JPH058139B2 - - Google Patents
Info
- Publication number
- JPH058139B2 JPH058139B2 JP62050838A JP5083887A JPH058139B2 JP H058139 B2 JPH058139 B2 JP H058139B2 JP 62050838 A JP62050838 A JP 62050838A JP 5083887 A JP5083887 A JP 5083887A JP H058139 B2 JPH058139 B2 JP H058139B2
- Authority
- JP
- Japan
- Prior art keywords
- magnesia
- particles
- primary particles
- granulation
- weight
- 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 - Lifetime
Links
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 53
- 239000000395 magnesium oxide Substances 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 24
- 239000011164 primary particle Substances 0.000 claims description 22
- 239000011163 secondary particle Substances 0.000 claims description 17
- 238000005469 granulation Methods 0.000 claims description 10
- 230000003179 granulation Effects 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000001694 spray drying Methods 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 4
- 238000010298 pulverizing process Methods 0.000 claims description 4
- 235000002911 Salvia sclarea Nutrition 0.000 claims 1
- 244000182022 Salvia sclarea Species 0.000 claims 1
- 239000002245 particle Substances 0.000 description 14
- 229910052573 porcelain Inorganic materials 0.000 description 10
- 239000004094 surface-active agent Substances 0.000 description 8
- 238000000465 moulding Methods 0.000 description 7
- 239000007864 aqueous solution Substances 0.000 description 6
- 238000005245 sintering Methods 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 230000029087 digestion Effects 0.000 description 4
- 235000019441 ethanol Nutrition 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- 239000003125 aqueous solvent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012776 electronic material Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 2
- 239000000347 magnesium hydroxide Substances 0.000 description 2
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 239000002736 nonionic surfactant Substances 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 239000005456 alcohol based solvent Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000011361 granulated particle Substances 0.000 description 1
- 230000000887 hydrating effect Effects 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Description
［産業上の利用分野］
本発明はマグネシア（MgO）の造粒方法に係
り、特に電子材料焼成用又は金属溶解用のルツ
ボ、サヤ、ボード等に使用される各種マグネシア
磁器等の製造に好適なマグネシアの造粒方法に関
する。
［従来の技術］
マグネシア磁器は、電子材料焼成用又は金属溶
解用のルツボやサヤ、ボード等に広く用いられて
いる。
従来、マグネシア磁器の製造工程における成形
方法としては、ラバープレス法、金型プレス法が
主として採用されている。これらの成形方法にお
いては、粒子の流動性が極めて重要であることか
ら、成形にあたつては、まず、電融マグネシア又
はデツドバーンクリンカー状マグネシア粒子原料
を微粉砕して１次粒子とし、この１次粒子から２
次粒子を形成させて、成形原料としている。２次
粒子の形成にあたつては、マグネシアは水和性物
質であることから、１次粒子をアルコール系溶液
に懸濁してスラリー状とし、これをスプレードラ
イ法によつて球状化して２次粒子としている。
このような従来の成形方法では成形された成形
体は、通常の場合1400〜1700℃で焼成して磁器が
製造されるが、その際、焼結性を高めるために
B2O3、CaO、SiO2のような焼結助剤を添加して
焼成するのが一般的である。
［発明が解決しようとする問題点］
このような従来の方法では、２次粒子の造粒に
あたり、電融マグネシア又はデツドバーンクリン
カー状マグネシア粒子等のマグネシア原料の水和
を防止するために、懸濁溶媒がアルコール系等の
非水溶媒に限定される。このため、造粒に要する
費用が高く、また、アルコール類は環境を汚染す
るおそれがあるために、公害防止設備にも膨大な
費用が必要とされ、製品が高コストとなるという
問題がある。
［問題点を解決するための手段］
本発明は、電融又は死焼マグネシアを微粉砕し
て１次粒子とし、該１次粒子から２次粒子を形成
する方法において、原料の粉砕工程で水を添加し
て１次粒子の表面を５〜15重量％の部分消化量と
なるように部分消化し、得られた１次粒子に水を
加えてスラリー状とし、次いで造粒及び乾燥する
ことにより２次粒子を形成することを特徴とする
マグネシアの造粒方法を要旨とする。
以下、本発明を詳細に説明する。
本発明においては、まず、電融又は死焼（デツ
ドバーンクリンカー状）マグネシアを好ましくは
粒径20μｍ以下程度に微粉砕して１次粒子を得
る。
本発明においては、電融又は死焼マグネシアを
粉砕するにあたり、水、好ましくは濃度0.1〜2.0
重量％の界面活性剤を含有する水溶液を添加す
る。水の添加により、マグネシアが消化し、得ら
れる１次粒子の表面に部分消化層が形成される。
この部分消化層の形成により、焼結性の改善が図
れるが、部分消化層があまりに大きいと、逆に焼
結性が損なわれることとなる。従つて、水又は界
面活性剤含有水溶液の添加量は、得られる１次粒
子表面の部分消化割合が５〜15重量％となるよう
な量とする。この消化割合が５重量％未満では、
消化層が粒子表面に均一に形成されず、焼結性の
改善効果が低く、15重量％を越えると焼結時に成
形体が割れたり、焼結品の密度が上がらないなど
の問題点が生じることがある。
粉砕により得られた１次粒子は、次いで造粒し
て２次粒子を形成させるが、本発明においては、
造粒にあたり、１次粒子を水又は0.1〜2.0重量％
濃度の界面活性剤含有水溶液に懸濁してスラリー
とし、これを造粒、乾燥する。
造粒、乾燥方法としては、スプレードライヤー
によるスプレードライ方式を採用するのが有利で
ある。勿論、本発明においては、造粒方法はスプ
レードライ方式に限定されるものではなく、流動
層方式などで前記の部分消化や造粒も可能であ
る。
このような造粒、乾燥により、好ましくは粒径
30〜100μｍ程度に球状化された、流動性に富み、
成形性に優れた２次粒子が形成される。
なお、本発明で用いられる界面活性剤として
は、特に制限はないが、一般には、エーテル型、
エステル型、その他のノニオン系界面活性剤等が
用いられる。
このようにして得られた２次粒子を成形し、こ
の成形体を焼結することにより磁器を製造するこ
とができる。
なお、この磁器の製造にあたり、焼結助剤を用
いても良いが、本発明で造粒された粒子は極めて
焼結性に優れるため、焼結助剤等は特に必要とさ
れない。
［作用］
本発明のマグネシアの造粒方法はアルコール等
の非水溶媒が不要であるため、低コストで実施で
き、しかも公害防止設備等も不要である。しかし
て、本発明の方法により、電融又は死焼マグネシ
アの１次粒子を表面を５〜15重量％の部分消化量
となるように部分消化することにより、流動性の
良好な２次粒子が造粒される。しかも、この２次
粒子は、極めて焼結性に優れ、焼結粒子の粒界も
きわめて小さく、良く焼結する。この理由の詳細
は明らかではないが、本発明で得られる２次粒子
は、マグネシア微粒子の表面に水酸化マグネシウ
ム層が均一に被覆された状態にあり、単に、マグ
ネシアに水酸化マグネシウムを混合した状態とは
全く異なる状態となつていることによるものと推
測される。
このように流動性及び焼結性に優れた２次粒子
を用いると、緻密質で極めて強度の大きな磁器体
を容易に得ることができる。
［実施例］
以下、実施例について説明する。
なお、以下の実施例において「％」は「重量
％」を示す。
実施例１、２、比較例１
粒径0.5mmの電融マグネシア100重量部に0.5％
濃度の界面活性剤（エステル型ノニオン系界面活
性剤）を含有した水溶液を１次粒子の部分消化量
が５％（実施例１）、15％（実施例２）、30％（比
較例１）となるように添加し、メデア撹拌型粉砕
機で粉砕して、粒径20μｍ以下の電融マグネイア
１次粒子を製造した。
次に、この１次粒子100重量部にそれぞれ前記
界面活性剤水溶液を45重量部加えてスラリー状と
し、スプレードライ法によつて第１表に示す粒径
の２次造粒粒子を得た。この２枚粒子を用いて金
型プレス法により成形し、第１表に示す温度で焼
結して、マグネシア磁器を製造した。
得られたマグネシア磁器の密度を第１表に示
す。
[Industrial Application Field] The present invention relates to a method for granulating magnesia (MgO), and is particularly suitable for manufacturing various magnesia porcelains used for crucibles, sheaths, boards, etc. for firing electronic materials or melting metals. This invention relates to a method for granulating magnesia. [Prior Art] Magnesia porcelain is widely used for crucibles, sheaths, boards, etc. for firing electronic materials or melting metals. Conventionally, as a molding method in the manufacturing process of magnesia porcelain, a rubber press method and a mold press method have been mainly adopted. In these molding methods, the fluidity of the particles is extremely important, so in molding, first, the raw material for fused magnesia or dead burn linker-like magnesia particles is finely pulverized to form primary particles. 2 from the primary particle
The secondary particles are formed and used as a molding raw material. To form secondary particles, since magnesia is a hydrating substance, the primary particles are suspended in an alcohol solution to form a slurry, which is then spheroidized by a spray drying method to form secondary particles. It is made into particles. In such conventional molding methods, the molded body is usually fired at 1400 to 1700°C to produce porcelain, but at that time, in order to improve sinterability,
It is common to add a sintering aid such as B 2 O 3 , CaO, or SiO 2 to the sintering process. [Problems to be Solved by the Invention] In such conventional methods, in order to prevent hydration of magnesia raw materials such as fused magnesia or dead burn clinker-like magnesia particles, when granulating secondary particles, The cloudy solvent is limited to non-aqueous solvents such as alcohol-based solvents. Therefore, the cost required for granulation is high, and since alcohols may pollute the environment, a huge amount of cost is required for pollution prevention equipment, resulting in a problem that the product is expensive. [Means for Solving the Problems] The present invention provides a method in which electrofused or dead-burned magnesia is finely pulverized into primary particles and secondary particles are formed from the primary particles, in which water is not used in the raw material pulverization step. The surface of the primary particles is partially digested to a partial digested amount of 5 to 15% by weight, water is added to the obtained primary particles to form a slurry, and then granulated and dried. The gist of the present invention is a method for granulating magnesia, which is characterized by forming secondary particles. The present invention will be explained in detail below. In the present invention, first, electromelted or dead burnt (dead burnt clinker-like) magnesia is pulverized preferably to a particle size of about 20 μm or less to obtain primary particles. In the present invention, water, preferably at a concentration of 0.1 to 2.0, is used to crush electrofused or dead-burned magnesia.
An aqueous solution containing % by weight surfactant is added. By adding water, magnesia is digested and a partially digested layer is formed on the surface of the resulting primary particles.
By forming this partially digested layer, sinterability can be improved, but if the partially digested layer is too large, the sinterability will be impaired. Therefore, the amount of water or surfactant-containing aqueous solution added is such that the partial digestion rate of the surface of the resulting primary particles is 5 to 15% by weight. If this digestion rate is less than 5% by weight,
The digestion layer is not formed uniformly on the particle surface, and the effect of improving sinterability is low.If the content exceeds 15% by weight, problems such as cracking of the compact during sintering and failure to increase the density of the sintered product occur. Sometimes. The primary particles obtained by pulverization are then granulated to form secondary particles, but in the present invention,
During granulation, primary particles are mixed with water or 0.1 to 2.0% by weight.
It is suspended in a surfactant-containing aqueous solution of a certain concentration to form a slurry, which is then granulated and dried. As the granulation and drying method, it is advantageous to use a spray drying method using a spray dryer. Of course, in the present invention, the granulation method is not limited to the spray drying method, but the above-mentioned partial digestion and granulation can also be performed using a fluidized bed method or the like. Through such granulation and drying, the particle size is preferably reduced.
Spheroidized to about 30 to 100 μm, highly fluid,
Secondary particles with excellent moldability are formed. The surfactant used in the present invention is not particularly limited, but in general, ether type,
Ester type surfactants, other nonionic surfactants, etc. are used. Porcelain can be manufactured by molding the secondary particles thus obtained and sintering the molded body. Note that a sintering aid may be used in the production of this porcelain, but since the particles granulated in the present invention have extremely excellent sinterability, a sintering aid or the like is not particularly required. [Function] Since the magnesia granulation method of the present invention does not require a non-aqueous solvent such as alcohol, it can be carried out at low cost and does not require any pollution prevention equipment. According to the method of the present invention, secondary particles with good fluidity can be obtained by partially digesting the surface of primary particles of electrofused or dead-burned magnesia to a partial digested amount of 5 to 15% by weight. Granulated. Moreover, these secondary particles have extremely excellent sinterability, the grain boundaries of the sintered particles are extremely small, and they sinter well. The details of this reason are not clear, but the secondary particles obtained by the present invention have a magnesium hydroxide layer uniformly coated on the surface of magnesia fine particles, and are simply a mixture of magnesia and magnesium hydroxide. It is presumed that this is due to the fact that the situation is completely different from the previous one. By using secondary particles with such excellent fluidity and sinterability, a dense and extremely strong porcelain body can be easily obtained. [Example] Examples will be described below. In addition, in the following examples, "%" indicates "weight %". Examples 1 and 2, Comparative Example 1 0.5% in 100 parts by weight of electrofused magnesia with a particle size of 0.5 mm
An aqueous solution containing a surfactant (ester-type nonionic surfactant) at a concentration of 5% (Example 1), 15% (Example 2), and 30% (Comparative Example 1) of primary particles The powder was added in such a manner as to be pulverized using a Medea stirring type pulverizer to produce fused magneia primary particles having a particle size of 20 μm or less. Next, 45 parts by weight of the surfactant aqueous solution was added to each of 100 parts by weight of the primary particles to form a slurry, and secondary granulated particles having the particle sizes shown in Table 1 were obtained by spray drying. These two particles were molded by a mold press method and sintered at the temperatures shown in Table 1 to produce magnesia porcelain. Table 1 shows the density of the obtained magnesia porcelain.
【表】
比較例 ２
実施例１において、１次粒子の製造工程におい
て界面活性剤の水溶液を代わりにアルコール（エ
チルアルコール）を用いたこと、及びスプレード
ライを行うに際しさらに該アルコールを25重量部
加えたこと以外は同様にして平均粒径80μｍに造
粒して成形を行い、焼結した。得られた磁器の密
度の測定結果は第２表に示す通りであつた。[Table] Comparative Example 2 In Example 1, alcohol (ethyl alcohol) was used instead of the aqueous solution of surfactant in the primary particle manufacturing process, and 25 parts by weight of the alcohol was added when performing spray drying. Except for the above, granules were granulated to an average particle size of 80 μm, molded, and sintered. The measurement results of the density of the obtained porcelain were as shown in Table 2.
【表】
第１表及び第２表より、本発明の方法により造
粒された２次粒子を用いると、緻密で高特性な磁
器が得られることが明らかである。
なお、実施例１、２において、木材の流動性は
著しく良好で、成形作業が極めて容易であつた。
［発明の効果］
以上詳述した通り、本発明のマグネシアの造粒
方法によれば、流動性及び焼結性に優れた、マグ
ネシア２次粒子を低コストで容易かつ効率的に造
粒することができる。[Table] From Tables 1 and 2, it is clear that when the secondary particles granulated by the method of the present invention are used, dense porcelain with high characteristics can be obtained. In addition, in Examples 1 and 2, the fluidity of the wood was extremely good, and the molding operation was extremely easy. [Effects of the Invention] As detailed above, according to the magnesia granulation method of the present invention, magnesia secondary particles with excellent fluidity and sinterability can be easily and efficiently granulated at low cost. I can do it.
Claims (1)
子とし、該１次粒子から２次粒子を形成する方法
において、原料の粉砕工程で水を添加して１次粒
子の表面を５〜15重量％の部分消化量となるよう
に部分消化し、得られた１次粒子に水を加えてク
ラリー状とし、次いで造粒及び乾燥することによ
り２次粒子を形成することを特徴とするマグネシ
アの造粒方法。 ２ 造粒及び乾燥はスプレードライ法によること
を特徴とする特許請求の範囲第１項に記載の方
法。[Claims] 1. In a method of finely pulverizing electrofused or dead-burned magnesia to form primary particles and forming secondary particles from the primary particles, water is added in the raw material pulverizing process to form the primary particles. The surface of the primary particles is partially digested to a partial digested amount of 5 to 15% by weight, water is added to the resulting primary particles to form a clary, and the secondary particles are then formed by granulation and drying. A method for granulating magnesia characterized by: 2. The method according to claim 1, wherein the granulation and drying are performed by a spray drying method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62050838A JPS63218534A (en) | 1987-03-05 | 1987-03-05 | Method of granulating magnesia raw material and manufacture of magnesia-base ceramics |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62050838A JPS63218534A (en) | 1987-03-05 | 1987-03-05 | Method of granulating magnesia raw material and manufacture of magnesia-base ceramics |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4225626A Division JPH0672043B2 (en) | 1992-08-25 | 1992-08-25 | Manufacturing method of magnesia porcelain |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63218534A JPS63218534A (en) | 1988-09-12 |
| JPH058139B2 true JPH058139B2 (en) | 1993-02-01 |
Family
ID=12869885
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62050838A Granted JPS63218534A (en) | 1987-03-05 | 1987-03-05 | Method of granulating magnesia raw material and manufacture of magnesia-base ceramics |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63218534A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5091609A (en) * | 1973-12-12 | 1975-07-22 | ||
| JPS5127685A (en) * | 1974-08-30 | 1976-03-08 | Fujitsu Ten Ltd | Teisokusokokikoyo no shasokusetsuteidenatsushutsuryokusochi |
| JPS5729433A (en) * | 1980-07-30 | 1982-02-17 | Seikosha Co Ltd | Manufacture of synthetic resin hand |
-
1987
- 1987-03-05 JP JP62050838A patent/JPS63218534A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5091609A (en) * | 1973-12-12 | 1975-07-22 | ||
| JPS5127685A (en) * | 1974-08-30 | 1976-03-08 | Fujitsu Ten Ltd | Teisokusokokikoyo no shasokusetsuteidenatsushutsuryokusochi |
| JPS5729433A (en) * | 1980-07-30 | 1982-02-17 | Seikosha Co Ltd | Manufacture of synthetic resin hand |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63218534A (en) | 1988-09-12 |
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