CN1066564C - Method for preparing super fine barium ferrite powder - Google Patents
Method for preparing super fine barium ferrite powder Download PDFInfo
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- CN1066564C CN1066564C CN97112639A CN97112639A CN1066564C CN 1066564 C CN1066564 C CN 1066564C CN 97112639 A CN97112639 A CN 97112639A CN 97112639 A CN97112639 A CN 97112639A CN 1066564 C CN1066564 C CN 1066564C
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- barium
- barium ferrite
- ferrite powder
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Abstract
The present invention relates to a method for preparing super-fine barium ferrite powder, which comprises the following steps: (a). uniformly mixing the quantitative salt solution of barium and ferrite, dropping sodium hydroxide solution into the salt solution, controlling the pH valve of the end point at 11.0 to 12.0, and continuously mixing and ageing to obtain barium-ferrite aquogel; (b). filtering and washing the barium-ferrite aquogel; (c). carrying out gel-water exchange on a filter cake by low-carbon organic alcohol so as to obtain alcogel; (d). putting the alcogel into an autoclave, and adding the low-carbon organic alcohol as an extraction agent; sweeping the autoclave by nitrogen, and heating the autoclave in a sealing mode; deprivating solvents in the range higher than the critical temperature of 10 to 50 DEG C and the critical pressure of 10 to 30 atm of the organic alcohol so as to obtain aerogel; (e). sintering the aerogel powder for three to four hours at the temperature of 700 to 800 DEG C in the air, and quenching the sintered aerogel powder so as to obtain the brown super-fine barium ferrite powder. The present invention has the characteristics of easy operation, simple processes, energy saving, etc.
Description
The invention belongs to the preparation of magnetic material, relate generally to a kind of preparation method of super fine barium ferrite powder.
Barium ferrite is not only a kind of permanent magnetic material that is widely used in daily production and sphere of life, but also is a kind of perpendicular magnetic recording medium with potential using value.In the past, what people mainly adopted is that ceramic sintering process obtains barium ferrite.This method at first will be mixed solid material iron oxide and brium carbonate, then through grinding pre-burning, moulding, last sintering etc.But big because the barium ferrite powder that adopts this method to obtain has a particle, shortcoming such as particle size distribution is inhomogeneous, and the final character of particle is subjected to destroying significantly, the sintering temperature height and can not adapt to the needs of development in science and technology gradually.Along with nanometer technology is in the infiltration in material field in recent years, researchers begin to be conceived to the development and application of nano material, and the research of nano magnetic material has also obtained corresponding development.Up to the present, developed the number of chemical method about the preparation people of super fine barium ferrite powder, as coprecipitation, hydro thermal method, sol-gel process or the like.Said method generally will pass through following step: batching-precipitation (one-tenth glue)-washing-drying-sintering etc.In above-mentioned steps, dry and sintering two goes on foot relatively more crucial, and they determine gained particle performance effect.A common big shortcoming that exists is in above method, inevitably interparticle gathering and sintering will take place at dry and sintering in two steps, and this has just caused losing of the original partial properties of gained particle.In addition, also have glass crystallization method and spray pyrolysis etc. in the industrial method that has obtained large-scale production, but their shortcoming be the coercive force of gained particle and theoretical value deviation more too.
In order to overcome above-mentioned shortcoming, people have developed supercritical fluid drying, as Chinese patent " a kind of γ-Fe
2O
3The preparation method of magnetic " (CN1108424A) and " superfine tin dioxide powder and its production and use " (CN1121047A), this method deficiency is to be mainly used to prepare single oxide.
Chinese patent CN1108425A " super-fine magnetic powder and manufacture method thereof " discloses a kind of cobalt γ-Fe that mixes
2O
3The manufacturing technology of magnetic, but this kind material is mainly used in horizontal magnetic recording, can not adapt to the needs of perpendicular magnetic recording.
The purpose of this invention is to provide a kind of method for preparing barium ferrite composite oxides superfines with supercritical fluid drying.
The preparation method of barium ferrite composite oxides ultrafine particle of the present invention comprises the steps:
(a) with the salting liquid of barium, iron by (the Ba/Fe mol ratio is 1: 10-1: 12) mix, splash into sodium hydroxide solution, its endpoint pH is controlled at 11.0-12.0, continues to stir, aging, obtains barium-molten iron gel;
(b) with barium-molten iron gel filtration, washing;
(c) with the organic alcohol of low-carbon (LC) filter cake is carried out pure water exchange then, obtain alcogel;
(d) alcogel is placed in the autoclave, add the organic alcohol of low-carbon (LC) as extractant, purge with nitrogen, heated sealed is carried out solvent removal in the scope that is higher than organic pure critical temperature 10-50 ℃ and critical pressure 10-30atm, obtain aerogel powder at last.
(e) with aerogel powder in 700-800 ℃ scope, in the air sintering 3-8 hour, quench, obtain the barium ferrite superfines of brown.
Aforesaid low-carbon alcohols is methyl alcohol, ethanol, propyl alcohol preferably.
Aforesaid barium salt is barium nitrate, barium chloride preferably.
Aforesaid molysite is ferric nitrate, iron chloride preferably.
Aforesaid sintering time preferably 3-4 hour.
Preparation process of the present invention, key are to have utilized under the supercriticality to remove solvent, can avoid the characteristics of the particle accumulation that interparticle surface tension brings, and have following advantage:
(1) particle diameter is little, even particle size distribution
(2) particle is active high
(3) magnetic property of particle more approaches theoretical value
(4) easy to operate, flow process is simple, saves the energy.
Most preferred embodiment of the present invention is as follows:
Embodiment 1
By the Ba/Fe mol ratio is 1: 12.0, with 48.5g Fe (NO
3)
39H
2O is dissolved in the deionized water of 120ml, with 2.61g Ba (NO
3)
2Be dissolved in the 80ml deionized water, after mixing, drip NaOH solution, dripping speed is 2-3ml/ minute.The pH value of the hierarchy of control is 12.0.Continue to stir half an hour, wear out after 2 hours, use deionized water wash, filter, divide with the 400ml absolute ethyl alcohol again and carry out pure water exchange for 4 times.Obtain alcogel.Alcogel is moved in the autoclave of 0.5 liter, add the 320ml absolute ethyl alcohol.Purged 10 minutes with nitrogen behind the first-class kettle cover, airtight, heating.When temperature in the kettle and pressure reach critical point (243 ℃, 6.3MPa) after, continue to be heated to temperature and pressure and be respectively 260 ℃, 8.0MPa constant 30 minutes, discharges the ethanol in the still, lentamente to normal pressure under 260 ℃ temperature.Purge with nitrogen at last, naturally cool to room temperature, open the still taking-up and promptly get aeroge.With aerogel powder 750 ℃ of roasting temperatures 3.5 hours, the barium ferrite superfines of brown, its magnetic property is as follows: HCJ is 62000Oe, specific saturation magnetization is 51emu/g, squareness ratio is 0.60.
Embodiment 2
Step is with embodiment 1, and 800 ℃ of roasting temperatures 200 minutes, the magnetic property of the barium ferrite powder that obtains after quenching in air is as follows: HCJ was 6014.5Oe, and specific saturation magnetization is 51.62emu/g, and squareness ratio is 0.58 with aerogel powder.
Embodiment 3
Step is with embodiment 1, and changing system pH is 11.0, and the magnetic property of gained powder is as follows: HCJ is 6026.5Oe, and specific saturation magnetization is 50.49emu/g, and squareness ratio is 0.59.
Embodiment 4
Step is with embodiment 1, and the temperature when changing supercritical fluid drying is 300 ℃, and the magnetic property of gained powder is: HCJ is 5995.5Oe, and specific saturation magnetization is 59.37emu/g, and squareness ratio is 0.55.
Embodiment 5
Step is with embodiment 1, and the iron barium that changes batching is than Ba/Fe=1: 11, and the magnetic property of gained powder is: HCJ is 5525.2Oe, and specific saturation magnetization is 58.36emu/g, and squareness ratio is 0.52.
Embodiment 6
Step is with embodiment 1, and the iron barium that changes batching is than Ba/Fe=1: 10.5, and the magnetic property of gained powder is: HCJ is 5301.0Oe, and specific saturation magnetization is 53.98emu/g, and squareness ratio is 0.52.
Claims (5)
1. the preparation method of a super fine barium ferrite powder is characterized in that comprising the steps:
(a) with the salting liquid of barium, iron by Ba/Fe than 1: 10.0-1: 12.0 mix, and splash into hydrogen-oxygen
Change sodium solution, its endpoint pH is controlled at 11.0-12.0, continues to stir, and is aging, obtains barium-molten iron
Gel;
(b) with barium-molten iron gel filtration, washing;
(c) with the organic alcohol of low-carbon (LC) filter cake is carried out pure water exchange then, obtain alcogel;
(d) alcogel is placed in the autoclave, add the organic alcohol of low-carbon (LC), blow with nitrogen as extractant
Sweep, heated sealed is being higher than the organic pure critical temperature 10-50 of low-carbon (LC) ℃ with critical pressure 10-30atm's
Carry out solvent removal in the scope, obtain aeroge at last.
(e) with aerogel powder in 700-800 ℃ scope, in the air sintering 3-8 hour, quench,
Barium ferrite superfines to brown.
2. the preparation method of super fine barium ferrite powder according to claim 1 is characterized in that described
Low-carbon alcohols be methyl alcohol, ethanol, propyl alcohol.
3. the preparation method of super fine barium ferrite powder according to claim 1 is characterized in that described
Barium salt be barium nitrate, barium chloride.
4. the preparation method of super fine barium ferrite powder according to claim 1 is characterized in that described
Molysite be ferric nitrate, iron chloride.
5. the preparation method of super fine barium ferrite powder according to claim 1 is characterized in that described
Sintering time be 3-4 hour.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97112639A CN1066564C (en) | 1997-06-14 | 1997-06-14 | Method for preparing super fine barium ferrite powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN97112639A CN1066564C (en) | 1997-06-14 | 1997-06-14 | Method for preparing super fine barium ferrite powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1202707A CN1202707A (en) | 1998-12-23 |
| CN1066564C true CN1066564C (en) | 2001-05-30 |
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ID=5172407
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| Application Number | Title | Priority Date | Filing Date |
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| CN97112639A Expired - Fee Related CN1066564C (en) | 1997-06-14 | 1997-06-14 | Method for preparing super fine barium ferrite powder |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100484899C (en) * | 2004-01-19 | 2009-05-06 | 南京大学 | Ion-exchange process for preparation of super-thin sheet-shaped M-type barium ferrite particulates |
| CN1308104C (en) * | 2005-02-07 | 2007-04-04 | 武汉理工大学 | Process for synthesizing barium ferrite micro powder by self combustion method |
| CN100406406C (en) * | 2005-07-28 | 2008-07-30 | 上海交通大学 | Method for preparing M-type barium ferrite magnetic powder |
| CN101559982B (en) * | 2009-05-27 | 2011-08-31 | 南京工业大学 | Method for synthesizing hexagonal barium ferrite nanocrystalline in one step by microwave-assisted sol-gel self-combustion method |
| CN102260072A (en) * | 2011-06-13 | 2011-11-30 | 中国地质大学（武汉） | Method for synthesizing high-performance barium ferrite by using molten salt as flux and reaction medium |
| CN108585798B (en) * | 2018-05-09 | 2022-02-18 | 安徽弘徽科技有限公司 | Nano porous alumina aerogel ceramic pellet and preparation method thereof |
| CN110735362B (en) * | 2018-10-18 | 2022-01-25 | 嘉兴学院 | Preparation method of conductive paper for electromagnetic shielding protection card |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06287020A (en) * | 1993-03-31 | 1994-10-11 | Nittetsu Mining Co Ltd | Production of ferrite colloid |
| CN1108425A (en) * | 1994-03-07 | 1995-09-13 | 中国科学院山西煤炭化学研究所 | Super-fine magnetic powder and its prepn. method |
-
1997
- 1997-06-14 CN CN97112639A patent/CN1066564C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06287020A (en) * | 1993-03-31 | 1994-10-11 | Nittetsu Mining Co Ltd | Production of ferrite colloid |
| CN1108425A (en) * | 1994-03-07 | 1995-09-13 | 中国科学院山西煤炭化学研究所 | Super-fine magnetic powder and its prepn. method |
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| CN1202707A (en) | 1998-12-23 |
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