JPH05140619A - Dissolving zinc grain and its production - Google Patents
Dissolving zinc grain and its productionInfo
- Publication number
- JPH05140619A JPH05140619A JP3326974A JP32697491A JPH05140619A JP H05140619 A JPH05140619 A JP H05140619A JP 3326974 A JP3326974 A JP 3326974A JP 32697491 A JP32697491 A JP 32697491A JP H05140619 A JPH05140619 A JP H05140619A
- Authority
- JP
- Japan
- Prior art keywords
- zinc
- particles
- zinc particles
- cooling medium
- dropping
- 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.)
- Withdrawn
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- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
- Powder Metallurgy (AREA)
- Electroplating And Plating Baths Therefor (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、亜鉛メッキ浴等の原料
として用いられる溶解性の良い亜鉛粒に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to highly soluble zinc particles used as a raw material for galvanizing baths and the like.
【従来技術とその課題】亜鉛メッキ浴等として用いられ
る硫酸亜鉛液を得るために、亜鉛粒を硫酸に溶解する場
合、従来の亜鉛粒は溶解性が低く、溶解性の良い亜鉛粒
が求められている。ところで溶解速度を高めるためには
粒径が微細な亜鉛粉末を用いることが考えられるが、亜
鉛粉末を硫酸に投入すると、亜鉛粉末と硫酸が急激に反
応し多量の水素ガスを発生して危険であり、また粉末を
取扱う煩雑さが伴う。そこでメッキ用亜鉛としては、従
来、粒径3〜6mm程度の亜鉛粒が一般に用いられている。
ところが従来用いられている亜鉛粒は、硫酸に対する溶
解速度が0.1g/hr程度であり、溶解速度が遅いため多量
の亜鉛を溶解するには溶解時間が長引く問題があった。
特に溶解初期の溶解速度が極めて遅く、メッキ浴の濃度
調整が難しい。具体的には、一例として溶解速度が1.0g
/hr以上であり、溶解３時間以内に溶解がほぼ終了する
ものが求められているが、現状では満足するものがな
い。Niイオンを亜鉛メッキ浴に添加することによって溶
解速度を高める方法も知られている(特公平3-6240号)
が、この方法においても溶解初期の溶解速度は必ずしも
大きくなく、しかもイオンとしてNi源を添加するために
硫酸ニッケル等を用いており、その添加量を亜鉛投入量
の増減に対応してその都度調整しなければならない煩わ
しさが伴う。2. Description of the Related Art When zinc particles are dissolved in sulfuric acid in order to obtain a zinc sulfate solution used as a galvanizing bath or the like, conventional zinc particles have low solubility, and zinc particles having good solubility are required. ing. By the way, in order to increase the dissolution rate, it is possible to use zinc powder with a fine particle size, but when zinc powder is added to sulfuric acid, the zinc powder and sulfuric acid react rapidly, generating a large amount of hydrogen gas, which is dangerous. Yes, and the complexity of handling the powder is involved. Therefore, as the zinc for plating, conventionally, zinc particles having a particle diameter of about 3 to 6 mm have been generally used.
However, the conventionally used zinc particles have a dissolution rate in sulfuric acid of about 0.1 g / hr, and there is a problem that the dissolution time is long to dissolve a large amount of zinc because the dissolution rate is slow.
In particular, the dissolution rate at the initial stage of dissolution is extremely slow, and it is difficult to adjust the concentration of the plating bath. Specifically, as an example, the dissolution rate is 1.0 g
It is required that the amount is not less than / hr and the dissolution is almost completed within 3 hours, but at present, there is no satisfactory one. A method of increasing the dissolution rate by adding Ni ions to the galvanizing bath is also known (Japanese Patent Publication No. 3-6240).
However, even in this method, the dissolution rate at the initial stage of dissolution is not always high, and nickel sulfate or the like is used to add the Ni source as ions, and the addition amount is adjusted each time in response to the increase or decrease of the zinc input amount. It involves the hassle of having to do it.
【０００２】[0002]
【発明の解決課題】本発明は従来の亜鉛粒にみられた上
記課題を解決するものであって、硫酸等への溶解性が格
段に優れた亜鉛粒を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention solves the above problems found in conventional zinc particles, and it is an object of the present invention to provide zinc particles having significantly excellent solubility in sulfuric acid and the like.
【０００３】[0003]
【課題の解決手段：発明の構成】本発明によれば、(イ)
表面積の10％以上が微細な結晶粒により形成された溶解
用亜鉛粒が提供される。また本発明によれば、(ロ) 溶融
亜鉛をノズルから冷却媒体に滴下して亜鉛粒を製造する
方法において、冷却媒体の温度を10〜90℃とし、かつ滴
下直前の亜鉛湯滴が冷却媒体に僅かに接する状態で溶融
亜鉛を滴下することにより、表面積の10％以上が微細な
結晶粒により形成された亜鉛粒を製造することを特徴と
する溶解用亜鉛粒の製造方法が提供される。According to the present invention, (a)
There is provided a zinc particle for melting, in which 10% or more of the surface area is formed by fine crystal particles. Further, according to the present invention, (b) in the method for producing zinc particles by dropping molten zinc from a nozzle into a cooling medium, the temperature of the cooling medium is 10 to 90 ° C., and the zinc hot water droplets immediately before the dropping is the cooling medium. There is provided a method for producing zinc particles for dissolution, characterized in that zinc particles having 10% or more of the surface area formed by fine crystal particles are produced by dropping molten zinc in a state of slightly contacting with.
【０００４】本発明において、亜鉛粒の表面が微細な亜
鉛結晶粒、特に0.1mm以上の微細な結晶粒によって形成
された多面状の亜鉛粒が硫酸等への溶解性に優れること
が認められた。粒子径6mm 、亜鉛の溶湯温度435 ℃、Ni
含有量10ppm の同一条件で、粒子表面に結晶粒が全く見
られないか又は極く僅かである亜鉛粒(No.1)、粒子表面
の10〜50％が0.1mm 以上の結晶粒によって形成された亜
鉛粒子(No.2)、粒子表面の70％程度が0.1mm 以上の結晶
粒によって形成された亜鉛粒子(No.3)を製造し、各々に
ついて硫酸(pH=1〜1.5、H2SO4:5.5〜6.5g/l)への溶解性
（溶解量、単位:g/l）を試験したところ図１の結果が得
られた。図１に示すように、粒子表面が0.1mm以上の微
細な結晶粒によって形成された亜鉛粒は、粒子表面に結
晶粒が殆どない従来の亜鉛粒に比べて２時間〜３時間後
の溶解量が約２〜３倍であり、溶解性が格段に優れてい
る。この理由は、結晶粒界での溶解が促進されるためで
あると思われる。なお、亜鉛粒表面の結晶粒が大き過ぎ
ると溶解性が低下するので好ましくない。通常0.1〜1.5
mm程度の粒径が好ましい。図１に示すように(試料No.2,
3)、亜鉛粒表面積の10％以上、好ましくは10〜50％が上
記結晶粒によって形成されていることが必要である。In the present invention, it was found that zinc crystal grains having fine zinc grains on the surface thereof, particularly polyhedral zinc grains formed by fine crystal grains of 0.1 mm or more, have excellent solubility in sulfuric acid and the like. .. Particle size 6 mm, molten metal temperature of zinc 435 ℃, Ni
Under the same conditions with a content of 10 ppm, there are no or very few crystal grains on the particle surface, zinc grains (No. 1), 10 to 50% of the grain surface is formed by crystal grains of 0.1 mm or more. Zinc particles (No.2), zinc particles (No.3) in which about 70% of the particle surface is formed by crystal grains with a diameter of 0.1 mm or more, and sulfuric acid (pH = 1 to 1.5, H 2 SO When the solubility (dissolution amount, unit: g / l) in 4 : 5.5 to 6.5 g / l) was tested, the results shown in FIG. 1 were obtained. As shown in Fig. 1, the zinc particles formed by fine crystal grains with a particle surface of 0.1 mm or more have a dissolution amount after 2 to 3 hours compared to conventional zinc particles with few crystal grains on the particle surface. Is about 2-3 times, and the solubility is remarkably excellent. The reason for this seems to be that the dissolution at the grain boundaries is promoted. If the crystal grains on the surface of the zinc grains are too large, the solubility will decrease, which is not preferable. Usually 0.1-1.5
A particle size on the order of mm is preferred. As shown in Figure 1, (Sample No. 2,
3) It is necessary that 10% or more, preferably 10 to 50%, of the surface area of zinc particles is formed by the above crystal particles.
【０００５】粒子表面が微細な結晶粒によって形成され
た亜鉛粒を製造するには、溶融亜鉛をノズルから冷却媒
体に滴下して亜鉛粒を製造する方法において、溶融亜鉛
の温度を425 〜470 ℃、冷却媒体の温度を10〜90℃と
し、かつ滴下直前の亜鉛湯滴が冷却媒体に僅かに接する
状態で溶融亜鉛を滴下することにより、表面積の10％以
上が微細な結晶粒により形成された亜鉛粒を製造するこ
とができる。冷却媒体として通常は冷却水が用いること
ができる。冷却水温が５℃以下の場合には、亜鉛粒表面
に全く結晶粒が見られず、しかも非常に緻密な組織とな
り硫酸への溶解が困難になる。冷却水温が高くなるにつ
れて亜鉛粒表面に微細な結晶粒が多くなると共に0.1mμ
以下の微細な孔が多くなり組織が多孔質になる。水温10
℃〜60℃では粒子表面積の10〜50％が結晶粒となり、水
温が90℃程度では粒子表面積の70％が結晶粒となる。水
温が90℃を越えると冷却が遅く結晶粒が成長せず、また
水中の溶存酸素によって表面が酸化され酸化被膜が形成
されるので硫酸への初期の溶解性が低下する。なお粒子
表面の結晶粒は電子顕微鏡によって確認することができ
る。亜鉛の湯温は425℃〜470℃以下が好ましい。425℃
より低いと融点に近く粘性が高過ぎて滴下が困難にな
る。また470℃より高いと溶湯を滴下する際の制御が難
しくなり、また冷却時の温度差が大きくり非晶質化し易
くなるので好ましくない。In order to produce zinc particles whose surface is formed of fine crystal grains, the temperature of molten zinc is 425 to 470 ° C. in the method of producing zinc particles by dropping molten zinc into a cooling medium from a nozzle. , 10% or more of the surface area was formed by fine crystal grains by setting the temperature of the cooling medium to 10 to 90 ° C. and adding molten zinc in a state where the zinc hot water droplet just before the dropping was in slight contact with the cooling medium. Zinc particles can be produced. Cooling water can usually be used as the cooling medium. When the cooling water temperature is 5 ° C. or lower, no crystal grains are observed on the surface of zinc grains, and a very dense structure is formed, making it difficult to dissolve in sulfuric acid. As the cooling water temperature increases, the number of fine crystal grains on the surface of zinc grains increases and 0.1 mμ
The following fine pores increase and the structure becomes porous. Water temperature 10
At 50 to 60 ° C, 10 to 50% of the particle surface area becomes crystal grains, and at a water temperature of about 90 ° C, 70% of the particle surface area becomes crystal grains. When the water temperature exceeds 90 ° C, cooling is slow and crystal grains do not grow, and the surface is oxidized by dissolved oxygen in water to form an oxide film, so that the initial solubility in sulfuric acid decreases. The crystal grains on the particle surface can be confirmed by an electron microscope. The temperature of the hot water of zinc is preferably 425 ° C to 470 ° C or lower. 425 ° C
When it is lower, the melting point is close to the melting point and the viscosity is too high to make the dropping difficult. On the other hand, if the temperature is higher than 470 ° C., it becomes difficult to control the dropping of the molten metal, and the temperature difference during cooling becomes large, so that it becomes easy to become amorphous, which is not preferable.
【０００６】亜鉛粒の結晶構造および粒径が同一である
とき、表面酸化被膜のない亜鉛粒が硫酸への溶解性に優
れる。同一の溶融亜鉛から製造した粒径6mmの亜鉛粒に
ついて、0.3μmの酸化被膜を有するもの(No.11)、酸洗
浄して酸化被膜を除去したもの(No.12)、3.5μmの酸化
被膜を有するもの(No.13,14)の各々について硫酸への溶
解性（溶解量、単位:g/l）を試験したところ図２の結果
が得られた。図２に示すように、酸化被膜のない亜鉛粒
は溶解初期において格段に高い溶解性を示す。なお、酸
化被膜がなく、又は薄いものは溶解した際に酸化物とし
て失われる損失分が小さい利点もある。因みに従来の亜
鉛粒は膜厚2.5μm程度の酸化被膜が不可避的に生じてお
り、５％程度の亜鉛分が酸化物として損失している。When the crystal structure and particle size of zinc particles are the same, zinc particles without a surface oxide film have excellent solubility in sulfuric acid. Regarding zinc particles with a particle diameter of 6 mm manufactured from the same molten zinc, those with an oxide film of 0.3 μm (No. 11), those with an oxide film removed by acid cleaning (No. 12), oxide film of 3.5 μm The results of FIG. 2 were obtained when the solubility in sulfuric acid (dissolution amount, unit: g / l) was tested for each of the compounds having No. As shown in FIG. 2, zinc particles having no oxide film show remarkably high solubility in the initial stage of dissolution. In addition, there is an advantage that a loss that is lost as an oxide when it is dissolved is small if it has no oxide film or is thin. Incidentally, the conventional zinc particles inevitably have an oxide film with a film thickness of about 2.5 μm, and about 5% of zinc content is lost as an oxide.
【０００７】酸化被膜が0.3μm以下の亜鉛粒を製造する
には、滴下ノルズから冷却水面に至る滴下雰囲気の酸素
濃度を1％以下にすると良い。溶融亜鉛の温度470℃、ノ
ズル口径1.5mm、ノズル開口から冷却水面までの落下距
離10mm、の条件下で、燃焼バーナの燃焼排ガスでノズル
開口を覆い、酸素濃度を 5％〜0.05％まで変え、ノズル
から溶融亜鉛を冷却水に滴下して亜鉛粒子を製造した。
この結果を表１に示す。In order to produce zinc particles having an oxide film of 0.3 μm or less, the oxygen concentration in the dropping atmosphere from the dropping nord to the cooling water surface should be 1% or less. Under the conditions of molten zinc temperature of 470 ℃, nozzle diameter of 1.5 mm, and dropping distance of 10 mm from the nozzle opening to the cooling water surface, cover the nozzle opening with the combustion exhaust gas of the combustion burner and change the oxygen concentration from 5% to 0.05%. Molten zinc was dropped from a nozzle into cooling water to produce zinc particles.
The results are shown in Table 1.
【０００８】[0008]
【表１】 ───────────────────────────── 酸素濃度（％） 5.0 1.0 0.5 0.3 0.15 0.05 表面被膜の膜厚(μm) 1.8 0.85 0.75 0.30 0.10 0.03 ─────────────────────────────[Table 1] ───────────────────────────── oxygen concentration (%) 5.0 1.0 0.5 0.3 0.15 0.05 Thickness of surface coating ( μm) 1.8 0.85 0.75 0.30 0.10 0.03 ─────────────────────────────
【０００９】なお、酸化被膜の厚さは、EPMAにより測定
すると同時に、酸化被膜を有する亜鉛粒子100gを正確に
秤量後、塩化アンモン水溶液に浸漬して表面の被膜を溶
解除去した後に水洗乾燥して秤量し、重量減少から酸化
被膜量を算出し、これを粒子表面積との関係から算出で
きる。The thickness of the oxide film was measured by EPMA. At the same time, 100 g of zinc particles having an oxide film were accurately weighed, immersed in an aqueous solution of ammonium chloride to dissolve and remove the film on the surface, and then washed with water and dried. It is possible to weigh and calculate the oxide film amount from the weight reduction, and to calculate this from the relationship with the particle surface area.
【００１０】滴下ノズルから冷却水面までの滴下距離
は、ノズル口から滴下直前の亜鉛湯滴が冷却水面に僅か
に接する程度が好ましい。この滴下距離の場合、一例と
して溶湯温度450〜460℃、冷却水温65〜70 ℃の条件
で、表面積の15〜50％の範囲が0.1〜2.0mmの結晶粒によ
って形成された亜鉛粒が得られる。なお、ある程度形状
が変形しても良い場合には、粒径の約10〜20倍の滴下距
離とすることにより、亜鉛融体(湯滴)を冷却水面に衝突
させて微細な結晶粒を形成させることもできる。The dropping distance from the dropping nozzle to the cooling water surface is preferably such that the zinc hot water droplets just before dropping from the nozzle opening slightly contact the cooling water surface. In the case of this dropping distance, for example, under the conditions of a molten metal temperature of 450 to 460 ° C and a cooling water temperature of 65 to 70 ° C, zinc particles formed by crystal grains of 0.1 to 2.0 mm in the range of 15 to 50% of the surface area are obtained. .. If the shape may be deformed to some extent, a zinc melt (water droplets) collides with the cooling water surface to form fine crystal grains by making the dropping distance approximately 10 to 20 times the grain size. You can also let it.
【００１１】実施例 表２に示す製造条件に従い、Ni含有量10ppmの溶融亜鉛
から、粒子表面に結晶面が全く見られないか又は極く僅
かである亜鉛粒(No.1)、粒子表面の10〜50％が0.1mm 以
上の結晶粒によって形成された亜鉛粒子(No.2)、粒子表
面の70％程度が0.1mm 以上の結晶粒によって形成された
亜鉛粒子(No.3)を製造し、各々について硫酸への溶解性
(溶解量、単位:g/l)を試験し、図１の結果を得た。図１
に示すように本発明の亜鉛粒(実施例No.2,3)は粒子表面
に結晶粒がみられない従来の亜鉛粒(No.1:比較例)に比
較して硫酸への溶解性が格段に大きい。Example According to the production conditions shown in Table 2, from the molten zinc having a Ni content of 10 ppm, no crystal plane was observed on the particle surface or there were very few zinc particles (No. 1), We manufacture zinc particles (No. 2) with 10 to 50% formed by crystal grains of 0.1 mm or more, and zinc particles (No. 3) formed by about 70% of the particle surface with crystal grains of 0.1 mm or more. , Solubility in sulfuric acid for each
(Dissolved amount, unit: g / l) was tested and the results shown in FIG. 1 were obtained. Figure 1
As shown in Fig. 3, the zinc particles of the present invention (Examples Nos. 2 and 3) have a higher solubility in sulfuric acid than the conventional zinc particles (No. 1: Comparative Example) in which crystal grains are not found on the particle surface. Remarkably large.
【００１２】[0012]
【表２】 ────────────────────────────── 試料 粒径 溶湯温度 冷却水温 滴下距離 表面の組織状態 No.1 6mm 435℃ 22〜23℃ 6〜7mm 非結晶面 No.2 6mm 435℃ 70〜71℃ 4〜5mm 結晶粒が10〜50% No.3 6mm 435℃ 70〜71℃ 2〜3mm 結晶粒が70%以上 ──────────────────────────────[Table 2] ────────────────────────────── Sample grain size Molten metal temperature Cooling water temperature Dropping distance Surface texture No.1 6mm 435 ℃ 22〜23 ℃ 6〜7mm Amorphous surface No.2 6mm 435 ℃ 70〜71 ℃ 4〜5mm 10〜50% No.3 6mm 435 ℃ 70〜71 ℃ 2〜3mm Grain 70 % Or more ──────────────────────────────
【００１３】[0013]
【発明の効果】本発明の亜鉛粒は、従来の亜鉛粒に比較
して格段に溶解性に優れ、亜鉛メッキ浴などを従来より
短時間で得ることができる。EFFECTS OF THE INVENTION The zinc particles of the present invention have much higher solubility than conventional zinc particles, and a zinc plating bath or the like can be obtained in a shorter time than before.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明に係る多面体亜鉛粒子と従来の非多面体
亜鉛粒子の溶解性を示すグラフ。FIG. 1 is a graph showing the solubility of polyhedral zinc particles according to the present invention and conventional non-polyhedral zinc particles.
【図２】本発明に係る酸化被膜を有しない亜鉛粒子と従
来の酸化被膜を有する亜鉛粒子の溶解性を示すグラフ。FIG. 2 is a graph showing the solubility of zinc particles having no oxide film according to the present invention and conventional zinc particles having an oxide film.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 // Ｃ２５Ｄ 3/22 １０１ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Office reference number FI technical display location // C25D 3/22 101
Claims (4)
形成された溶解用亜鉛粒。1. Dissolving zinc particles having a surface area of 10% or more formed of fine crystal particles.
項１の溶解用亜鉛粒。2. The zinc particles for melting according to claim 1, wherein the oxide film on the surface is 1 μm or less.
て亜鉛粒を製造する方法において、冷却媒体の温度を10
〜90℃とし、かつ滴下直前の亜鉛湯滴が冷却媒体に僅か
に接する状態で溶融亜鉛を滴下することにより、表面積
の10％以上が微細な結晶粒により形成された亜鉛粒を製
造することを特徴とする溶解用亜鉛粒の製造方法。3. A method for producing zinc particles by dropping molten zinc into a cooling medium from a nozzle, wherein the temperature of the cooling medium is 10
By adding molten zinc at a temperature of ~ 90 ° C and in a state where the zinc hot water droplets are in slight contact with the cooling medium immediately before dropping, it is possible to produce zinc particles in which 10% or more of the surface area is formed by fine crystal grains. A method for producing zinc particles for melting characterized.
酸素濃度が１％以下である請求項２の製造方法。4. The manufacturing method according to claim 2, wherein the oxygen concentration in the dropping atmosphere from the nozzle to the cooling medium is 1% or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3326974A JPH05140619A (en) | 1991-11-15 | 1991-11-15 | Dissolving zinc grain and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3326974A JPH05140619A (en) | 1991-11-15 | 1991-11-15 | Dissolving zinc grain and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05140619A true JPH05140619A (en) | 1993-06-08 |
Family
ID=18193886
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3326974A Withdrawn JPH05140619A (en) | 1991-11-15 | 1991-11-15 | Dissolving zinc grain and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05140619A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107884259A (en) * | 2017-11-06 | 2018-04-06 | 南京大学 | The device and method of minor material high speed cooling is realized using drop cooling |
-
1991
- 1991-11-15 JP JP3326974A patent/JPH05140619A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107884259A (en) * | 2017-11-06 | 2018-04-06 | 南京大学 | The device and method of minor material high speed cooling is realized using drop cooling |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990204 |