JPS6310096B2 - - Google Patents
Info
- Publication number
- JPS6310096B2 JPS6310096B2 JP58167563A JP16756383A JPS6310096B2 JP S6310096 B2 JPS6310096 B2 JP S6310096B2 JP 58167563 A JP58167563 A JP 58167563A JP 16756383 A JP16756383 A JP 16756383A JP S6310096 B2 JPS6310096 B2 JP S6310096B2
- Authority
- JP
- Japan
- Prior art keywords
- ferrite
- beads
- powder
- spherical
- slurry
- 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.)
- Expired
Links
- 229910000859 α-Fe Inorganic materials 0.000 claims description 43
- 239000000843 powder Substances 0.000 claims description 40
- 239000011324 bead Substances 0.000 claims description 29
- 238000010304 firing Methods 0.000 claims description 26
- 239000002002 slurry Substances 0.000 claims description 24
- 229910044991 metal oxide Inorganic materials 0.000 claims description 17
- 150000004706 metal oxides Chemical class 0.000 claims description 17
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 14
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 11
- 239000001301 oxygen Substances 0.000 claims description 11
- 229910052760 oxygen Inorganic materials 0.000 claims description 11
- 239000002253 acid Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 238000001354 calcination Methods 0.000 claims description 5
- 159000000007 calcium salts Chemical class 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 230000001590 oxidative effect Effects 0.000 claims description 5
- 150000003863 ammonium salts Chemical class 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 238000001694 spray drying Methods 0.000 claims description 4
- 229920005610 lignin Polymers 0.000 claims description 3
- 159000000000 sodium salts Chemical class 0.000 claims description 3
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 claims description 2
- 238000005245 sintering Methods 0.000 description 17
- 238000000034 method Methods 0.000 description 13
- 238000006243 chemical reaction Methods 0.000 description 11
- 239000007921 spray Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 239000007787 solid Substances 0.000 description 10
- 239000011812 mixed powder Substances 0.000 description 9
- 239000011230 binding agent Substances 0.000 description 8
- 238000005469 granulation Methods 0.000 description 8
- 230000003179 granulation Effects 0.000 description 8
- 239000013078 crystal Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 229910001873 dinitrogen Inorganic materials 0.000 description 6
- 230000005415 magnetization Effects 0.000 description 5
- 239000008187 granular material Substances 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical compound OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000007873 sieving Methods 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 238000000498 ball milling Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000009766 low-temperature sintering Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- -1 sulfonic acid sodium salt Chemical class 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Landscapes
- Developing Agents For Electrophotography (AREA)
- Compounds Of Iron (AREA)
Description
【発明の詳細な説明】
本発明は、例えば静電写真用のキヤリヤー粉と
して使用されるフエライト球状粉の製造法に関す
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing spherical ferrite powder used as a carrier powder for electrostatic photography, for example.
従来、この種のフエライト球状粉の製造法とし
て、例えば特開昭52−56536号、特開昭58−
123548号、特開昭58−123549号、特開昭58−
123550号、特開昭58−123551号、特開昭58−
123552号、特開昭58−123553号、特開昭58−
123554号、特開昭58−123555号公報などに記載さ
れているように、二段階焼成を採用するのが一般
的であつた。すなわち、従来にあつては、基本的
には、
フエライト形成金属酸化物配合粉
↓
假焼（800〜1200℃で一次焼成）
↓
粉砕（約1μ程度まで粉砕）
↓
造粒（有機バインダー使用）
↓
焼成（1100〜1400℃でフエライトに本焼成）
↓
製 品
という工程を採用しており、フエライト形成組成
配合粉を一旦焼成（一次焼成）し、これを粉砕し
て造粒したうえフエライトに本焼成するという二
段階焼成処方が通常であつた。 Conventionally, methods for producing this type of spherical ferrite powder have been disclosed, for example, in JP-A-52-56536 and JP-A-58-
No. 123548, Japanese Patent Application Publication No. 123549, Japanese Patent Application Publication No. 1983-
No. 123550, JP-A No. 123551, JP-A-58-
No. 123552, JP-A No. 123553, JP-A-58-
As described in JP-A No. 123554 and Japanese Unexamined Patent Application Publication No. 123555/1983, it was common to employ two-stage firing. In other words, in the past, basically, ferrite-forming metal oxide blended powder ↓ Calcining (primary firing at 800-1200℃) ↓ Grinding (pulverizing to about 1μ) ↓ Granulation (using organic binder) ↓ The process of firing (main firing into ferrite at 1100-1400℃) ↓ product is adopted, in which the ferrite-forming composition blended powder is fired once (primary firing), this is crushed and granulated, and then main firing is performed to form ferrite. A two-step firing recipe was the norm.
本発明の目的は、このような従来の二段階焼成
法に代えて、一段焼成法とも言うべき一次焼成工
程と粉砕工程を省略しても良品質のフエライト球
状粉を製造することができる方法を提供するにあ
る。 The purpose of the present invention is to develop a method that can produce high-quality spherical ferrite powder even if the primary firing step and the crushing step, which is also called a one-stage firing method, are omitted, instead of the conventional two-stage firing method. It is on offer.
後記の比較例でも示すように、通常の処方に従
う場合には、もし一次焼成を省略すると、緻密で
強度の大きな流動性に富む均一フエライト球状粉
が製造できない。これは、フエライト形成金属酸
化物粉を一次焼成せずにそのまま造粒したのでは
質のよいビーズが作れないことによる。すなわち
フエライト形成粒子酸化物粉は通常1μ以下の微
粉でありかつ嵩密度が小さいので、これをスラリ
ー状にする場合、適度の粘度では固体濃度をあげ
ることができない。加えて、先の公報にも記され
ているように、有機バインダー例えばポリビニー
ルアルコールなどを使用すると、これは粘性を高
めるからなおさら固体濃度を上げることができな
くなる。従つてこれを噴霧乾燥して造粒したので
は、締りのない密度のかるいものとならざるを得
ない。特に、ポリビニールアルコールなどのバイ
ンダーを使用する場合には、スラリーにエアーを
巻き込みやすくなつて空洞の多い形状の不均一の
粒子に造粒されることになる。従つてこのような
質の悪いビーズをフエライトに焼成しても緻密で
強度の大きな流動性に富む均一フエライト球状粉
が製造できない。このようなことからフエライト
形成金属酸化物粉をいつたん一次焼成しこれを粉
砕し高い固体濃度をもつスラリーにして造粒する
処方が従来より採用されていた。 As shown in the comparative example below, when a normal recipe is followed, if the primary firing is omitted, it is not possible to produce a uniform spherical ferrite powder that is dense, strong, and highly fluid. This is because beads of good quality cannot be produced if the ferrite-forming metal oxide powder is granulated as it is without being primarily fired. That is, since the ferrite-forming particle oxide powder is usually a fine powder of 1 μm or less and has a small bulk density, when it is made into a slurry, it is not possible to increase the solid concentration with a moderate viscosity. In addition, as mentioned in previous publications, the use of organic binders such as polyvinyl alcohol increases the viscosity, making it even more difficult to increase the solids concentration. Therefore, if this is granulated by spray drying, it will inevitably be loose and light in density. In particular, when a binder such as polyvinyl alcohol is used, air is likely to be drawn into the slurry, resulting in granulation into non-uniform particles with many cavities. Therefore, even if such poor quality beads are fired into ferrite, it is impossible to produce a uniform spherical ferrite powder that is dense, strong, and highly fluid. For this reason, a recipe has conventionally been adopted in which a ferrite-forming metal oxide powder is first fired and then pulverized to form a slurry with a high solids concentration and granulated.
本発明者らは前記目的のもとで種々の試験研究
を重ねたところ、この一次焼成を省略しても、ス
ラリー添加剤を適切に選択し、その造粒品を酸素
濃度が１％以下の非酸化性雰囲気で焼成するなら
ば、おそらくは、スラリー添加剤がこの焼成過程
でフエライト形成反応に有利に関与するものと考
えられるが、二段階焼成法に比して優るとも劣ら
ない良品質のフエライト球状粉が製造できること
を見いだした。すなわち本発明は、フエライト形
成組成の金属酸化物粉を予備焼成することなく水
に分散させ、このスラリーを噴霧乾燥して実質的
に球状のビーズとし、このビーズをフエライトに
焼成して球状フエライト粒子を得るにあたり、前
記スラリーを形成するさいに該金属酸化物粉に対
する重量基準で0.1〜３重量％のポリビニールア
ルコールと、0.01〜５重量％のポリカルボン酸ま
たはリグニンスルホン酸のナトリウム塩、アンモ
ニウム塩またはカルシウム塩のいづれか一種また
は二種以上とを添加して該ビーズに造粒し、この
ビーズをフエライトに焼成するさいに酸素濃度が
１％以下の実質上非酸化性雰囲気下で焼成するこ
とを特徴とするフエライト球状粉の製造法を提供
するものである。本発明法に従うと、低い温度で
フエライト焼成反応が良好に進行するという予想
外の現象が起こり、この低温焼成でも緻密でかつ
強度の大きいフエライト球状粉が得られる。 The inventors of the present invention have repeatedly conducted various tests and studies based on the above objective, and have found that even if this primary calcination is omitted, the slurry additive can be appropriately selected and the granulated product can be produced with an oxygen concentration of 1% or less. If the firing is performed in a non-oxidizing atmosphere, the slurry additive probably participates favorably in the ferrite formation reaction during this firing process, but the ferrite quality is as good as the two-step firing method. It was discovered that spherical powder can be produced. That is, the present invention involves dispersing metal oxide powder with a ferrite-forming composition in water without pre-calcination, spray-drying this slurry to form substantially spherical beads, and firing the beads into ferrite to form spherical ferrite particles. When forming the slurry, 0.1 to 3% by weight of polyvinyl alcohol and 0.01 to 5% by weight of polycarboxylic acid or lignin sulfonic acid sodium salt or ammonium salt, based on the weight of the metal oxide powder. Alternatively, one or more types of calcium salts are added to the beads, and when the beads are fired into ferrite, the beads are fired in a substantially non-oxidizing atmosphere with an oxygen concentration of 1% or less. The present invention provides a method for producing characteristic spherical ferrite powder. According to the method of the present invention, an unexpected phenomenon occurs in which the ferrite sintering reaction progresses favorably at low temperatures, and even at this low temperature sintering, dense and strong ferrite spherical powder can be obtained.
以下に本発明の詳細を説明する。 The details of the present invention will be explained below.
前述のように、本発明の基本的な特徴は、フエ
ライト形成金属酸化物粉をなまのまま（假焼する
ことなく）で特定配合の有機バインダーを使用し
て造粒し、非酸化性雰囲気でフエライトに焼成す
るという一段焼成法にあるが、ここで使用する有
機バインダーが単なるバインダーとしての作用の
他に、焼成時にフエライト反応および焼結反応の
促進作用を示すことを見いだした点にある。 As mentioned above, the basic characteristics of the present invention are that the ferrite-forming metal oxide powder is granulated as is (without calcining) using a specific blend of organic binder, and then granulated in a non-oxidizing atmosphere. The present invention is based on a one-stage firing method in which ferrite is fired in a single step, but it has been discovered that the organic binder used here not only acts as a binder, but also promotes the ferrite reaction and sintering reaction during firing.
ポリビニールアルコールを使用して造粒するこ
と自体は前掲公報にも記載されているが、この従
来の一次焼成品に代えて、なまのままで（すなわ
ち假焼することなく）フエライト形成金属酸化物
粉を直接スラリー化し、これにポリビニールアル
コールを添加して造粒することを試みた結果、後
記比較例に示すように、このポリビニールアルコ
ールだけではその造粒品は形状は球形とはなるも
のの空洞が多く締りも不足した不均一品しか得ら
れないのに対し、これに適切な界面活性剤例えば
ポリカルボン酸またはリグニンスルホン酸のニト
リウム塩、アンモニウム塩またはカルシウム塩の
いづれか一種または二種以上を適量追添すると、
密度が大きく空洞の無い均一な良好なビーズが得
られることがわかつた。この場合、ポリビニール
アルコールの添加量は、該金属酸化物粉に対する
重量基準で0.1重量％以上は必要であるが、あま
り多いとスラリーの粘度が上昇するので３重量％
以下とし、ポリカルボン酸またはリグニンスルホ
ン酸のナトリウム塩、アンモニウム塩またはカル
シウム塩のいづれか一種または二種以上の添加量
は、同じく金属酸化物粉に対する重量基準で0.01
〜５重量％、好ましくは0.1〜1.0重量％の範囲と
するのがよく、これによつて、假焼品ではなくて
も、粘性が低く固体濃度の高いスラリーが形成で
きこれを噴霧乾燥するとエアーの巻き込みの無い
高密度のビーズ（空洞がなく中実で締まつた均一
なビーズ）を作ることができる。 Granulation using polyvinyl alcohol is also described in the above-mentioned publication, but instead of this conventional primary firing product, ferrite-forming metal oxidation can be used as it is (that is, without firing). As a result of trying to slurry the powder directly and granulating it by adding polyvinyl alcohol to it, we found that the granulated product did not have a spherical shape with only this polyvinyl alcohol, as shown in the comparative example below. Only a heterogeneous product with many cavities and insufficient firmness can be obtained, but suitable surfactants such as one or more of nitrium salts, ammonium salts, or calcium salts of polycarboxylic acid or ligninsulfonic acid are used. When you add an appropriate amount of
It was found that good, uniform beads with high density and no cavities could be obtained. In this case, the amount of polyvinyl alcohol added needs to be 0.1% by weight or more based on the weight of the metal oxide powder, but if it is too large, the viscosity of the slurry will increase, so it should be 3% by weight.
The amount of addition of one or more of the sodium salt, ammonium salt, or calcium salt of polycarboxylic acid or ligninsulfonic acid is 0.01% by weight based on the metal oxide powder.
~5% by weight, preferably in the range of 0.1 to 1.0% by weight, which allows the formation of a slurry with low viscosity and high solids concentration, even if it is not a calcined product, which can be spray dried with air. It is possible to make high-density beads (solid, tight, uniform beads with no cavities) without any entanglement.
このようにして製造したビーズを焼成するので
あるが、その焼成雰囲気を酸素濃度が１％以下、
好ましくは0.2％以下の実質上非酸化性雰囲気と
して実施すると、低温でも焼結反応が十分に進行
し、表面の結晶が成長して緻密な焼成品が得られ
る。酸素濃度が１％を越えるような、さらには前
掲公報に示されているように大気雰囲気下で焼成
すると、その昇温時に有機バインダーが燃えてし
まつて焼結反応への関与は起きない。窒素ガスそ
の他の不活性ガス雰囲気下のもとで前記のように
酸素濃度を低くした条件下でこの焼結を行う場合
には、おそらく、昇温過程で有機バインダーは分
解するものの還元性物質が生成し（あるいは還元
性雰囲気が生じ）、これがフエライト反応および
焼結反応を促進するなんらかの作用を供するもの
と推案される。例えば後記実施例でも示すが、従
来法の場合には1250℃程度の焼結温度を必要とし
たフエライト生成反応が本発明の場合には1100℃
程度の温度で焼結を実施しても十分にフエライト
結晶の成長がおこり、緻密で強度の大きな流動性
の良いフエライト球状粉が製造できるのである。
なお、このような作用はポリビニールアルコール
単独添加（界面活性剤無添加）でも生じるが、こ
の場合には、得られるフエライト球状粉は密度と
流動性の面で本発明品に劣るものとなる。 The beads produced in this way are fired, and the firing atmosphere is such that the oxygen concentration is 1% or less.
If the sintering reaction is carried out in a substantially non-oxidizing atmosphere of preferably 0.2% or less, the sintering reaction will proceed sufficiently even at low temperatures, crystals on the surface will grow, and a dense fired product will be obtained. If the oxygen concentration exceeds 1%, or even if it is fired in the air as shown in the above-mentioned publication, the organic binder will burn when the temperature is raised and will not participate in the sintering reaction. If this sintering is carried out in an atmosphere of nitrogen gas or other inert gas with a low oxygen concentration as described above, the organic binder will probably decompose during the heating process, but reducing substances will be removed. It is presumed that the ferrite reaction and sintering reaction are promoted by the ferrite reaction and the sintering reaction. For example, as will be shown in the examples below, the ferrite production reaction, which required a sintering temperature of about 1250°C in the case of the conventional method, was heated to 1100°C in the case of the present invention.
Even if sintering is carried out at a certain temperature, the growth of ferrite crystals will occur sufficiently, making it possible to produce spherical ferrite powder that is dense, strong, and has good fluidity.
Note that such an effect occurs even when polyvinyl alcohol is added alone (without the addition of a surfactant), but in this case, the resulting spherical ferrite powder is inferior to the product of the present invention in terms of density and fluidity.
本発明法による場合には、従来のように二段階
焼成を必要とすることなく一段焼成で良品質のフ
エライト球状粉が得られるから一次焼成工程と粉
砕工程が省略できる点で製造工程が簡略化するこ
とはもとより、焼成温度も低くできる点でも極め
て有利である。そして、造粒工程においてもスラ
リーの固体濃度を高くすることができるので、噴
霧乾燥時での時間当たりの処理量が多くなると共
に乾燥熱源も軽減するという効果も得られる。ま
た基本的なことであるが、本発明法によつて得ら
れるフエライト球状粉は従来法によるものと比べ
ても優とも劣らない緻密性と強度を持ち、静電写
真用のトナーキヤリヤーとして必要な均一球状性
と流動性を兼備した良品質なものが得られる。 In the case of the method of the present invention, high-quality spherical ferrite powder can be obtained in one step of firing without requiring two-step firing as in the conventional method, which simplifies the manufacturing process in that the primary firing and crushing steps can be omitted. It is extremely advantageous not only in that the firing temperature can be lowered. Furthermore, since the solid concentration of the slurry can be increased in the granulation step, the amount of processing per hour during spray drying can be increased, and the drying heat source can also be reduced. Moreover, the spherical ferrite powder obtained by the method of the present invention has a density and strength comparable to those obtained by the conventional method, and is necessary as a toner carrier for electrostatic photography. Good quality products with uniform sphericity and fluidity can be obtained.
以下、本発明法の代表的な実施例並びに比較例
を挙げる。 Typical examples and comparative examples of the method of the present invention are listed below.
例 １
（造粒までの実施例その一）
モル百分率において、NiO；25％、ZnO；20
％、Fe2O3；55％、を秤量した。このフエライト
形成金属酸化物混合粉に、水と、ポバールPVA
−105（クラレ株式会社より市販のポリビニールア
ルコール）を該酸化混合粉当たり1.0重量％と、
ポイズ530（花王石鹸株式会社より市販のボリカル
ボン酸のナトリウム塩）を該酸化物混合粉当たり
0.3重量％と、を加え、ボールミルで１時間混合
撹拌してスラリーを作つた。スラーの固体濃度は
72％、粘度は600cpであつた。このスラリーをデ
イスク型のスプレードライヤーで噴霧乾燥してビ
ーズを造粒した。得られた造粒ビーズは形状が球
形で空洞は見られず良く締まつており、均一であ
り、その見掛密度（JIS−Ｚ−2504の測定法によ
る。以下同じ）は1.39ｇ／c.c.であつた。Example 1 (Example 1 up to granulation) In molar percentage, NiO: 25%, ZnO: 20
%, Fe 2 O 3 ; 55%. Add water and poval PVA to this ferrite-forming metal oxide mixed powder.
-105 (polyvinyl alcohol commercially available from Kuraray Co., Ltd.) at 1.0% by weight based on the oxidized mixed powder,
Poise 530 (sodium salt of polycarboxylic acid commercially available from Kao Soap Co., Ltd.) was added per oxide mixed powder.
0.3% by weight was added and mixed and stirred in a ball mill for 1 hour to prepare a slurry. The solid concentration of the slur is
72%, and the viscosity was 600 cp. This slurry was spray-dried using a disk-type spray dryer to granulate beads. The obtained granulated beads were spherical in shape with no visible cavities, well compacted, and uniform, and their apparent density (according to the measurement method of JIS-Z-2504; the same applies hereinafter) was 1.39 g/cc. It was hot.
なお、スプレードライヤーの運転はスムースで
順調であり、その処理量は金属酸化物換算で12
Kg／時であつた。 The spray dryer is operating smoothly and smoothly, and the processing amount is 12% in terms of metal oxides.
Kg/hour.
例 ２
（造粒までの実施例その二）
例１と同じフエライト形成金属酸化物混合粉を
使用し、これに、水と、例１と同じくポバール
PVA−105を混合粉当たり0.5重量％と、サンエ
キス−SCP（山陽国策パルプ株式会社より市販の
リグニンスルホン酸のカルシウム塩）を該混合粉
当たり0.8重量％と、を加え、ボールミルで１時
間混合撹拌してスラリーを作つた。スラリーの固
体濃度は68％、粘度は1100cpであつた。このス
ラリーを例１と同じスプレードライヤーで噴霧乾
燥してビーズを造粒した。得られた造粒ビーズは
形状が球形で空洞は見られず良く締まつており、
均一であり、その見掛密度は1.33ｇ／c.c.であつ
た。Example 2 (Example 2 up to granulation) Using the same ferrite-forming metal oxide mixed powder as in Example 1, add water and poval as in Example 1.
Add 0.5% by weight of PVA-105 to the mixed powder and 0.8% by weight of Sunextract-SCP (calcium salt of lignin sulfonic acid commercially available from Sanyo Kokusaku Pulp Co., Ltd.) to the mixed powder, and mix for 1 hour in a ball mill. A slurry was made by stirring. The solids concentration of the slurry was 68% and the viscosity was 1100 cp. This slurry was spray dried using the same spray dryer as in Example 1 to granulate beads. The resulting granulated beads were spherical in shape, with no cavities observed, and were well compacted.
It was uniform and its apparent density was 1.33 g/cc.
なお、スプレードライヤーの運転はスムーズで
順調であり、その処理量は金属酸化物換算で11
Kg／時であつた。 The spray dryer operates smoothly and smoothly, and the processing amount is 11% in terms of metal oxides.
Kg/hour.
例 ３
（造粒までの比較例その一）
例１と同じフエライト形成金属酸化物混合粉を
使用し、これに、水と、ポバールPVA−105を混
合粉当たり1.0重量％と、を加え、ボールミルで
１時間混合撹拌してスラリーを作つた。スラリー
の固体濃度は55％、粘度は2700cpであつた。こ
のスラリーを例１と同じスプレードライヤーで噴
霧乾燥してビーズを造粒した。得られた造粒ビー
ズは形状は球形であつたが空洞が多く見られ、締
まりも不足しており、不均一であつた。そしてそ
の見掛密度は0.98ｇ／c.c.であつた。Example 3 (Comparative example up to granulation, part 1) Using the same ferrite-forming metal oxide mixed powder as in Example 1, water and 1.0% by weight of Poval PVA-105 per mixed powder were added, and ball milling was carried out. A slurry was prepared by mixing and stirring for 1 hour. The solids concentration of the slurry was 55% and the viscosity was 2700 cp. This slurry was spray dried using the same spray dryer as in Example 1 to granulate beads. Although the obtained granulated beads were spherical in shape, they had many cavities, were insufficiently compacted, and were non-uniform. Its apparent density was 0.98 g/cc.
本例の場合にはスプレードライヤーの運転中に
おいてアトマイザーの目詰まりが時々発生したの
で運転を休止して修復する必要があり、その処理
量は金属酸化物換算で６Kg／時であつた。 In the case of this example, the atomizer sometimes became clogged while the spray dryer was in operation, so it was necessary to stop the operation and repair it, and the throughput was 6 kg/hour in terms of metal oxides.
例 ４
（造粒までの比較例その二）
例１と同じフエライト形成金属酸化物混合粉を
使用し、これに、水だけを加え、ボールミルで１
時間混合撹拌してスラリーを作つた。スラリーの
固体濃度は58％、粘度は2300cpであつた。この
スラリーを例１と同じスプレードライヤーで噴霧
乾燥してビーズを造粒した。得られた造粒ビーズ
は例３よりも空洞は少ないものであつたが締まり
が不足して強度が弱いものであり、その見掛密度
は0.95ｇ／c.c.であつた。Example 4 (Comparative example 2 up to granulation) Using the same ferrite-forming metal oxide mixed powder as in Example 1, add only water to it, and mill it in a ball mill.
A slurry was prepared by mixing and stirring for hours. The solids concentration of the slurry was 58% and the viscosity was 2300 cp. This slurry was spray dried using the same spray dryer as in Example 1 to granulate beads. The resulting granulated beads had fewer cavities than Example 3, but were insufficiently compact and had weak strength, and the apparent density was 0.95 g/cc.
例 ５
（焼結の実施例その一）
例１で得られたビーズを82〜131μに篩分けし
た後、酸素濃度が0.1％以下の窒素ガス雰囲気中
で1100℃で6Hr焼成したところ、一様に良く焼結
し表面結晶が成長したフエライト球状粉が得られ
た。このフエライト球状粉の見掛密度は2.52ｇ／
c.c.で、流動度（JIS−Ｚ−2502の測定法による、
以下同じ）は26.2秒／50ｇであつた。また、飽和
磁化は72emu／ｇであつた。Example 5 (Sintering Example No. 1) The beads obtained in Example 1 were sieved to 82 to 131μ, and then fired at 1100℃ for 6 hours in a nitrogen gas atmosphere with an oxygen concentration of 0.1% or less. A spherical ferrite powder was obtained which was well sintered and had surface crystals grown. The apparent density of this ferrite spherical powder is 2.52g/
cc, flow rate (according to JIS-Z-2502 measurement method,
) was 26.2 seconds/50g. Moreover, the saturation magnetization was 72 emu/g.
例 ６
（焼結の実施例その二）
例２で得られたビーズを82〜131μに篩分けし
た後、酸素濃度が0.2％以下の窒素ガス雰囲気中
で1100℃で6Hr焼成したところ、一様に良く焼結
し表面結晶が成長したフエライト球状粉が得られ
た。このフエライト球状粉の見掛密度は2.56ｇ／
c.c.で、流動度は25.8秒／50ｇであつた。また、飽
和磁化は72emu／ｇであつた。Example 6 (Second Sintering Example) The beads obtained in Example 2 were sieved to 82 to 131 μm, and then fired at 1100°C for 6 hours in a nitrogen gas atmosphere with an oxygen concentration of 0.2% or less. A spherical ferrite powder was obtained which was well sintered and had surface crystals grown. The apparent density of this spherical ferrite powder is 2.56g/
cc, and the flow rate was 25.8 seconds/50g. Moreover, the saturation magnetization was 72 emu/g.
例 ７
（焼結の比較例その一）
例１で得られたビーズを82〜131μに篩分けし
た後、酸素濃度が５％の窒素ガス雰囲気中で1100
℃で6Hr焼成したところ、焼結不足で表面結晶が
小さいフエライト球状粉が得られた。このフエラ
イト球状粉の見掛密度は2.12ｇ／c.c.で、流動度は
33.2秒／50ｇであつた。また、飽和磁化は
65emu／ｇであつた。Example 7 (Comparative example of sintering, part 1) After sieving the beads obtained in Example 1 to 82 to 131μ, they were sieved to 1100 μm in a nitrogen gas atmosphere with an oxygen concentration of 5%.
When fired at ℃ for 6 hours, spherical ferrite powder with small surface crystals due to insufficient sintering was obtained. The apparent density of this ferrite spherical powder is 2.12 g/cc, and the fluidity is
It was 33.2 seconds/50g. Also, the saturation magnetization is
It was 65emu/g.
例 ８
（造粒比較品の焼結）
例３（造粒の比較例１）で得られたビーズを82
〜131μ篩分けした後、酸素濃度が0.1％以下の窒
素ガス雰囲気中で1100℃で6Hr焼成したところ、
良く焼結して表面結晶も成長していたが空洞や孔
が見られるフエライト球状粉が得られた。これ
は、造粒ビーズ自身が空洞の多いものでありかつ
その形状が不均一であつたことによる。このフエ
ライト粉の見掛密度は2.22ｇ／c.c.で、流動度は
30.9秒／50ｇであつた。また、飽和磁化は
71emu／ｇであつた。Example 8 (Sintering of granulated comparative product) The beads obtained in Example 3 (granulated comparative example 1) were
After sieving through a ~131μ sieve, it was baked at 1100℃ for 6 hours in a nitrogen gas atmosphere with an oxygen concentration of 0.1% or less.
A spherical ferrite powder was obtained which was well sintered and surface crystals had grown, but cavities and pores were observed. This is because the granulated beads themselves had many cavities and were non-uniform in shape. The apparent density of this ferrite powder is 2.22g/cc, and the fluidity is
It was 30.9 seconds/50g. Also, the saturation magnetization is
It was 71emu/g.
例 ９
（造粒比較品の焼結）
例４（造粒の比較例２）で得られたビーズを82
〜131μに篩分けした後、酸素濃度が0.1％以下の
窒素ガス雰囲気中で1100℃で6Hr焼成したとこ
ろ、焼結不十分で表面結晶の微細なフエライト球
状物が得られた。このフエライト粉の見掛密度は
1.95ｇ／c.c.で、流動度は35.9秒／50ｇであつた。
また、飽和磁化は67emu／ｇであつた。Example 9 (Sintering of granulated comparative product) The beads obtained in Example 4 (granulated comparative example 2) were
After being sieved to ~131μ, it was fired at 1100°C for 6 hours in a nitrogen gas atmosphere with an oxygen concentration of 0.1% or less, resulting in insufficient sintering and ferrite spheres with fine surface crystals. The apparent density of this ferrite powder is
The flow rate was 35.9 seconds/50g at 1.95g/cc.
Moreover, the saturation magnetization was 67 emu/g.
以上の例７、８、９のフエライト球状粉は静電
写真用キヤリヤーとしては不適なものであつた
が、例５および例６で得られたフエライト球状粉
は、これを静電写真用キヤリヤーとして使用した
ところ100000〜120000枚のコピーをしても鮮明か
つ安定した画像が維持されるものであつた。これ
は、従来の二段階焼成法で得られたフエライト球
状粉キヤリヤーと同等以上の耐久性を有すること
を示している。 The ferrite spherical powders of Examples 7, 8, and 9 above were unsuitable for use as electrostatic photographic carriers, but the ferrite spherical powders obtained in Examples 5 and 6 could be used as electrostatic photographic carriers. When used, clear and stable images were maintained even after 100,000 to 120,000 copies were made. This shows that it has durability equal to or higher than that of the ferrite spherical powder carrier obtained by the conventional two-step firing method.
Claims (1)
成することなく水に分散させ、このスラリーを噴
霧乾燥して実質的に球状のビーズとし、このビー
ズをフエライトに焼成して球状フエライト粒子を
得るにあたり、前記スラリーを形成するさいに該
金属酸化物粉に対する重量基準で0.1〜３重量％
のポリビニールアルコールと、0.01〜５重量％の
ポリカルボン酸またはリグニンスルホン酸のナト
リウム塩、アンモニウム塩またはカルシウム塩の
いづれか一種または二種以上とを添加して該ビー
ズに造粒し、このビーズをフエライトに焼成する
さいに酸素濃度が１％以下の実質上非酸化性雰囲
気下で焼成することを特徴とするフエライト球状
粉の製造法。1. Dispersing metal oxide powder with a ferrite-forming composition in water without pre-calcination, spray drying this slurry to form substantially spherical beads, and firing the beads into ferrite to obtain spherical ferrite particles. 0.1 to 3% by weight based on the metal oxide powder when forming the slurry
of polyvinyl alcohol and 0.01 to 5% by weight of one or more of sodium salt, ammonium salt, or calcium salt of polycarboxylic acid or lignin sulfonic acid are added to the beads, and the beads are granulated. A method for producing spherical ferrite powder, which is characterized in that the ferrite is fired in a substantially non-oxidizing atmosphere with an oxygen concentration of 1% or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58167563A JPS6060930A (en) | 1983-09-13 | 1983-09-13 | Manufacture of spherical ferrite powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58167563A JPS6060930A (en) | 1983-09-13 | 1983-09-13 | Manufacture of spherical ferrite powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6060930A JPS6060930A (en) | 1985-04-08 |
| JPS6310096B2 true JPS6310096B2 (en) | 1988-03-03 |
Family
ID=15852044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58167563A Granted JPS6060930A (en) | 1983-09-13 | 1983-09-13 | Manufacture of spherical ferrite powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6060930A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6177625A (en) * | 1984-09-21 | 1986-04-21 | Taiyo Yuden Co Ltd | Manufacture of ferrite magnetic powdery body for magnetic paint |
| WO1993004408A1 (en) * | 1991-08-16 | 1993-03-04 | Eastman Kodak Company | Ferrite green beads and method of producing carrier particles |
| US7144670B2 (en) * | 2002-03-26 | 2006-12-05 | Powertech Co., Ltd. | Carrier for electrophotographic developer and process of producing the same |
| JP5366069B2 (en) * | 2008-03-26 | 2013-12-11 | パウダーテック株式会社 | Ferrite particles and manufacturing method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5090996A (en) * | 1973-12-12 | 1975-07-21 | ||
| JPS5256536A (en) * | 1975-10-29 | 1977-05-10 | Xerox Corp | Non humidityysensitive electrophotography carrier material made of ferrite and method of producing |
| JPS5315040A (en) * | 1976-07-28 | 1978-02-10 | Toshiba Corp | Automatic unit |
-
1983
- 1983-09-13 JP JP58167563A patent/JPS6060930A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5090996A (en) * | 1973-12-12 | 1975-07-21 | ||
| JPS5256536A (en) * | 1975-10-29 | 1977-05-10 | Xerox Corp | Non humidityysensitive electrophotography carrier material made of ferrite and method of producing |
| JPS5315040A (en) * | 1976-07-28 | 1978-02-10 | Toshiba Corp | Automatic unit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6060930A (en) | 1985-04-08 |
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