JPS63225533A - Production of barium ferrite powder - Google Patents
Production of barium ferrite powderInfo
- Publication number
- JPS63225533A JPS63225533A JP5665787A JP5665787A JPS63225533A JP S63225533 A JPS63225533 A JP S63225533A JP 5665787 A JP5665787 A JP 5665787A JP 5665787 A JP5665787 A JP 5665787A JP S63225533 A JPS63225533 A JP S63225533A
- Authority
- JP
- Japan
- Prior art keywords
- precipitate
- barium ferrite
- barium
- ferrite powder
- alkali hydroxide
- 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.)
- Pending
Links
- AJCDFVKYMIUXCR-UHFFFAOYSA-N oxobarium;oxo(oxoferriooxy)iron Chemical compound [Ba]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O.O=[Fe]O[Fe]=O AJCDFVKYMIUXCR-UHFFFAOYSA-N 0.000 title claims abstract description 28
- 239000000843 powder Substances 0.000 title claims abstract description 19
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 38
- 239000002244 precipitate Substances 0.000 claims abstract description 21
- 229910001854 alkali hydroxide Inorganic materials 0.000 claims abstract description 13
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims abstract description 13
- 229910052788 barium Inorganic materials 0.000 claims abstract description 10
- 230000004907 flux Effects 0.000 claims abstract description 10
- 229910052742 iron Inorganic materials 0.000 claims abstract description 10
- 239000002002 slurry Substances 0.000 claims abstract description 10
- 238000010335 hydrothermal treatment Methods 0.000 claims abstract description 9
- 239000000203 mixture Substances 0.000 claims abstract description 9
- 150000003839 salts Chemical class 0.000 claims abstract description 3
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 9
- 239000000047 product Substances 0.000 claims description 8
- 239000007791 liquid phase Substances 0.000 claims description 6
- 239000007864 aqueous solution Substances 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 230000005415 magnetization Effects 0.000 abstract description 9
- 239000010419 fine particle Substances 0.000 abstract description 2
- 238000001354 calcination Methods 0.000 abstract 1
- 239000000463 material Substances 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 19
- 230000009467 reduction Effects 0.000 description 15
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 238000000034 method Methods 0.000 description 11
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- 229910052719 titanium Inorganic materials 0.000 description 5
- 238000009826 distribution Methods 0.000 description 4
- 238000001027 hydrothermal synthesis Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000002425 crystallisation Methods 0.000 description 3
- 230000008025 crystallization Effects 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 2
- 229910001626 barium chloride Inorganic materials 0.000 description 2
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 2
- 229910001863 barium hydroxide Inorganic materials 0.000 description 2
- IWOUKMZUPDVPGQ-UHFFFAOYSA-N barium nitrate Chemical compound [Ba+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O IWOUKMZUPDVPGQ-UHFFFAOYSA-N 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 150000001805 chlorine compounds Chemical class 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- -1 coprecipitation Chemical compound 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 229910052595 hematite Inorganic materials 0.000 description 2
- 239000011019 hematite Substances 0.000 description 2
- 150000002506 iron compounds Chemical class 0.000 description 2
- LIKBJVNGSGBSGK-UHFFFAOYSA-N iron(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Fe+3].[Fe+3] LIKBJVNGSGBSGK-UHFFFAOYSA-N 0.000 description 2
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- 239000012279 sodium borohydride Substances 0.000 description 2
- 229910000033 sodium borohydride Inorganic materials 0.000 description 2
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 150000001553 barium compounds Chemical class 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N iron(II,III) oxide Inorganic materials O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000006247 magnetic powder Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 150000007522 mineralic acids Chemical class 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- 235000013024 sodium fluoride Nutrition 0.000 description 1
- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 description 1
- 235000019345 sodium thiosulphate Nutrition 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 229910001631 strontium chloride Inorganic materials 0.000 description 1
- AHBGXTDRMVNFER-UHFFFAOYSA-L strontium dichloride Chemical compound [Cl-].[Cl-].[Sr+2] AHBGXTDRMVNFER-UHFFFAOYSA-L 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Landscapes
- Compounds Of Iron (AREA)
- Hard Magnetic Materials (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、水熱合成法で六角板状のマグネトブランバイ
ト型バリウムフェライト粉末を製造する方法の改良に関
するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a method for producing hexagonal plate-shaped magnetoblanbite-type barium ferrite powder by a hydrothermal synthesis method.
近年、磁気記録の高密度化の要求に伴い、バリウムフェ
ライトを磁気記録媒体として用いる垂直磁気記録方式の
開発が進められている。In recent years, with the demand for higher density magnetic recording, development of perpendicular magnetic recording systems using barium ferrite as a magnetic recording medium has been progressing.
垂直磁気記録方式に用いられるバリウムフェライトとし
ては、保磁力が適当な値（３００〜１５０００ｅ）で、
飽和磁化ができるだけ高く、粒子が小さく均一で、分散
性のよいものが望まれている。Barium ferrite used in the perpendicular magnetic recording system has a coercive force of an appropriate value (300 to 15,000e),
It is desired that the saturation magnetization is as high as possible, the particles are small and uniform, and the particles have good dispersibility.
（従来の技術）
従来、バリウムフェライトの製造方法としては、例えば
共沈法、ガラス結晶化法、水熱合成法等積々の方法が知
られており、水熱合成法については、例えば特公昭４６
−３５４５号公報、特開昭５６−１４９３２８号公報、
特開昭５６−１６０３２８号公報、特開昭５８−２２２
４号公報、特開昭５９−１６１００２号公報、特開昭５
９−１６４６４１号公報等で提案されている。(Prior art) Many methods have been known for producing barium ferrite, such as coprecipitation, glass crystallization, and hydrothermal synthesis. 46
-3545 publication, JP-A-56-149328 publication,
JP-A-56-160328, JP-A-58-222
Publication No. 4, JP-A-59-161002, JP-A-5
This method has been proposed in, for example, Japanese Patent No. 9-164641.
また、特開昭６１−１５２００３号公報、特開昭６１−
１３６９２３号公報には、バリウムフェライトの３価の
鉄原子の一部を２価の鉄原子に還元することが開示され
ている。Also, JP-A-61-152003, JP-A-61-152003,
Publication No. 136923 discloses reducing some of the trivalent iron atoms of barium ferrite to divalent iron atoms.
（発明が解決しようとする問題点）
水熱合成法により得られるバリウムフェライト粉末は一
般に粒子の凝集が少なく比較的分散性はよいが、従来公
知の方法では、飽和磁化が５５ｅｍ ｕ ／ ｇ程度と
低かったり、またバリウムフェライトの結晶化を進行さ
せて飽和磁化を向上させようとすると粒子間の焼結が生
じ易くなったりして、分散性が悪くなったりする難点が
あった。(Problems to be Solved by the Invention) Barium ferrite powder obtained by hydrothermal synthesis generally has relatively good dispersibility with little agglomeration of particles, but in conventional methods, the saturation magnetization is about 55 em u / g. Furthermore, if an attempt is made to improve the saturation magnetization by promoting crystallization of barium ferrite, sintering between particles tends to occur, resulting in poor dispersibility.
また、前記特開昭６１−１５２００３号公報、特開昭６
１−１３６９２３号公報において、３価の鉄原子を還元
する場合、還元処理をＨ２，ＣＯガス等により４００〜
９００℃という高温で気相で行っており、そのため、還
元装置に爆発、ガス漏れがないように安全ＭＷを施さね
ばならず、また気−固反応であるため、均一に還元を行
うことが難しいなどの問題があった。Also, the above-mentioned Japanese Patent Application Laid-Open No. 152003/1983, Japanese Patent Application Laid-open No. 6
In Publication No. 1-136923, when reducing trivalent iron atoms, the reduction treatment is performed using H2, CO gas, etc.
The process is carried out in the gas phase at a high temperature of 900°C, so a safe MW must be applied to the reduction equipment to prevent explosions and gas leaks, and because it is a gas-solid reaction, it is difficult to perform the reduction uniformly. There were other problems.
（発明の目的）
本発明の目的は、水熱合成法における前記難点を解決し
、３価の鉄原子の還元処理を安全かつ均一に行うことに
より、飽和磁化が高く、微粒子で分散性のよいバリウム
フェライト粉末を製造する方法を提供することにある。(Objective of the Invention) The object of the present invention is to solve the above-mentioned difficulties in the hydrothermal synthesis method, and to perform the reduction treatment of trivalent iron atoms safely and uniformly, thereby producing particles with high saturation magnetization, fine particles, and good dispersibility. An object of the present invention is to provide a method for manufacturing barium ferrite powder.
（問題点を解決するための手段）
本発明は、六方晶バリウムフェライト粉末を製造するに
当り、バリウム１グラム原子に対して鉄５〜１１グラム
原子を含有する金属塩の水溶液に、混合後の溶液中の水
酸化アルカリ濃度が３モル／９以上となるように水酸化
アルカリを加えて沈澱物を生成させ、該沈澱物を含むス
ラリを１３０〜３００℃で水熱処理した後、生成した沈
澱物に融剤を混合し、混合物を７５０〜９５０℃で焼成
し。(Means for Solving the Problems) In the present invention, in producing hexagonal barium ferrite powder, after mixing into an aqueous solution of a metal salt containing 5 to 11 grams of iron per 1 gram of barium, A precipitate is generated by adding alkali hydroxide so that the alkali hydroxide concentration in the solution is 3 mol/9 or more, and a slurry containing the precipitate is hydrothermally treated at 130 to 300 ° C., and then the generated precipitate A fluxing agent is mixed into the mixture, and the mixture is fired at 750 to 950°C.
得られた焼成物を液相に分散させ、還元剤によって三価
の鉄原子の１〜２０原子％を二価の鉄原子に還元するこ
とを特徴とするバリウムフェライト粉末の製造方法に関
するもので°ある。This invention relates to a method for producing barium ferrite powder, which comprises dispersing the obtained fired product in a liquid phase and reducing 1 to 20 at.% of trivalent iron atoms to divalent iron atoms using a reducing agent. be.
本発明においては、まずバリウムおよび鉄の化合物を水
に溶解し、これに水酸化アルカリを加えて沈澱物を生成
させる。In the present invention, barium and iron compounds are first dissolved in water, and alkali hydroxide is added thereto to form a precipitate.
バリウム化合物としては、硝酸バリウム、塩化バリウム
、水酸化バリウム等が用いられる。バリウムの使用量は
、バリウム濃度が０．０３〜０．２３モル／ｊの範囲に
なるようにするのが六角板状の形状のよい粒子を得るう
えで望ましい。As the barium compound, barium nitrate, barium chloride, barium hydroxide, etc. are used. The amount of barium used is preferably such that the barium concentration is in the range of 0.03 to 0.23 mol/j in order to obtain particles with a good hexagonal plate shape.
鉄化合物としては、硝酸第二鉄、塩化第二鉄等が用いら
れる。鉄の使用量はバリウム１グラム原子に対して、５
〜１１グラム原子である。鉄の量が少なすぎると、マグ
ネトブランバイト型バリウムフェライトの生成量が少な
く、形状も六角板状でなくなる。また鉄の量が多すぎる
とヘマタイトが副生じたり、またバリウムフェライトの
粒子が大きくなり、磁気特性も劣ってくる。As the iron compound, ferric nitrate, ferric chloride, etc. are used. The amount of iron used is 5 for 1 gram atom of barium.
~11 gram atoms. If the amount of iron is too small, the amount of magnetobrambite barium ferrite produced will be small and the shape will not be hexagonal plate-like. Furthermore, if the amount of iron is too large, hematite will be produced as a by-product, and barium ferrite particles will become large, resulting in poor magnetic properties.
水酸化アルカリとしては、水酸化ナトリウム、水酸化カ
リウム等が用いられる。水酸化アルカリの使用量は水酸
化アルカリを混合した後の溶液中の水酸化アルカリ濃度
が３モル／ｊ以上となる量が必要であり、５〜８モル／
ｊの範囲が好ましい。As the alkali hydroxide, sodium hydroxide, potassium hydroxide, etc. are used. The amount of alkali hydroxide used must be such that the alkali hydroxide concentration in the solution after mixing the alkali hydroxide is 3 mol/j or more, and 5 to 8 mol/j.
A range of j is preferred.
水酸化アルカリの量が少なすぎると粒子が大きくなった
り、粒度分布が広くなったり、またへマタイトが生成す
る。また水酸化アルカリを過度に多くするのは経済的で
ない。If the amount of alkali hydroxide is too small, the particles become large, the particle size distribution becomes wide, and hematite is generated. Further, it is not economical to increase the amount of alkali hydroxide excessively.
バリウムおよび鉄を含有する水溶液に水酸化アル男りを
混合する方法については、特に制限はないが１例えばバ
リウムおよび鉄を含有する水溶液に、直接水酸化アルカ
リを添加するか、あるいは水酸化アルカリの水溶液を添
加する方法がある。There are no particular restrictions on the method of mixing alkaline hydroxide into an aqueous solution containing barium and iron; There is a method of adding an aqueous solution.
あるいはバリウムおよび鉄の水溶液調製時に添加する方
法を採用してもよい。Alternatively, a method of adding barium and iron at the time of preparing an aqueous solution may be adopted.
さらに、予め出発原料の水溶液に従来のバリウムフェラ
イトに添加されている種々の元素、例えばＣｏ、Ｎｉ、
Ｍｎ、Ｚｎ、Ｃａ、Ｐｂ、Ｓｒ、Ｔｉ、Ｉ ｎ、Ｎｂ、
Ｌ、ａ’、Ｃｅ、Ｐｒ、Ｓｍなどの化合物、例えば塩化
物、硝酸塩などを若干添加することができ、特にＣＯお
よびＴｉの化合物の添加は保磁力をコントロールするう
えで好ましい。Furthermore, various elements such as Co, Ni,
Mn, Zn, Ca, Pb, Sr, Ti, In, Nb,
A small amount of compounds such as L, a', Ce, Pr, and Sm, such as chlorides and nitrates, can be added, and addition of CO and Ti compounds is particularly preferable for controlling the coercive force.
ＣｏおよびＴｉの化合物としては、塩化物、硝酸塩、ア
ルコキシドなどが使用される。その添加量は鉄原子に対
して、原子比でＣｏ／Ｆｅ、Ｔｉ／Ｆｅがそれぞれ０．
０１〜０．２０の範囲が好適である。As the Co and Ti compounds, chlorides, nitrates, alkoxides, etc. are used. The amount of Co/Fe and Ti/Fe in atomic ratio is 0.0, respectively, relative to iron atoms.
A range of 0.01 to 0.20 is suitable.
次に、沈ｖｉ物を含むスラリを水熱処理することにより
、バリウムフェライトの微細な結晶が生成、沈澱する。Next, by subjecting the slurry containing the precipitate to hydrothermal treatment, fine crystals of barium ferrite are generated and precipitated.
水熱処理の温度は１３０〜３００℃、好ましくは１５０
〜２７０℃である。温度が低すぎると結晶の生成が充分
でなく、また温度が高すぎると最終的に得られるバリウ
ムフェライト粉末の粒径が大きくなるので好ましくない
、水熱処理時間は普通、０．５〜４０時間程度であり、
水熱処理には通常、オートクレーブが採用される。The temperature of hydrothermal treatment is 130-300℃, preferably 150℃
~270°C. If the temperature is too low, crystal formation will not be sufficient, and if the temperature is too high, the particle size of the final barium ferrite powder will become large, which is undesirable.The hydrothermal treatment time is usually about 0.5 to 40 hours. and
Autoclaves are usually employed for hydrothermal treatment.
次いで、水熱処理により生成した＠紺な結晶の沈澱物を
水洗して、遊離のアルカリ分を除去した後、得られた沈
澱物に融剤を混合する。融剤としては、塩化ナトリウム
、塩化カリウム、塩化リチウム、塩化バリウム、塩化ス
トロンチウムおよびフ・ｌ化ナトリウムのうち少なくと
も一種が用いられる。融剤の使用量は沈澱物（乾燥物基
準）に対して、１０〜１８０重量％、好ましくは３０〜
１２０重量％が適当である。融剤の量が少なすぎると粒
子の焼結が起り、また多すぎても多くしたことによる利
点はなく、経済的でない、沈澱物と融剤の混合方法は特
に制限はなく、例えば沈澱物のスラリに融剤を加えて湿
式混合した後、スラリを乾燥してもよく、あるいは沈澱
物を乾燥した後、融剤を加えて乾式混合してもよい。Next, the precipitate of dark blue crystals produced by the hydrothermal treatment is washed with water to remove free alkali, and then a flux is mixed with the precipitate obtained. As the flux, at least one of sodium chloride, potassium chloride, lithium chloride, barium chloride, strontium chloride, and sodium fluoride is used. The amount of flux used is 10 to 180% by weight, preferably 30 to 180% by weight, based on the precipitate (dry basis).
120% by weight is suitable. If the amount of flux is too small, sintering of the particles will occur, and if it is too large, there is no advantage of increasing it and it is not economical. There is no particular restriction on the method of mixing the precipitate and the flux. After adding a flux to the slurry and wet-mixing, the slurry may be dried, or alternatively, after drying the precipitate, a flux may be added and dry-mixed.
次いで、得られた混合物を焼成することにより、バリウ
ムフェライトの結晶化が完全に行われる。Next, the resulting mixture is fired to completely crystallize the barium ferrite.
焼成温度は７５０〜９５０℃、好ましくは８００〜９３
０°Ｃが適当である。温度が低すぎると結晶化が進まず
、飽和磁化が低くなる。また温度が高すぎると粒子が大
きくなったり、焼結が起こるので好ましくない、焼成時
間は１〜３０時間程度が適当である。焼成雰囲気は特に
制限されないが、−ａには空気雰囲気が便利である。Firing temperature is 750-950°C, preferably 800-93°C
0°C is appropriate. If the temperature is too low, crystallization will not proceed and the saturation magnetization will become low. Further, if the temperature is too high, the particles will become large or sintering will occur, which is not preferable.The firing time is preferably about 1 to 30 hours. The firing atmosphere is not particularly limited, but an air atmosphere is convenient for -a.
次に得られた焼成物を洗浄する。洗浄は焼成物中の融剤
、過剰のバリウムなどの不純物を十分に除去できればよ
とのような方法で行ってもよい。Next, the obtained fired product is washed. The cleaning may be carried out by any method as long as impurities such as flux and excess barium in the fired product can be sufficiently removed.
洗浄液としては水や硝酸、塩酸などの無機酸、酢酸、１
０ピオン酸などの有機酸などを用いることができる。Cleaning liquids include water, inorganic acids such as nitric acid and hydrochloric acid, acetic acid,
Organic acids such as 0 pionic acid can be used.
次いで、洗浄により得られた焼成物を含むスラリ中に還
元剤を加えて、液相で三価の鉄原子の一部を二価の鉄原
子に還元する。還元剤としてはヒドラジン（ＮＨ２−Ｎ
Ｈ２）、ホルマリン（ＨＣＨＯ’）塩化第−ｆｌＪ（Ｓ
ｎ ＣＪ ２）、チオ硫酸ナトリウム（Ｎａ２Ｓ２０
３）、水素化ホウ素ナトリウム（ＮａＢＨ４）等が用い
られる。三価の鉄原子の還元はその１〜２０原千％が二
価の鉄原子に変わるように行う０通常２０〜７０℃の温
度範囲で１〜４０時間処理すると所望の還元が達成され
る。三価の鉄原子の還元量が少なすぎると飽和磁化がほ
とんど向上しない、また多すぎると表面層のマグネタイ
トの析出が顕著となり、得られる磁性粉の結晶形が六方
晶系から外れてくるため好ましくない。Next, a reducing agent is added to the slurry containing the fired product obtained by washing to reduce some of the trivalent iron atoms to divalent iron atoms in the liquid phase. Hydrazine (NH2-N
H2), formalin (HCHO') chloride-flJ (S
n CJ 2), sodium thiosulfate (Na2S20
3), sodium borohydride (NaBH4), etc. are used. The reduction of trivalent iron atoms is carried out so that 1 to 20,000% of them are converted to divalent iron atoms. The desired reduction is usually achieved by treatment at a temperature range of 20 to 70° C. for 1 to 40 hours. If the amount of reduction of trivalent iron atoms is too small, the saturation magnetization will hardly improve, and if it is too large, precipitation of magnetite in the surface layer will become noticeable, and the crystal shape of the obtained magnetic powder will deviate from the hexagonal system, so it is preferable. do not have.
本発明においては、三価の鉄原子の還元を液相で行うた
め、従来のように１・■２、ＣＯガス等を用いて気相で
還元処理を行う場合に比べて、危険性は全くなく、安全
であり、さらにバリウムフェライト粉末が液相に均一に
分散されているので、還元も均一に行える。In the present invention, since the reduction of trivalent iron atoms is carried out in the liquid phase, there is no danger at all compared to the conventional reduction treatment in the gas phase using 1, 2, CO gas, etc. Furthermore, since barium ferrite powder is uniformly dispersed in the liquid phase, reduction can be performed uniformly.
次いで還元処理を施した焼成物ご洗浄し、２７′７過、
乾燥することにより、バリウムフェライト粉末が得られ
る。Next, the fired product subjected to reduction treatment was washed, passed through 27'7,
By drying, barium ferrite powder is obtained.
（実施例）
実施例１
水２７００ｍｊ）に、硝酸第二鉄［Ｆｅ（ＮＯ３）３・
９Ｈ２０］を２６７モル、硝酸ヨバルｔ−［Ｃ。(Example) Example 1 Ferric nitrate [Fe(NO3)3.
9H20], 267 mol of tert-[C] nitrate.
（Ｎｏ ） ・６Ｈ２０１を０．２２モルおよび四基
化チタン（Ｔ ｉＣＪ ４）を０．２２モル、水酸化バ
リウム［Ｂ ａ （ＯＨ） ２ ・８ Ｈ２０］を０．
３９モルおよび水酸化ナトリウム（ＮａＯＨ＞を３０モ
ル添加し、撹拌して沈ｒｉ物を生成させた。沈澱物生成
後のスラリ中のＮａｏＨｆｉ度は７．３モル／ｌであっ
た。得られた沈澱物を含むスラリをオートクレーブに入
れ、１９０℃で２０時間水熱処理を行った０次いで得ら
れた沈澱物を十分に水洗した後、濾過、乾燥し、これに
融剤としてＮａＣＪとＢａＣｌ２・２Ｈ２０との重量比
がｌ：ｌの混合物を沈澱物に対して１００重量％加えて
乾式混合した。(No) 0.22 mol of 6H201, 0.22 mol of titanium tetrahydride (T iCJ 4), and 0.22 mol of barium hydroxide [B a (OH) 2 .8 H20].
39 mol and 30 mol of sodium hydroxide (NaOH>) were added and stirred to form a precipitate.The degree of NaOH in the slurry after forming the precipitate was 7.3 mol/l. The slurry containing the precipitate was placed in an autoclave and subjected to hydrothermal treatment at 190°C for 20 hours.Then, the obtained precipitate was thoroughly washed with water, filtered and dried, and NaCJ and BaCl2.2H20 were added as fluxing agents. A mixture having a weight ratio of 1:1 was added to the precipitate in an amount of 100% by weight and dry mixed.
この混合物を空気雰囲気下で９００”Ｃで６０分間焼成
した。得られた焼成物を水で十分水洗した後、１０％ヒ
ドラジン溶液を加えて、５０℃で４時間保持した０次い
で焼成物を水洗し、濾過、乾燥してバリウムフェライト
粉末を得た。This mixture was fired at 900"C for 60 minutes in an air atmosphere. After thoroughly washing the resulting fired product with water, a 10% hydrazine solution was added and the mixture was maintained at 50°C for 4 hours. Then, the fired product was washed with water. The mixture was filtered and dried to obtain barium ferrite powder.
得られたバリウムフェライト粉末を分析した結果、三価
の鉄原子の５．６原子％が還元されて二価の鉄原子にな
°つていた。Analysis of the obtained barium ferrite powder revealed that 5.6 atomic percent of the trivalent iron atoms were reduced to divalent iron atoms.
また得られたバリウムフェライト粉末について透過型電
子顕微鏡（ＴＥＭ）で粒子形状（粒径、厚み、分布）を
測定した結果（粒子１００個の平均値）および振動試料
式磁力計で磁気特性を測定した結果を第２表に示す。In addition, the particle shape (particle size, thickness, distribution) of the obtained barium ferrite powder was measured using a transmission electron microscope (TEM) (average value of 100 particles), and the magnetic properties were measured using a vibrating sample magnetometer. The results are shown in Table 2.
実施例２〜４
実施例１の還元条件を第１表に示すとおりにかえたほか
は、実施例１と同様にしてバリウムフェライト粉末を製
造し、粒子形状、磁気特性等を測定した。その結果を第
２表に示す。Examples 2 to 4 Barium ferrite powder was produced in the same manner as in Example 1, except that the reduction conditions of Example 1 were changed as shown in Table 1, and the particle shape, magnetic properties, etc. were measured. The results are shown in Table 2.
比較例１
実施例１においてヒドラジンによって還元処理を施さな
かったほかは、実施例１と同様にしてバリウムフェライ
ト粉末を製造し１粒子形状、磁気特性等を測定した。そ
の結果を第２表に示す。Comparative Example 1 Barium ferrite powder was produced in the same manner as in Example 1, except that the reduction treatment with hydrazine was not performed, and the particle shape, magnetic properties, etc. were measured. The results are shown in Table 2.
第１表
（発明の効果）
本発明によれば、結晶状態が良く、六角板状で平均粒径
１１００ｎ以下、粒度分布１００〜３０ｎｍの微小で均
一であり、飽和磁化が５６ ｅ ｒｎ ｕ ７８以上で
あるマグネトブランバイト型バリウムフェライト粉末を
得ることができる。またこのバリウムフェライト粉末は
分散性、平滑性が良好で、板状比が３〜１５の範囲にあ
り、３００〜１５０００ｅの保磁力および５６ｅｍｕ、
’ｇ以上の高い飽和磁化を示す、さらに保磁力について
は、前記したＴｉおよびＣｏを添加することにより、自
由にコントロールすることができる。Table 1 (Effects of the Invention) According to the present invention, the crystal state is good, the average grain size is 1100 nm or less in a hexagonal plate shape, the particle size distribution is small and uniform with a particle size distribution of 100 to 30 nm, and the saturation magnetization is 56 e r n u 78 or more. Magnetobrambite barium ferrite powder can be obtained. In addition, this barium ferrite powder has good dispersibility and smoothness, has a plate ratio in the range of 3 to 15, has a coercive force of 300 to 15000e, and has a coercive force of 56 emu,
The coercive force, which exhibits a high saturation magnetization of >'g, can be freely controlled by adding the above-mentioned Ti and Co.
さらに、本発明におりては、三価の鉄原子の還元を液相
で行うため、従来の気相還元の場合の危険性が全くなく
、安全であり、還元も均一に行える。Furthermore, in the present invention, since trivalent iron atoms are reduced in a liquid phase, there is no danger associated with conventional gas phase reduction, which is safe, and the reduction can be performed uniformly.
Claims (1)
リウム１グラム原子に対して鉄５〜１１グラム原子を含
有する金属塩の水溶液に、混合後の溶液中の水酸化アル
カリ濃度が３モル／ｌ以上となるように水酸化アルカリ
を加えて沈澱物を生成させ、該沈澱物を含むスラリを１
３０〜３００℃で水熱処理した後、生成した沈澱物に融
剤を混合し、混合物を７５０〜９５０℃で焼成し、得ら
れた焼成物を液相に分散させ、還元剤によつて三価の鉄
原子の１〜２０原子％を二価の鉄原子に還元することを
特徴とするバリウムフェライト粉末の製造方法。In producing hexagonal barium ferrite powder, an aqueous solution of a metal salt containing 5 to 11 gram atoms of iron per 1 gram atom of barium is mixed with an alkali hydroxide concentration of 3 mol/l or more. Add alkali hydroxide to form a precipitate, and add the slurry containing the precipitate to 1
After hydrothermal treatment at 30-300°C, a flux is mixed with the generated precipitate, the mixture is fired at 750-950°C, the resulting fired product is dispersed in the liquid phase, and trivalent 1. A method for producing barium ferrite powder, which comprises reducing 1 to 20 at.% of iron atoms into divalent iron atoms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5665787A JPS63225533A (en) | 1987-03-13 | 1987-03-13 | Production of barium ferrite powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5665787A JPS63225533A (en) | 1987-03-13 | 1987-03-13 | Production of barium ferrite powder |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63225533A true JPS63225533A (en) | 1988-09-20 |
Family
ID=13033454
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5665787A Pending JPS63225533A (en) | 1987-03-13 | 1987-03-13 | Production of barium ferrite powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63225533A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61136923A (en) * | 1984-12-07 | 1986-06-24 | Fuji Photo Film Co Ltd | Hexagonal ferrite magnetic body for magnetic recording and its manufacture |
| JPS61168532A (en) * | 1984-08-23 | 1986-07-30 | Sakai Chem Ind Co Ltd | Production of fine crystal powder of barium ferrite |
-
1987
- 1987-03-13 JP JP5665787A patent/JPS63225533A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61168532A (en) * | 1984-08-23 | 1986-07-30 | Sakai Chem Ind Co Ltd | Production of fine crystal powder of barium ferrite |
| JPS61136923A (en) * | 1984-12-07 | 1986-06-24 | Fuji Photo Film Co Ltd | Hexagonal ferrite magnetic body for magnetic recording and its manufacture |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5057299A (en) | Method for making beta cobaltous hydroxide | |
| KR960002625B1 (en) | Process for producing microcrystalline barium ferrite platelets | |
| JPS63225533A (en) | Production of barium ferrite powder | |
| JPH0526727B2 (en) | ||
| JPS6259531A (en) | Production of barium ferrite powder | |
| JPS63233017A (en) | Magnetic powder of barium ferrite and its production | |
| JPS61295237A (en) | Production of barium ferrite powder | |
| JPS62207720A (en) | Preparation of barium ferrite powder | |
| JP2889354B2 (en) | Acicular barium ferrite magnetic powder and method for producing the same | |
| JPS62252324A (en) | Production of fine barium ferrite powder | |
| JPS62235220A (en) | Production of ferromagnetic fine powder for magnetic recording | |
| JPS63162531A (en) | Production of barium ferrite powder | |
| JP3328017B2 (en) | Method for producing acicular hexagonal ferrite magnetic powder having perpendicular magnetic anisotropy | |
| JPS6090828A (en) | Manufacture of needlelike spinel ferrite powder | |
| JPH02133323A (en) | Production of magnetic powder of magnetoplumbite type ferrite | |
| JPS62209807A (en) | Preparation of barium ferrite particulate for magnetic recording | |
| JPS6256325A (en) | Production of barium ferrite powder | |
| JPS632813A (en) | Production of particulate powder of lamellate ba ferrite for magnetic recording | |
| JP2806618B2 (en) | Method for producing acicular barium ferrite magnetic powder | |
| JPS63307122A (en) | Barium ferrite magnetic powder and production thereof | |
| JPH04362020A (en) | Ferritic magnetic powder and its production | |
| JPH0614486B2 (en) | Plate-shaped composite ferrite fine particle powder for magnetic recording and method for producing the same | |
| JPS63310729A (en) | Production of hexagonal magnetoplumbite type ferrite magnetic powder | |
| JPH06104575B2 (en) | Method for producing tabular Ba ferrite fine particle powder | |
| JPS6312107A (en) | Manufacture of superfine barium ferrite superfine grain |