitate was washed with water and filtered and dried to obtain a yellow powder.
According to the X-ray diffraction, it was confirmed that the yellow powder is mainly goethite. According to the measurement by the
BET method, the powder had a specific surface area of 54.4 m2/g.
The yellow powder was dehydrated at 6000C and reduced at 4000C in an atmosphere of nitrogen gas containing ethanol to obtain magnetite. The magnetite had magnetic characteristics of a coercive force of 423 Oe and a saturation magnetic moment per unit weight of 83.5 emu/g. The magnetite can be used as a magnetic powder for a magnetic recording medium.
Reference 1
In accordance with the process of Example 1, the alkaline suspension was prepared and then 50 ml. of 2N-aqueous solution of sodium hydroxide was added without separating the water soluble components by a filtration and then, the suspension was treated by the heat-treatment of Example 1. The color of the suspension was changed from reddish brown to bright brown, but was not changed to yellow as Example 1.
EXAMPLE 2
Into a solution of 32 g. of sodium hydroxide (purity of 95%) in 350 ml. of deionized water, 90 ml. of 35% aqueous solution of ferric chloride was added with stirring to prepare a reddish brown suspension. The suspension was filtered to separate most of water soluble components and then 400 ml. of a deionized water and 10 ml. of 6N-aqueous solution of sodium hydroxide were added to form a suspension having pH of 12.6.
The suspension wastreated by an ageing treatment for 1 5 hours at 600 C, whereby the color of the suspension was changed to yellow. The yellow powder was separated by the process of
Example 1. It was confirmed that the yellow powder was goethite.
A magnetite produced from the goethite powder by the process of Example 1 had magnetic characteristics of a coercive force of 4380 Oe and a saturation magnetic moment per unit weight of 81.5 emu/g.
Reference 2
A reddish brown suspension obtained by the process of Example 2 except removing the water soluble components by the filtration, was treated by the ageing treatment at the same temperature.
The color of the suspension was changed to yellow after 100 hours.
Claims (6)
1. A process for producing a hydrated iron oxides comprising goethite as a main component, which comprises mixing a base with an aqueous solution comprising ferric ions as a main component to give an alkaline suspension, separating a part of the solution from said alkaline suspension, adding further aqueous base solution to the residue of the alkaline suspension and subjecting the resulting alkaline suspension to an ageing treatment and/or a heat-treatment.
2. A process according to Claim 1 wherein said solution is separated by filtration or a centrifugal separation.
3. A process according to Claim 1 or Claim 2 wherein said ageing treatment is carried out at 20 to 700C.
4. A process according to any preceding Claim wherein said heat-treatment is carried out at 70 to 1000C.
5. A process according to any preceding Claim wherein said ageing treatment is carried out and then said heat-treatment is carried out.
6. A process according to Claim 1 substantially as herein described with reference to any one of the Examples.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12635479A JPS5650121A (en) | 1979-10-02 | 1979-10-02 | Manufacture of iron oxide hydrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2060590A true GB2060590A (en) | 1981-05-07 |
| GB2060590B GB2060590B (en) | 1983-04-07 |
Family
ID=14933099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8031810A Expired GB2060590B (en) | 1979-10-02 | 1980-10-02 | Process for producing hydrated iron oxide |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5650121A (en) |
| DE (1) | DE3037346A1 (en) |
| GB (1) | GB2060590B (en) |
| NL (1) | NL8005433A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0076462B2 (en) * | 1981-10-01 | 1991-01-16 | Agency Of Industrial Science And Technology | Method of production of magnetic particles |
-
1979
- 1979-10-02 JP JP12635479A patent/JPS5650121A/en active Pending
-
1980
- 1980-10-01 NL NL8005433A patent/NL8005433A/en not_active Application Discontinuation
- 1980-10-02 GB GB8031810A patent/GB2060590B/en not_active Expired
- 1980-10-02 DE DE19803037346 patent/DE3037346A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE3037346A1 (en) | 1981-04-23 |
| JPS5650121A (en) | 1981-05-07 |
| NL8005433A (en) | 1981-04-06 |
| GB2060590B (en) | 1983-04-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19941002 |