JPS6011219A - Manufacture of zinc silicate - Google Patents

Abstract

PURPOSE:To obtain fine-grained zinc silicate of high purity suitable for use as an additive for a nonlinear zinc oxide voltage resistor with high reproducibility by converting zinc ions into a specified zinc complex and reacting the complex with an aqueous soln. contg. silicate ions. CONSTITUTION:A ligand consisting of atoms such as C, H and N, e.g., ammonia or ethylenediamine is added to an aqueous soln. contg. zinc ions such as an aqueous soln. of zinc nitrate to convert all of the zinc ions in the soln. at 8- 12pH into a zinc complex which is not decomposed and does not cause precipitation, e.g., a zinc ammine complex. To the resulting soln. is added an aqueous soln. contg. silicate ions such as an aqueous soln. of sodium metasilicate, and they are stirred under heating to cause a reaction. A white precipitate produced by the reaction is separated by filtration, washed, and dried to obtain desired zinc silicate powder. This zinc silicate powder contains a small amount of trace impurity elements and has a small average particle size.

Description

【発明の詳細な説明】 この発明は、亜鉛イオン含有水溶液とケイ酸イオン含有
水溶液を混合してケイ酸亜鉛を製造する方法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing zinc silicate by mixing an aqueous solution containing zinc ions and an aqueous solution containing silicate ions.

ケイ酸亜鉛はケイ光体用の材料や酸化亜鉛電圧非直線抵
抗体の添加物として広く用いられている。Zinc silicate is widely used as a material for phosphors and as an additive in zinc oxide voltage nonlinear resistors.

ことに電圧非直線抵抗体の場合には、電圧非直線性や寿
命の改善のためには不可欠であるため、酸化亜鉛添加物
として安定した組成をもつ高純度のケイ酸亜鉛が要求さ
れる。ケイ酸亜鉛の合成は、通常酸化亜鉛と二酸化ケイ
素の粉末を混合して、１０００　Ｃ以上の高温で反応さ
せる方法がある（粉末合成法）０この方法では原料の純
度が直接生成物の純度となり、高純度の酸化亜鉛と二酸
化ケイ素を用意する必要がある。また、この粉末合成法
では、１ｏｏｏｒ：以上の高温で反応させるためケイ酸
亜鉛粒子が生長してその粒径が太き（なり、酸化亜鉛電
圧非直線抵抗体への添加に際し粉砕混合を十分に行わな
いと抵抗体内でのケイ酸亜鉛の分布が不均一になり、高
エネルギーサージにより熱的素子破壊が起こるなどの欠
点があった。Particularly in the case of voltage nonlinear resistors, high purity zinc silicate with a stable composition is required as a zinc oxide additive since it is essential for improving voltage nonlinearity and service life. Zinc silicate is usually synthesized by mixing powders of zinc oxide and silicon dioxide and reacting at a high temperature of 1000 C or higher (powder synthesis method). In this method, the purity of the raw materials directly affects the purity of the product. , it is necessary to prepare high-purity zinc oxide and silicon dioxide. In addition, in this powder synthesis method, since the reaction is carried out at a high temperature of 1 ooor or higher, the zinc silicate particles grow and their particle size becomes thick. If this was not done, the distribution of zinc silicate within the resistor would become uneven, resulting in drawbacks such as thermal element destruction due to high energy surges.

他の方法としては、亜鉛イオン水溶液とケイ酸イオン水
溶液を溶液混合し、ケイ酸亜鉛を沈殿させる方法がある
。しかし、この従来の溶液混合法では、弱酸性となって
いる亜鉛イオン水溶液（亜鉛化合物の加水分解により弱
酸性となる）にアルカリ性となっているケイ酸イオン水
溶液を加えると（またはその逆の場合においても）、亜
鉛の水酸化物がケイ酸亜鉛と同時に沈殿する。この亜鉛
水酸化物の沈殿生成は亜鉛イオン濃度、ケイ酸イオン濃
度、溶液の温度、攪拌の状況等各種合成条件の違いによ
り変化するため、最終的沈殿物の構成元素比が変化し、
一定の質のケイ酸亜鉛を得るのは困難であるという欠点
があった。このため、酸化亜鉛電圧非直線抵抗体の特性
（例えば寿命）も安定しないという欠点がふった。Another method is to mix a zinc ion aqueous solution and a silicate ion aqueous solution to precipitate zinc silicate. However, in this conventional solution mixing method, when an alkaline silicate ion aqueous solution is added to a weakly acidic zinc ion aqueous solution (which becomes weakly acidic due to hydrolysis of the zinc compound) (or vice versa), ), zinc hydroxide precipitates simultaneously with zinc silicate. The formation of this zinc hydroxide precipitate changes depending on various synthesis conditions such as zinc ion concentration, silicate ion concentration, solution temperature, and stirring conditions, so the constituent element ratio of the final precipitate changes.
The drawback was that it was difficult to obtain zinc silicate of consistent quality. As a result, the characteristics (for example, life span) of the zinc oxide voltage nonlinear resistor were not stable.

この発明は上記のような従来のものの欠点を除去するた
めになされたもので、予め後の熱処理により除去可能な
Ｃ，Ｈ，Ｎ等より構成される配位子を亜鉛イオン水溶液
に加え、ｐｇ　がｆ　−／　Ｊの状態において溶液内の
亜鉛イオンをすべて安定な亜鉛錯体に変換しておき、ア
ルカリ性であるケイ酸イオン水溶液と混合することによ
って、亜鉛の水酸化物の沈殿を生成させることな（、化
学的に純粋で微細なケイ酸亜鉛を得ることを目的として
いる。上記条件を満足する配位子としてはアンモニア、
エチレンジアミン等が挙げられる。例えば亜鉛水溶液に
アンモニア水を加えると亜鉛アンミン錯体が生成する、 以上の反応を化学反応式で表わすと下記の通りである。This invention was made in order to eliminate the drawbacks of the conventional methods as described above. Ligands composed of C, H, N, etc., which can be removed by subsequent heat treatment, are added in advance to an aqueous zinc ion solution, and pg By converting all the zinc ions in the solution into stable zinc complexes in the state of f - / J and mixing them with an alkaline silicate ion aqueous solution, it is possible to prevent the formation of zinc hydroxide precipitates. (The purpose is to obtain chemically pure and fine zinc silicate. Ligands that satisfy the above conditions include ammonia,
Examples include ethylenediamine. For example, when aqueous ammonia is added to an aqueous zinc solution, a zinc ammine complex is formed. The above reaction can be expressed as a chemical reaction formula as follows.

従来溶液法 この発明の方法（アンモニアを用いた場合）を図に基い
て説明する。Conventional solution method The method of this invention (when ammonia is used) will be explained based on the drawings.

第１図及び第一図において、合成装置はビーカー／、滴
下ロートコ、リング３、スタンドダ、ホットプレート付
スターラー５１攪拌子６、亜鉛アンミン錯体水溶液？、
メタケイ酸ナトリウム水溶液ｇ、水を等からなる。1 and 1, the synthesis apparatus is a beaker/, a dropping funnel, a ring 3, a stander, a stirrer 51 with a hot plate, a stirring bar 6, and an aqueous solution of zinc ammine complex. ,
It consists of an aqueous solution of sodium metasilicate (g), water, etc.

以下、実施例に基いて本発明を説明する。The present invention will be explained below based on Examples.

実施例！ 本実施例に使用した装置の装置図を第７図に示した。Example! A diagram of the apparatus used in this example is shown in FIG.

硝酸亜鉛（Ｚｎ（Ｎｏ、）、　・ＡＨ，ｏ　）　／　＃
　ｔ、７　ＪＦ　を水３ｏｏｍｌｌ＜溶かした。この水
溶液を攪拌しながら、３０％アンモニア水１６θＩを除
々に加えた。アンモニア水を加えるに従ってまず白色沈
殿が生成したが、さらにアンモニア水を加えると次第に
沈殿は溶解し、最終的に無色透明の溶液となった。Zinc nitrate (Zn(No,), ・AH,o) / #
t, 7 JF was dissolved in 3 ooml of water. While stirring this aqueous solution, 16θI of 30% ammonia water was gradually added. As ammonia water was added, a white precipitate was first formed, but as more ammonia water was added, the precipitate gradually dissolved and finally became a colorless and transparent solution.

この溶液を７個の滴下ロートコに入れた。一方、メタケ
イ酸ナトリクム（Ｎａ、８ｉ０．　・９Ｈ，−０）　？
　／、　／　７７を水Ｊθθｄに溶かし、もう１個の滴
下ロートに入れた。ビーカー１ｔ／ＣｋθＯｗｌの水を
入れＳＯ〜６θＣで加熱攪拌し、雨滴下ロートからそれ
ぞれの水溶液をビーカー内の水りに滴下した。滴下速度
は両方とも１秒間にＯ，Ｓ〜を滴に設定した０滴下し始
めた直後はビーカー内の水溶液は無色透明でまったく変
化しなかったが、ｔｏ−ａｏｍ１滴下するに従って白濁
し、次第に白色沈殿が認められるようになった。滴下ロ
ート内の溶液をすべて加え終ってからもビーカーｌ中の
溶液をしばらく加熱攪拌を続けた。ビーカーｌ中の沈殿
を含む溶液を室温まで冷却した後、デカンテーションで
数回水洗した。次いで吸引Ｐ別を行った後、沈殿を数回
水洗し、乾燥後ケイ酸亜鉛粉末を得た。This solution was placed in seven dropping funnels. On the other hand, sodium metasilicate (Na, 8i0. 9H, -0)?
/, /77 was dissolved in water Jθθd and placed in another dropping funnel. A beaker was filled with 1 t/CkθOwl of water, heated and stirred at SO to 6θC, and each aqueous solution was dropped into the water tank in the beaker from a rain dropping funnel. The dropping speed was set to O, S~ per second for both cases. Immediately after starting dropping, the aqueous solution in the beaker was clear and colorless and did not change at all, but as one drop of to-aom was added, it became cloudy and gradually turned white. Precipitate was now observed. Even after all the solution in the dropping funnel had been added, the solution in beaker 1 was continued to be heated and stirred for a while. After cooling the solution containing the precipitate in beaker I to room temperature, it was washed with water several times by decantation. Next, after performing suction P separation, the precipitate was washed several times with water and dried to obtain zinc silicate powder.

実施側設 本実施例で使用した装置の装置図を第２図に示した。実
施例１と同様に調整した亜鉛アンミン錯体水溶液７をビ
ーカー／に入れ、また滴下ロートコには実施例１と同様
に調整したメタケイ酸ナトリウム水溶液ｇを入れた。亜
鉛アンミン錯体水溶液をｇｏ−ｂｏｃで加熱攪拌しなが
ら、メタケイ酸ナトリウム水溶液を滴下ロートコより滴
下した。Implementation side design A diagram of the apparatus used in this example is shown in FIG. Zinc ammine complex aqueous solution 7 prepared in the same manner as in Example 1 was placed in a beaker/, and sodium metasilicate aqueous solution g prepared in the same manner as in Example 1 was placed in the dropping funnel. While heating and stirring the zinc ammine complex aqueous solution using a go-boc, the sodium metasilicate aqueous solution was added dropwise from a dropping funnel.

その他の操作は実施例／と同様に行った。Other operations were performed in the same manner as in Example.

表に本発明の実施例１及び−により得られたケイ酸亜鉛
、従来の溶液合成法及び従来の粉末合成法で得られたケ
イ酸亜鉛のそれぞれの元素分析結果を示した。The table shows the elemental analysis results of the zinc silicates obtained in Examples 1 and - of the present invention, the conventional solution synthesis method, and the conventional powder synthesis method.

竹 ここで、沈殿により生成した粉末はＸ線回折法によると
アモルファスであるため、これをデ。０／３００Ｃまで
ほとんど変化していない。Bamboo Here, the powder produced by precipitation is amorphous according to X-ray diffraction, so it is decomposed. There is almost no change up to 0/300C.

表より明らかなように、含有微量元素の量は従来の粉末
合成法に比べて本発明により得られたケイ酸亜鉛の方が
少ない。また、本発明により得られたケイ酸亜鉛の再現
性も非常に良好であった。As is clear from the table, the amount of trace elements contained in the zinc silicate obtained by the present invention is smaller than that by the conventional powder synthesis method. Furthermore, the reproducibility of the zinc silicate obtained by the present invention was also very good.

また、粉末の相対平均粒径について従来の粉末合成法で
得られたケイ酸亜鉛を八〇〇として表わすと、本発明の
実施例／及びコではそれぞれ０．１！；。Also, regarding the relative average particle size of the powder, if the zinc silicate obtained by the conventional powder synthesis method is expressed as 800, then in Examples/and Co of the present invention, each is 0.1! ;.

ｏ、ｇｏとなり、従来のものより細かい粉末が得られる
。さらに、ケイ酸亜鉛の生成に要する温度も低くなり、
時間及びコストに対して有利である。o, go, and a finer powder than the conventional one can be obtained. Furthermore, the temperature required to produce zinc silicate is lower,
It is advantageous in terms of time and cost.

一方、従来の粉末合成法では不純物の含有量が多く粒径
も大きく、ケイ酸亜鉛の生成に要する温度も高い。また
、従来の溶液合成法では粒径が小さく、ケイ酸亜鉛の生
成に要する温度が低くなっているが、再現性が悪く、合
成の際における亜鉛イオン濃度、ケイ酸イオン濃度、溶
液の温度、攪性良く高純度のケイ酸亜鉛を得るのは困難
である。On the other hand, in the conventional powder synthesis method, the content of impurities is large, the particle size is large, and the temperature required to generate zinc silicate is high. In addition, although conventional solution synthesis methods have small particle sizes and low temperatures required to produce zinc silicate, reproducibility is poor, and the zinc ion concentration, silicate ion concentration, and solution temperature during synthesis are It is difficult to obtain highly pure zinc silicate with good stirrability.

実施例１と−では実施例／の方が含有微量元素の量が少
なくかつ粒径も細かいものが得られ、酸化亜鉛電圧非直
線抵抗体の添加用としては実施例Ｉの製法の方が望まし
い。これは実施例／では水デを媒体とする希薄濃度条件
下で亜鉛アンミン錯体とメタケイ酸ナトリウムとを反応
させたことによるもので、このような条件では沈殿生成
は徐々に進行し、不純物の吸着、吸蔵は極めて少な（な
り、純度の高いかつ極めて微細な粒度のケイ酸亜鉛が得
られる。一方、実施例−ではメタケイ酸イオンを亜鉛ア
ンミン錯体水溶液に滴下した場合、一時的弱所的にメタ
ケイ酸イオン濃度が高（かつ亜鉛アンミン錯体濃度も高
いため急激な沈殿生成が生じ、不純物の吸着、吸蔵が起
こるものと考えられる。Between Examples 1 and -, Example 1 had smaller amounts of trace elements and finer particle sizes, and the manufacturing method of Example I was preferable for use in adding zinc oxide voltage nonlinear resistors. . This is because the zinc ammine complex and sodium metasilicate were reacted under dilute concentration conditions using water as a medium in Example 1. Under these conditions, precipitation progressed gradually and impurities were adsorbed. , occlusion is extremely small (therefore, zinc silicate of high purity and extremely fine particle size is obtained.On the other hand, in Example--, when metasilicate ions are dropped into an aqueous solution of zinc ammine complex, metasilicate is temporarily weakly released). It is thought that because the acid ion concentration is high (and the zinc ammine complex concentration is also high), rapid precipitation occurs, leading to adsorption and occlusion of impurities.

なお、上記実施例ではアンモニア水を加えて亜鉛アンミ
ン錯体を合成する場合について説明したが、ｐＨがｇ〜
ノコの状態において分解せずまたは沈殿生成を起こさな
い亜鉛錯体で、熱処理により除去可能な配位子を含む他
の亜鉛錯体であってもよく、上記実施例と同様の効果を
奏する。また、上記実施例ではメタケイ酸ナトリウムと
硝酸亜鉛を使用した場合について説明したが、水を含む
種々の溶媒に可溶なその他のメタケイ酸塩、ケイ酸塩、
亜鉛化合物であってもよく、上記実施例と同様の効果を
奏する。また、上記実施例−ではメタケイ酸ナトリウム
水溶液を亜鉛アンミン錯体水溶液に滴下する場合につい
て説明したが、その逆の場合であってもよく上記実施例
と同様の効果を奏する。In addition, in the above example, the case where a zinc ammine complex was synthesized by adding aqueous ammonia was explained, but when the pH is from g to
Other zinc complexes that do not decompose or do not cause precipitation in the saw state and that contain a ligand that can be removed by heat treatment may be used, and the same effects as in the above embodiments can be achieved. In addition, although the above example describes the case where sodium metasilicate and zinc nitrate are used, other metasilicates, silicates,
A zinc compound may also be used, and the same effect as in the above embodiment can be achieved. Further, in the above example, a case was explained in which the sodium metasilicate aqueous solution was dropped into the zinc ammine complex aqueous solution, but the reverse case may be used and the same effects as in the above example can be obtained.

以上のように、この発明によれば亜鉛イオンを予め、ｐ
Ｈがｔ〜ｌコの状態において分解せず沈殿を生成しない
亜鉛錯体であり、熱処理により除去可能な配位子を含む
亜鉛錯体に変換して、ケイ酸イオン水溶液と反応させた
ので、高純度でかつ極めて粒度の細かいケイ酸亜鉛が再
現性良（得られる効果がある。As described above, according to the present invention, zinc ions are added to p
It is a zinc complex that does not decompose or form a precipitate when H is between t and l. It is converted into a zinc complex containing a ligand that can be removed by heat treatment and reacted with an aqueous silicate ion solution, resulting in high purity. Zinc silicate, which has a large and extremely fine particle size, has good reproducibility (effects obtained).

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はこの発明方法の一実施例に使用する合成装置を
示す概略構成図、第２図はこの発明方法の他実施例に使
用する合成装置を示す概略構成図である。 ！・・・ビーカー、コ・・・滴下ロート、３・・・リン
グ、弘゛°スタンド、Ｓ・・・ホットプレート付スター
ラー、６・・・攪拌子、７・・・亜鉛アンミン錯体水溶
液、ｊ・・・ケイ酸ナトリウム水溶液、？・・・水。 なお、図中同一符号は同一、または相当部分を示す。 代理人　大岩増雄FIG. 1 is a schematic diagram showing a synthesis apparatus used in one embodiment of the method of the present invention, and FIG. 2 is a schematic diagram showing a synthesis apparatus used in another embodiment of the method of the invention. ! ... Beaker, C... Dripping funnel, 3... Ring, wide stand, S... Stirrer with hot plate, 6... Stirrer, 7... Zinc ammine complex aqueous solution, J. ... Sodium silicate aqueous solution? ···water. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Masuo Oiwa

Claims (1)

【特許請求の範囲】[Claims] 亜鉛イオン水溶液とケイ酸イオン水溶液を混合してケイ
酸亜鉛を合成する際に、予め亜鉛イオンを、Ｃ，Ｈ，Ｎ
等より構成される配位子を含み、ｐＨが１−／コの状態
において分解せず沈殿を生じない亜鉛錯体に変換し、得
られた錯体なケイ酸イオン水溶液と反応させることを特
徴とするケイ酸亜鉛の製造方法。When synthesizing zinc silicate by mixing a zinc ion aqueous solution and a silicate ion aqueous solution, zinc ions are added in advance to C, H, N
It is characterized by converting it into a zinc complex that does not decompose or precipitate at a pH of 1-/co, and reacting it with the resulting complex aqueous silicate ion solution. Method for manufacturing zinc silicate.