GB2059411A - Process for producing hydrated iron oxide - Google Patents
Process for producing hydrated iron oxide Download PDFInfo
- Publication number
- GB2059411A GB2059411A GB8031820A GB8031820A GB2059411A GB 2059411 A GB2059411 A GB 2059411A GB 8031820 A GB8031820 A GB 8031820A GB 8031820 A GB8031820 A GB 8031820A GB 2059411 A GB2059411 A GB 2059411A
- Authority
- GB
- United Kingdom
- Prior art keywords
- goethite
- treatment
- ageing
- suspension
- process according
- 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.)
- Withdrawn
Links
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims description 29
- 229910052598 goethite Inorganic materials 0.000 claims abstract description 37
- AEIXRCIKZIZYPM-UHFFFAOYSA-M hydroxy(oxo)iron Chemical compound [O][Fe]O AEIXRCIKZIZYPM-UHFFFAOYSA-M 0.000 claims abstract description 37
- 239000000725 suspension Substances 0.000 claims abstract description 31
- 230000032683 aging Effects 0.000 claims abstract description 28
- 238000011282 treatment Methods 0.000 claims abstract description 16
- 239000007864 aqueous solution Substances 0.000 claims abstract description 12
- 238000010438 heat treatment Methods 0.000 claims abstract description 11
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910001447 ferric ion Inorganic materials 0.000 claims abstract description 8
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 claims description 6
- 238000006386 neutralization reaction Methods 0.000 claims description 5
- 238000009835 boiling Methods 0.000 claims description 4
- 239000002585 base Substances 0.000 description 13
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 239000000843 powder Substances 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 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
- 150000003839 salts Chemical class 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
- 238000001914 filtration Methods 0.000 description 3
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 3
- 239000006247 magnetic powder Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 238000004438 BET method Methods 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000010348 incorporation Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000003679 aging 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
- 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
- 239000012535 impurity Substances 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
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 231100000989 no adverse effect Toxicity 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 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
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/60—Particles characterised by their size
- C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
-
- 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)
- Hard Magnetic Materials (AREA)
Abstract
A hydrated iron oxide comprising goethite as a main component is produced from an alkaline suspension obtained by mixing a base with an aqueous solution of a ferric ion as a main component. The alkaline suspension is subjected first to an ageing treatment e.g. at 20-70 DEG C for 3-20 hours and then to a heat- treatment at a temperature higher than the ageing temperature e.g. at 70-100 DEG C and under atmospheric pressure.
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 2000C 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.
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 containing ferric ions as a main component to form an alkaline suspension, subjecting the suspension to an ageing treatment and then subjecting the suspension at heat-treatment at a temperature higher than the ageing temperature under atmospheric pressure.
The present invention is based on the finding that goethite of high quality can be obtained in a relatively short time without an autoclave by improving the treatments of the alkaline suspension obtained by mixing a base with an aqueous solution of ferric ions.
In 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 a slight excess, for example 1 to 10% more than the amount required for neutralization. The alkaline suspension has a reddish brown color. A typical base is sodium hydroxide but other alkali or alkaline earth metal hydroxides and carbonates such as potassium hydroxide and calcium hydroxide may be used.
The alkaline suspension is treated to convert the hydrated iron oxide to goethite. In the conventional process, an ageing treatment of 100 to 200 hours is carried out. In the process of the present invention, when some effect has been achieved by ageing for a short time the treatment is changed to a heat-treatment so as to accelerate the reaction whereby goethite of high quality can be obtained. Moreover, it is an important advantage that the heat-treatment can be carried out under atmospheric pressure without any special equipment such as an autoclave. On the other hand, goethite of high quality could not be obtained without any ageing, using only the heattreatment.For example, yellow goethite of high quality could not be obtained without ageing, simply by a heat-treatment at 80 to 1 00cm. Thus, it is clear that the ageing treatment is a
indispensable step which cannot be eliminated if
goethite of high quality is required.
In the process of the present invention, the
alkaline suspension of a ferric salt is preferably
aged for a few hours possibly up to ten, fifteen or
even twenty hours. The conditions for ageing can
be the same as in conventional processes,
maintaining the alkaline suspension at 20 to 700C for 3 to 20 hours with mild stirring.
The alkaline suspension of a ferric salt has a
reddish brown color. The color is gradually
changed in the ageing. In the conventional process of ageing for 100 to 200 hours, the color changed to yellow to complete the conversion into goethite. However, in the process of the invention, the ageing treatment is changed to the heattreatment at higher temperature after a certain degree of ageing whereby goethite of excellent quality can be obtained. The stage at which the
ageing treatment is stopped in favour of the heattreatment is preferably when the color of the
alkaline suspension changes from reddish brown to brown. The period from the beginning of the ageing treatment to this color change is usually
less than 20 hours at normal ageing temperatures, though it depends upon the precise ageing temperature.For example, it is 16 hours at an ageing temperature of 300C and 4 hours at an ageing temperature of 600 C. In any case, the ageing effect required for the conversion into goethite reaches a desired level at a relatively early stage after beginning of the ageing treatment. Even though the temperature is raised after reaching such a stage, no adverse effect is found. The alkaline suspension after the ageing treatment is usually heated to 700C or more preferably up to 1000C or the boiling temperature of the mixture, and maintained for 5 to 10 hours.
The conversion into goethite occurs at high speed.
The conversion is completed when the color of the alkaline suspension is changed to yellow.
The precipitate can be separated by filtration, washed with water and dried to obtain fine acicular goethite powder.
When zinc ions are incorporated in the alkaline suspension of the ferric salt, the acicular ratio of the resulting goethite is improved and the characteristics of the magnetic powder for a
magnetic recording medium are improved. The
amount of Zn2+ incorporated in the alkaline
suspension is a ratio of Zn2+/Fe3+ of about 1 to
3%.
The present invention will be illustrated by the
following examples which are provided for
purposes of illustration only and are not to be
construed as limiting the present invention.
EXAMPLE 1
In 600 ml of deionized water, 25 g of sodium hydroxide (purity of 95%) was dissolved and 60 ml of 35% aqueous solution of ferric chloride was added with stirring to prepare a reddish brown suspension. The suspension was aged at 300C i 30C for 16 hours. The color of the suspension was changed from reddish brown to yellowish brown. At this time, the suspension was heated and kept boiling for 8 hours. The color of the suspension was changed to yellow. The precipitate was separated by filtration, washed with water and dried to give a yellow powder. By
X-ray diffraction, it was confirmed that the powder was goethite.According to observation under an electron microscope, it was confirmed that the powder is an acicular crystal having an average length of about 0.68 #. According to the measurement by the BET method, the powder had a specific surface area of 63.4 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 41 5 Oe and a saturation magnetic moment per unit weight of 82.3 emu/g. The magnetite can be used as a magnetic powder for a magnetic recording medium.
EXAMPLE 2
Into 500 ml of a deionized water, 27.0 g of ferric chloride (FeCI3 - 6H20) was dissolved and 2 ml of 1 Mol solution of zinc chloride was added.
A ratio of Zn2+/Fe3+ was about 2% by weight. Into the solution, 2N-aqueous solution of sodium hydroxide was added with stirring to obtain a reddish brown suspension having pH of 12.5.
The suspension was aged at 600C for 4 hours with a mantle heater whereby the suspension was changed into brown color. The suspension was heated and maintained in the boiling condition for 8 hours to obtain a yellowish brown suspension.
rhe precipitate was separated by a filtration and washed with water and dried to obtain a powder.
According to the X-ray diffraction, it was confirmed that the powder is goethite. The goethite powder is an acicular crystal having an average length of 0.54 #u and an improved acicular ratio resulted by the incorporation of zinc ion.
According to the measurement by the BET method, the specific surface area of the goethite powder was 84.7 m2/g.
A magnetite produced from the goethite powder by the process of Example 1 had magnetic characteristics of a coercive force of 435 Oe and a saturation magnetic moment per unit weight of 81.2 emu/g.
Claims (8)
1. A process for producing a hydrated iron oxide comprising goethite as a main component which comprises mixing a base with an aqueous solution containing ferric ions as a main component to form an alkaline suspension, subjecting the suspension to an ageing treatment and then subjecting the suspension to a heat-treatment at a temperature higher than the ageing temperature under atmospheric pressure.
2. A process according to Claim 1 wherein said ageing treatment is carried out at least until the color of said alkaline suspension changes from reddish brown to brown.
3. A process according to Claim 1 or Claim 2 wherein said ageing treatment is carried out at 20 to 700C for 3 to 20 hours.
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 one of Claims 1 to 3 wherein said heat-treatment is carried out by boiling for 5 to 10 hours.
6. A process according to any preceding Claim wherein said base is added in an amount slightly in excess of that required for neutralization of said aqueous solution of ferric ions.
7. A process according to any preceding claim wherein zinc ions are incorporated in said aqueous solution of ferric ions.
8. 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 |
|---|---|---|---|
| JP12635379A JPS5650120A (en) | 1979-10-02 | 1979-10-02 | Manufacture of iron oxide hydrate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2059411A true GB2059411A (en) | 1981-04-23 |
Family
ID=14933072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8031820A Withdrawn GB2059411A (en) | 1979-10-02 | 1980-10-02 | Process for producing hydrated iron oxide |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5650120A (en) |
| DE (1) | DE3037345A1 (en) |
| GB (1) | GB2059411A (en) |
| NL (1) | NL8005435A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4459276A (en) * | 1981-09-17 | 1984-07-10 | Agency Of Industrial Science & Technology | Yellow iron oxide pigment and method for manufacture thereof |
| JPH0429120Y2 (en) * | 1987-03-28 | 1992-07-15 |
-
1979
- 1979-10-02 JP JP12635379A patent/JPS5650120A/en active Granted
-
1980
- 1980-10-01 NL NL8005435A patent/NL8005435A/en not_active Application Discontinuation
- 1980-10-02 GB GB8031820A patent/GB2059411A/en not_active Withdrawn
- 1980-10-02 DE DE19803037345 patent/DE3037345A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| DE3037345A1 (en) | 1981-04-23 |
| NL8005435A (en) | 1981-04-06 |
| JPS6251896B2 (en) | 1987-11-02 |
| JPS5650120A (en) | 1981-05-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |