JPH0229760B2 - - Google Patents
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- Publication number
- JPH0229760B2 JPH0229760B2 JP61013230A JP1323086A JPH0229760B2 JP H0229760 B2 JPH0229760 B2 JP H0229760B2 JP 61013230 A JP61013230 A JP 61013230A JP 1323086 A JP1323086 A JP 1323086A JP H0229760 B2 JPH0229760 B2 JP H0229760B2
- Authority
- JP
- Japan
- Prior art keywords
- zinc
- plating
- metal
- plate
- solution
- 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
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- 239000011701 zinc Substances 0.000 claims description 94
- 238000007747 plating Methods 0.000 claims description 81
- 239000007788 liquid Substances 0.000 claims description 50
- PTFCDOFLOPIGGS-UHFFFAOYSA-N Zinc dication Chemical compound [Zn+2] PTFCDOFLOPIGGS-UHFFFAOYSA-N 0.000 claims description 28
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 25
- 238000000034 method Methods 0.000 claims description 25
- 229910052725 zinc Inorganic materials 0.000 claims description 25
- 238000009713 electroplating Methods 0.000 claims description 14
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 229910052751 metal Inorganic materials 0.000 description 32
- 239000002184 metal Substances 0.000 description 32
- 238000004090 dissolution Methods 0.000 description 26
- 239000000243 solution Substances 0.000 description 24
- 229910021645 metal ion Inorganic materials 0.000 description 19
- 230000007423 decrease Effects 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 230000001737 promoting effect Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005323 electroforming Methods 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002923 metal particle Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- RZLVQBNCHSJZPX-UHFFFAOYSA-L zinc sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Zn+2].[O-]S([O-])(=O)=O RZLVQBNCHSJZPX-UHFFFAOYSA-L 0.000 description 1
Description
＜産業上の利用分野＞
本発明は、電気めつきにおける金属イオン供給
方法およびその装置に関し、特に不溶性陽極を使
用する亜鉛系電気めつきにおける亜鉛イオン供給
方法およびその装置に関する。
＜従来技術およびその問題点＞
近年、鋼材、鋼板等の電気めつきにおいては、
めつき液中のめつき金属イオン溶解量の安定化や
消費電力低減化等のため、めつき液中にめつき金
属イオンを溶出しない不溶性陽極を使用する電気
めつきが指向されている。金属めつきとしては
種々のものが使われているが、代表例としてZn
について述べる。
不溶性陽極によるZnめつきでは、一般に硫酸
塩浴が用いられ、その陰、陽極の反応はそれぞれ
陰極 Zn2＋2e→Zn ……(1)
陽極 SO4 2-＋H2O
→H2SO4＋1/2O2↑＋2e ……(2)
である。すなわち、めつき液中において、(1)によ
るZn2+の減少と、(2)によるPHの低下が起こるた
めに、金属イオンの供給を連続的に、または定期
的に行う必要がある。
Znめつきの場合、金属イオンの供給源として
Zn金属またはその酸化物、水酸化物、炭酸塩な
どがあり、その供給方法としてコスト面、作業性
などから、Zn金属をZn2+の減少しためつき液に
浸漬し、溶解する方法が採られている。この時の
反応は
Zn＋H2SO4→ZnSO4＋H2↑ ……(3)
であり、金属イオン（Zn2+）の増加とPHの上昇
が起こる。すなわち、この(3)の反応により、前述
した電気めつき時での(1)、(2)の反応によるZn2+
の減少とPHの低下を同時に補うことができ、好都
合である。
めつき液に金属イオンを供給する方法として従
来、流動層方式やバレル方式などがある。
流動層方式は、例えば特開昭58−151489号公報
等に開示されており、第５図に示すように、めつ
き金属粉を装入した竪立の流動筒３０に、導入管
３１を介して、金属イオンが減少し且つPHの低下
しためつき浴槽のめつき液を、該金属粉がキヤリ
ーオーバーせずに流動層３２を形成するように連
続的に供給し、金属イオンが増加し且つPHの上昇
しためつき液を導出管３３を介してめつき浴槽に
導出し、金属イオンの供給を行うものである。
しかしこの方式では、流動筒３０内のめつき液
が一定PH以上（例えばPH５以上）に上昇すると、
金属粉の表面に水酸化物の皮膜が形成され、金属
イオンの生成が停止するため、金属イオンの供給
が妨げられるという欠点を有している。さらに、
該めつき液をめつき液槽へ導出する際、同時に微
細な金属粉が導出されたり、ひいてはめつき浴槽
内に流入し、ロールに付着した場合、めつき製品
に押しキズなどが発生し、めつき製品特性値を著
しく害する恐れがある。
一方、特開昭60−25761号公報等に開示されて
いるバレル方式がある。これは、第６図に示すよ
うに、液槽４０内には、めつき液４１に浸漬し
て、外周に多数の孔４２を有し、内部に金属粒４
３を有する中空回転体バルレ４４が回転自在に設
けられている。ホツパー４５および導入管４６か
ら金属イオン濃度の減少しためつき浴槽のめつき
液が、それぞれ中空回転体４４に供給され、中空
回転体４４が回転して金属粒４３同士の接触を行
わせ、各金属粒４３表面に生成する水酸化物の皮
膜を破壊して金属粒４３の溶解を促進し、この溶
解により、金属イオン濃度の増大しためつき液
を、導出管４８を介して液槽４０から導出する方
式である。しかし、金属イオンの供給律するもの
は、前述のようにめつき液中のPHであるので、本
方式においてもPHが４近くになると溶解速度が極
端に低下するという問題がある。
＜発明の目的＞
本発明の目的は、上記従来技術の問題点を解消
しようとするものであつて、
(1) めつきにより消費される金属イオンの供給に
見合う金属の溶解速度を得ること
(2) 上記(1)により、同時にめつきによるPHの低下
を補うことができること
に着目し、めつきにより消費される金属量を算出
し、本発明法である液流動方式により電鋳Zn板
を効率的に化学溶解させることにより、金属イオ
ンの収支を図ることができる亜鉛系電気めつきに
おける亜鉛イオン供給方法およびその装置を提供
するもである。
＜発明の構成＞
本発明者らは、めつき金属の溶解促進につい
て、特にZnを代表例として、
(1) Zn金属の形状影響
(2) 液流速の影響
(3) 液PHの影響
の検討を行つた。
その結果、
(1)ではZn溶解速度：電鋳Zn板＞Zn玉（４〜８
mmφ）＞Znチツプ（15〜20mmφ×L20mm）＞Zn板
（５mm厚）
(2)ではZn溶解速度：液流速0.5〜2.0m／sec＞
0.5m／sec未満
(3)ではZn溶解速度：PH０〜２未満＞PH２以上
であることに着目し、これをめつき金属イオンの
溶解促進に応用することによつて、本発明を完成
することができた。
本発明によれば、亜鉛系電気めつきを行なうめ
つき浴槽からの亜鉛イオン濃度が低下した循環め
つき液を電鋳亜鉛板をめつき液の流れ方向に平行
に配置させた溶解装置内を0.5〜2m／秒の流速で
通過させて得た亜鉛イオン濃度の上昇した液を、
前記または他のめつき浴槽に供給することを特徴
とする亜鉛系電気めつきにおける亜鉛イオン供給
方法が提供される。
また本発明によれば、亜鉛系電気めつきを行な
うめつき浴槽と、該めつき浴槽からの亜鉛イオン
濃度が低下した循環めつき液を配管系を経て通過
させて該循環めつき液の亜鉛イオン濃度を上昇さ
せるために電鋳亜鉛板をめつき液の流れ方向に平
行に配置した液流動溶解装置と、この溶解液を前
記または他のめつき浴槽に導く配管系とを備える
ことを特徴とする亜鉛系電気めつきにおける亜鉛
イオン供給装置が提供される。
以下に本発明を更に詳細に説明する。
本発明は、めつき浴槽からの亜鉛イオン濃度の
低下しためつき液を、金属亜鉛を充填させた溶解
装置内を通過させて前記亜鉛イオン濃度を上昇さ
せてめつき浴槽に送り込む方法および装置につい
てであるが、めつき浴槽に亜鉛イオン濃度が上昇
しためつき液のみを効率よく送り込み、めつき金
属の未溶解物が一緒に送り込まれることを防止し
てめつき製品に解しキズ等がつくことを防ぐこと
を目的とする。
ここで電鋳Zn板とは、亜鉛鉱石を酸溶解した
電解液を用いて、アルミ板を陰極にして低電流密
度でZnを電析させて、３〜５mm厚の板状とした
のち、アルミ板から機械的に剥離したものであ
る。アルミ板と接触しない反対面の表面は、通常
のZn板の表面が平滑であるのに対し、著しく凹
凸大で（0.5〜３mm程度）、しかも、厚さ方向にピ
ンホールを有するものである（表面積大は溶解速
度大となり、好都合）。
なお、Zn地金の原料であるためきわめて安価
である。電鋳亜鉛板は第２図に図示するように、
めつき液の流れ方向に平行に配置する。このよう
に配置することにより、以下に述べるめつき流と
電鋳板との接触する相対速度のコントロールが容
易に行える。
液流速は0.5〜2.5m／secにするのが好ましい。
その理由は、上記範囲内の液流速ではZn金属の
溶解でZn金属表面よりH2ガスが発生するが、液
流速が0.5m／sec未満だとH2ガスがZn金属表面
に吸着して溶解速度が著しく低下し、液流速
2.5m／sec超では溶解速度の効果が液流速0.5〜
2.5m／secの場合とほぼ等しいことから、必要以
上の電力費を費やすことになるからである。
また、溶解するZn金属の基体は電鋳Zn板が好
ましい。その理由は、前述のように表面積が大
（凹凸が著しく、多数のピンホールを含む）であ
ることから通常のZn金属板よりもエツチング力
が大であり、上記高速液流に電鋳板Zn板への衝
突による該電鋳Zn板表面に吸着のH2ガス排除、
および空気（O2）供給によるカソード反応
H2O＋1/2O2＋2e→2OH- ……(4)
の促進により、通常のZn金属板（厚さ５mmのZn
板）よりも著しくZn金属を溶解促進することが
できるからである。
さらに、めつき液PHを0.5〜2.0にするが好まし
く、それは、以下の理由による。
例えば、亜鉛めつきの不溶性陽極によるめつき
における代表的な浴組成は
ZnSO4・7H2O 300〜500ｇ／
Na2SO4 30ｇ／
Al2（SO4）3・17H2O 50ｇ／
PH １〜３
である。近年めつき液PH３→１→0.5が指向され
ている。Zn金属の溶解促進において、亜鉛イオ
ンの供給速度を律するものは、めつき液中のH+
であり、H+濃度が低いほど金属イオンの供給速
度が高められるが、PH＜0.5では、電解と同時に
不溶性陽極（例えばPb―Sn5％アノード）の溶解
によつて、Pbイオンがめつき液中に溶出されや
すくなり、ひいてはめつき製品特性値を悪化させ
る欠点があるためであり、PH＞２では鋼板より溶
解したFeが、Fe（OH）3の沈澱を生成しやすくな
るとともに、本発明法に用いる電鋳Zn板であつ
ても、Zn金属の溶解速度が低下し、めつきによ
り消費されるZn量に見合うだけの溶解速度を得
ようとすると、１セル（１めつき浴槽）当りの液
流動溶解装置の必要台数が大幅にアツプし、建設
コストが高くつき現実性に欠けるためである。
次に、本発明の亜鉛イオン供給装置の好適実施
例について更に詳細に説明する。
第１図は本発明の亜鉛イオン供給方法に使用さ
れる亜鉛イオン供給装置を示し、本供給装置はめ
つき浴槽１、液流動溶解装置２およびサーキユレ
ーシヨンタンク４を有する。
第２図に示すように、液流動溶解装置２内には
複数の電鋳Zn板７が互いに所定間隔をなして層
状に配置され、その長手方向両側面が金属やプラ
スチツク等から成るネツト９によつて囲繞されて
いる。この電鋳Zn板７の方向は、該液流動溶解
装置２の一側壁上部に連通開口するノズル５ａか
ら対向側壁下部に連通開口するノズル１５ａに流
れる液流の方向と同方向に設定され、液流が電鋳
Zn板７間をスムーズに流れるようになつている。
これらノズル５ａ，１５ａはそれぞれパイプ５，
１５の一端をなしている。
サーキユレーシヨンタンク４は、亜鉛イオン濃
度の低下しためつき液が通過する液槽４ａと、亜
鉛イオン濃度の上昇しためつき液が通過する液槽
４ｂを有し、液槽４ａはパイプ８，５を介してそ
れぞれめつき浴槽１と液流動溶解装置２に、液槽
４ｂはパイプ２１，１５を介してそれぞれめつき
浴槽１と液流動溶解装置２に連通している。
そしてめつき浴槽１にて亜鉛イオン濃度の低下
しためつき液がパイプ８→液槽４ａからポンプ６
を介してパイプ５→ノズル５ａ→液流動溶解装置
２へ送り込まれる。該装置２内においてZn溶解
によつて前記めつき液は亜鉛イオン濃度が上昇す
る。
この亜鉛イオン濃度の上昇しためつき液はノズ
ル１５ａ→パイプ１５→液槽４ｂ→パイプ２１を
経て再びめつき浴槽１あるいは他のめつき浴槽に
供給される。
なお、ノズル５ａ，１５ａは、液流速を0.5〜
2.0m／secに保つため、10〜30mm×1000mm程度に
設定されている。
＜実施例＞
上記構成のイオンの供給装置を用いて、電鋳
Zn板（東邦亜鉛製1706）を50Kg充填し、これに
0.5〜2.5m／secの液流でめつき液を連続的に供給
し、Zn金属を溶解促進させて溶解率を求めた。
使用しためつき浴は、組成
ZnSO4・7H2O 460ｇ／
Na2SO4 50ｇ／
Al2（SO4）3・17H2O 30ｇ／
PH 0.5〜2.0
浴 温 55〜60℃
のものを用いた。
上記条件下でZn金属の溶解量を測定した結果
を表１および第３図、第４図に示す。
Zn金属の溶解促進にはZn金属の形状、液流速
およびめつき液PHが影響し、本発明法の溶解する
Zn金属として電鋳Zn板がZn板より優れているこ
とがわかる。前記めつき浴組成から電気Znめつ
きへ適用の条件を求め本発明法の妥当性を下記計
算により示す。
電気めつきで消費されるZn量は、たとえば電
源容量40000A／cellで1hrめつき当り
40000A／cell／96500C×32.7×602×１／103≒50Kg／
hrで
ある。
従つて電鋳Zn板の溶解効率は、
〔1〕 （PH0.5、液流速0.6〜1.5m／secレベル）で
は、0.6（60％）／3hr＝0.2／hr
〔2〕 （PH１、液流速0.6〜1.5m／secレベル）で
は0.2（20％）／3hr＝0.067／hr
である。
10hrめつき当りでは
〔１〕で、10×50／0.2＝2500KgのZn金属を有する
溶解装置が必要
〔２〕では、10×50／0.067＝7463KgのZn金属を有す
る溶解装置が必要
である。
今、液流動装置の電鋳Zn板の占有効率を35％
とすると、1cell当りに必要な液流動装置の台数
は、
〔１〕で2.5×103／4.5（電鋳Zn板の比重）×１／0.3
5＝1.59m3
〔２〕で7.5×103／4.5（比重）×１／0.35＝4.76m3
となる。
液流動装置の大きさを長さＬ＝１ｍ、奥行
（幅）Ｗ＝１ｍ、高さＨ＝２ｍとすると、
Ｖ＝L.W.H＝２m3
従つて、〔１〕では1.59／２＝0.8（１台で可）〔２
〕
では、4.76／２＝2.4（約２台で可）
となる。
しかし、Zn板を使用した場合は、溶解速度が
電鋳Zn板の1/3〜1/5であるから、上記の約４倍
必要で、実用的でないことがわかる。
<Industrial Application Field> The present invention relates to a method and apparatus for supplying metal ions in electroplating, and particularly to a method and apparatus for supplying zinc ions in zinc-based electroplating using an insoluble anode. <Prior art and its problems> In recent years, in electroplating of steel materials, steel plates, etc.
In order to stabilize the amount of plating metal ions dissolved in the plating solution and to reduce power consumption, electroplating using an insoluble anode that does not elute plating metal ions into the plating solution is being developed. Various types of metal plating are used, but a typical example is Zn.
Let's talk about. In Zn plating with an insoluble anode, a sulfate bath is generally used, and the reactions at the anode and cathode are as follows: Cathode Zn 2 +2e→Zn ……(1) Anode SO 4 2- +H 2 O →H 2 SO 4 +1/ 2O 2 ↑＋2e ……(2). That is, in the plating solution, since a decrease in Zn 2+ due to (1) and a decrease in PH due to (2) occur, it is necessary to supply metal ions continuously or periodically. In the case of Zn plating, as a source of metal ions
Zn metal or its oxides, hydroxides, carbonates, etc. are available, and the method of supplying them is to immerse the Zn metal in a plating solution with reduced Zn 2+ and dissolve it due to cost and workability reasons. It is being The reaction at this time is Zn + H 2 SO 4 →ZnSO 4 +H 2 ↑ ...(3), and an increase in metal ions (Zn 2+ ) and a rise in PH occur. That is, due to reaction (3), Zn 2+ due to reactions (1) and (2) during electroplating described above
It is convenient because it can compensate for the decrease in pH and the decrease in pH at the same time. Conventional methods for supplying metal ions to a plating solution include a fluidized bed method and a barrel method. The fluidized bed method is disclosed, for example, in Japanese Patent Application Laid-Open No. 151489/1989, and as shown in FIG. Then, the plating solution in the plating bath in which the metal ions are reduced and the pH is lowered is continuously supplied so that the metal powder does not carry over and forms a fluidized bed 32, and the metal ions are increased. In addition, the plating liquid with increased pH is led out to the plating bath via the lead-out pipe 33, and metal ions are supplied. However, in this method, when the plating liquid in the flow tube 30 rises to a certain pH or higher (for example, pH5 or higher),
This method has the disadvantage that a hydroxide film is formed on the surface of the metal powder and the production of metal ions is stopped, which impedes the supply of metal ions. moreover,
When the plating liquid is discharged into the plating liquid tank, if fine metal powder is discharged at the same time or flows into the plating bath and adheres to the roll, press scratches may occur on the plated product. There is a risk that the properties of the plated product will be significantly impaired. On the other hand, there is a barrel method disclosed in Japanese Patent Application Laid-Open No. 60-25761. As shown in FIG. 6, a liquid tank 40 is immersed in a plating liquid 41, has a large number of holes 42 on its outer periphery, and has metal grains 4 inside.
A hollow rotating body valve 44 having a diameter of 3 is rotatably provided. The plating solution in the plating bath with reduced metal ion concentration is supplied from the hopper 45 and the inlet pipe 46 to the hollow rotating body 44, which rotates to bring the metal particles 43 into contact with each other. The hydroxide film formed on the surface of the metal grains 43 is destroyed to promote dissolution of the metal grains 43, and as a result of this dissolution, the tamping solution with increased metal ion concentration is discharged from the liquid tank 40 through the outlet pipe 48. This is a method to derive. However, as described above, what controls the supply of metal ions is the pH in the plating solution, so even in this method there is a problem that the dissolution rate is extremely reduced when the pH approaches 4. <Objective of the Invention> The object of the present invention is to solve the above-mentioned problems of the prior art, and is to (1) obtain a metal dissolution rate commensurate with the supply of metal ions consumed by plating ( 2) Focusing on the fact that (1) above can compensate for the decrease in PH due to plating, the amount of metal consumed by plating was calculated, and electroformed Zn sheets were made using the liquid flow method of the present invention. The present invention provides a method and apparatus for supplying zinc ions in zinc-based electroplating, which can balance the balance of metal ions through efficient chemical dissolution. <Structure of the Invention> The present inventors investigated the promotion of dissolution of plated metals, particularly with Zn as a representative example, by investigating (1) influence of shape of Zn metal, (2) influence of liquid flow rate, and (3) influence of liquid PH. I went to As a result, in (1), Zn dissolution rate: electroformed Zn plate > Zn ball (4 to 8
mmφ)＞Zn chip (15~20mmφ×L20mm)＞Zn plate (5mm thickness) (2) Zn dissolution rate: liquid flow rate 0.5~2.0m/sec＞
For less than 0.5 m/sec (3), the present invention was completed by focusing on the fact that Zn dissolution rate: PH 0 to less than 2 > PH 2 or more, and applying this to promoting dissolution of plating metal ions. was completed. According to the present invention, a circulating plating solution with a reduced zinc ion concentration from a plating bath in which zinc-based electroplating is performed is passed through a melting device in which an electroformed zinc plate is arranged parallel to the flow direction of the plating solution. The liquid with increased zinc ion concentration obtained by passing it at a flow rate of 0.5 to 2 m/s is
There is provided a method for supplying zinc ions in zinc-based electroplating, which is characterized in that the zinc ions are supplied to the above or other plating baths. Further, according to the present invention, a plating bath in which zinc-based electroplating is performed and a circulating plating solution with a reduced concentration of zinc ions from the plating bath are passed through a piping system to remove zinc in the circulating plating solution. It is characterized by comprising a liquid flow dissolving device in which electroformed zinc plates are arranged parallel to the flow direction of the plating solution in order to increase the ion concentration, and a piping system that guides the dissolving solution to the above or other plating bath. A zinc ion supply device for zinc-based electroplating is provided. The present invention will be explained in more detail below. The present invention relates to a method and an apparatus for passing a plating liquid with a reduced zinc ion concentration from a plating bath through a dissolving device filled with metallic zinc to increase the zinc ion concentration and sending it into a plating bath. However, since the concentration of zinc ions increases in the plating bath, only the tamping solution is efficiently sent to the plating bath, preventing the undissolved matter of the plating metal from being sent together, which can cause cracks and other damage to the plating products. The purpose is to prevent this. Here, the electroformed Zn plate is made by electrodepositing Zn at a low current density using an electrolytic solution containing zinc ore dissolved in acid, using an aluminum plate as a cathode to form a plate with a thickness of 3 to 5 mm. It is mechanically peeled off from the board. While the surface of a normal Zn plate is smooth, the surface on the other side that does not come into contact with the aluminum plate is significantly uneven (approximately 0.5 to 3 mm) and has pinholes in the thickness direction ( A large surface area increases the dissolution rate, which is advantageous). Furthermore, since it is a raw material for Zn metal, it is extremely inexpensive. As shown in Figure 2, the electroformed zinc plate is
Arrange parallel to the flow direction of the plating solution. With this arrangement, the relative speed at which the plating flow and the electroformed plate come into contact with each other can be easily controlled as described below. The liquid flow rate is preferably 0.5 to 2.5 m/sec.
The reason for this is that when the liquid flow rate is within the above range, H 2 gas is generated from the Zn metal surface due to dissolution of the Zn metal, but when the liquid flow rate is less than 0.5 m/sec, H 2 gas is adsorbed to the Zn metal surface and dissolved. The speed is significantly reduced and the liquid flow rate
At over 2.5 m/sec, the effect of dissolution rate is 0.5 to 0.5 m/sec.
This is because it is almost the same as the case of 2.5 m/sec, so you will end up spending more power than necessary. Further, the base of the Zn metal to be melted is preferably an electroformed Zn plate. The reason for this is that, as mentioned above, the surface area is large (it is extremely uneven and contains many pinholes), so the etching force is greater than that of a normal Zn metal plate, and the electroformed Zn plate is exposed to the high-speed liquid flow. H2 gas adsorbed on the surface of the electroformed Zn plate due to collision with the plate is eliminated,
By promoting the cathode reaction H 2 O + 1/2O 2 +2e→2OH - by supplying air (O 2 ) and air (O 2 ), the normal Zn metal plate (5 mm thick Zn
This is because it can promote the dissolution of Zn metal more markedly than the plate). Furthermore, it is preferable to adjust the plating liquid pH to 0.5 to 2.0 for the following reason. For example, a typical bath composition for plating with an insoluble anode for galvanizing is ZnSO4.7H2O 300-500g/ Na2SO4 30g / Al2 ( SO4 ) 3.17H2O 50g /PH 1-3. It is. In recent years, plating liquid pH 3→1→0.5 has been trending. In promoting the dissolution of Zn metal, what controls the supply rate of zinc ions is H + in the plating solution.
The lower the H + concentration, the higher the metal ion supply rate; however, at pH < 0.5, Pb ions are added to the plating solution due to the dissolution of the insoluble anode (e.g. Pb-Sn5% anode) at the same time as electrolysis. This is because Fe has the disadvantage of being easily eluted and thus deteriorating the properties of the fitted product. At pH > 2, Fe dissolved from the steel plate tends to form Fe(OH) 3 precipitates, and the method of the present invention Even with the electroformed Zn plate used, the dissolution rate of Zn metal decreases, and when trying to obtain a dissolution rate commensurate with the amount of Zn consumed by plating, the amount of liquid per cell (one plating bath) decreases. This is because the required number of fluidized melting devices will increase significantly, construction costs will be high, and it will be impractical. Next, preferred embodiments of the zinc ion supply device of the present invention will be described in more detail. FIG. 1 shows a zinc ion supply device used in the zinc ion supply method of the present invention, which includes a plating bath 1, a liquid flow dissolving device 2, and a circulation tank 4. As shown in FIG. 2, a plurality of electroformed Zn plates 7 are arranged in layers at predetermined intervals in the liquid flow melting device 2, and both sides of the electroformed Zn plates 7 in the longitudinal direction are covered with nets 9 made of metal, plastic, etc. It is surrounded. The direction of the electroformed Zn plate 7 is set in the same direction as the direction of the liquid flowing from the nozzle 5a communicating with the upper part of one side wall of the liquid flow melting device 2 to the nozzle 15a communicating with the lower part of the opposite side wall. The flow is electroforming
It is designed to flow smoothly between the Zn plates 7.
These nozzles 5a and 15a are the pipes 5 and 15a, respectively.
It forms part of 15. The circulation tank 4 has a liquid tank 4a through which the tamping liquid with a reduced zinc ion concentration passes, and a liquid tank 4b through which the tamping liquid with an increased zinc ion concentration passes, and the liquid tank 4a is connected to a pipe 8. , 5 to the plating bath 1 and the liquid fluid dissolving device 2, respectively, and the liquid tank 4b communicates to the plating bath 1 and the liquid fluid dissolving device 2 via pipes 21 and 15, respectively. Then, in the plating bath 1, the plating solution with reduced zinc ion concentration is transferred from the pipe 8 to the liquid tank 4a to the pump 6.
The liquid is sent to the pipe 5→nozzle 5a→liquid flow dissolving device 2 via. In the device 2, the zinc ion concentration of the plating solution increases due to Zn dissolution. This plating liquid with increased zinc ion concentration is supplied again to the plating bath 1 or another plating bath via the nozzle 15a→pipe 15→liquid tank 4b→pipe 21. Note that the nozzles 5a and 15a have a liquid flow rate of 0.5~
In order to maintain the speed at 2.0m/sec, it is set to about 10-30mm x 1000mm. <Example> Using the ion supply device with the above configuration, electroforming
Filled with 50kg of Zn plate (Toho Zinc 1706),
A plating solution was continuously supplied at a flow rate of 0.5 to 2.5 m/sec to promote dissolution of Zn metal, and the dissolution rate was determined. The soaking bath used had the following composition: ZnSO 4 7H 2 O 460 g / Na 2 SO 4 50 g / Al 2 (SO 4 ) 3 17H 2 O 30 g / PH 0.5-2.0 Bath temperature 55-60°C . The results of measuring the amount of Zn metal dissolved under the above conditions are shown in Table 1 and FIGS. 3 and 4. The dissolution of Zn metal is influenced by the shape of Zn metal, the liquid flow rate, and the pH of the plating solution.
It can be seen that the electroformed Zn plate is superior to the Zn plate as a Zn metal. The conditions for application to electric Zn plating were determined from the above plating bath composition, and the validity of the method of the present invention was demonstrated by the following calculations. The amount of Zn consumed in electroplating is, for example, per 1 hour plating with a power supply capacity of 40000A/cell: 40000A/cell/96500C×32.7×60 2 ×1/10 3 ≒50Kg/
It is hr. Therefore, the dissolution efficiency of the electroformed Zn plate is 0.6 (60%)/3hr = 0.2/hr [2] (PH1, liquid flow rate 0.6 to 1.5 m/sec level). 0.6-1.5m/sec level), 0.2 (20%)/3hr = 0.067/hr. For 10hr plating, [1] requires a melting device with 10×50/0.2=2500Kg of Zn metal; [2] requires a melting device with 10×50/0.067=7463Kg of Zn metal. Now, the occupancy efficiency of electroformed Zn plate in liquid flow equipment has been increased to 35%.
Then, the number of liquid flow devices required per 1 cell is [1]: 2.5×10 3 /4.5 (specific gravity of electroformed Zn plate)×1/0.3
5=1.59m3 [ 2 ] becomes 7.5× 103 /4.5 (specific gravity)×1/0.35= 4.76m3 . If the size of the liquid flow device is length L = 1 m, depth (width) W = 1 m, and height H = 2 m, then V = LWH = 2 m 3 Therefore, in [1], 1.59/2 = 0.8 (1 unit) possible) [2
] Then, 4.76/2 = 2.4 (about 2 units is sufficient). However, when a Zn plate is used, the dissolution rate is 1/3 to 1/5 of that of an electroformed Zn plate, so about 4 times as much as the above is required, which proves to be impractical.
【表】
＜発明の効果＞
以上詳述したように本発明によれば、亜鉛の溶
解を液流動方式により、電鋳Zn板を用いること
で溶解促進する効果をあげることができた。
また、、溶解する電鋳亜鉛板は従来法に用いら
れる亜鉛粒、亜鉛小片、通常の亜鉛板よりも安価
であり、電鋳Zn板の装入方法も短時間で可能で
ある。
本発明の液流動溶解装置は従来法のバレル方式
よりも安価であるから、製造コストを大幅に低減
できる。
さらに、従来法では、Zn（OH）2や、スラツジ
の発生大（バレルの網目より金属粒が落下し沈
積）のため、亜鉛イオンが増加しためつき液にこ
れらが混入し、ひいてはめつき浴槽内に運ばれる
危険性を有しているため、めつき品質特性を悪化
させる原因と考えられていたが、電鋳Zn板はほ
ぼ完全に溶解されるため、溶解装置内にスラツジ
として沈積され難く、本発明法ではその危険性が
きわめて小さい。[Table] <Effects of the Invention> As detailed above, according to the present invention, the effect of promoting the dissolution of zinc by using an electroformed Zn plate was achieved by dissolving zinc using a liquid flow method. In addition, the electroformed zinc plate to be melted is cheaper than the zinc grains, zinc pieces, or ordinary zinc plate used in the conventional method, and the method for charging the electroformed Zn plate can be done in a short time. Since the liquid flow dissolving device of the present invention is cheaper than the conventional barrel method, manufacturing costs can be significantly reduced. Furthermore, in the conventional method, large amounts of Zn(OH) 2 and sludge are generated (metal particles fall and deposit through the mesh of the barrel), which increases the zinc ions and mixes into the plating solution, which in turn causes the plating bath to deteriorate. However, since electroformed Zn sheets are almost completely melted, they are less likely to be deposited as sludge inside the melting equipment. However, in the method of the present invention, this risk is extremely small.
第１図は本発明に係る亜鉛イオン供給方法のシ
ステム図である。第２図は液流動溶解装置の一部
切欠斜視図である。第３図および第４図は本発明
法と従来法とZn金属溶解率との関係を示すグラ
フである。第５図および第６図は従来例を示す図
である。
符号の説明、１……めつき浴槽、２……液流動
溶解装置、４……サーキユレーシヨンタンク、
５，８，１５，２１……パイプ（配管系）、５ａ，
１５ａ……ノズル、６……ポンプ、７……電鋳
Zn板。
FIG. 1 is a system diagram of the zinc ion supply method according to the present invention. FIG. 2 is a partially cutaway perspective view of the liquid flow dissolving device. FIGS. 3 and 4 are graphs showing the relationship between the method of the present invention, the conventional method, and the Zn metal dissolution rate. FIGS. 5 and 6 are diagrams showing conventional examples. Explanation of symbols, 1...Plating bathtub, 2...Liquid flow dissolving device, 4...Circulation tank,
5, 8, 15, 21...pipe (piping system), 5a,
15a... Nozzle, 6... Pump, 7... Electroforming
Zn board.
Claims (1)
亜鉛イオン濃度が低下した循環めつき液を電鋳亜
鉛板をめつき液の流れ方向に平行に配置させた溶
解装置内を0.5〜2.5m／秒の流速で通過させて得
た亜鉛イオン濃度の上昇した液を、前記または他
のめつき浴槽に供給することを特徴とする亜鉛系
電気めつきにおける亜鉛イオン供給方法。 ２ 亜鉛系電気めつきを行なうめつき浴槽と、該
めつき浴槽からの亜鉛イオン濃度が低下した循環
めつき液を配管系を経て通過させて該循環めつき
液の亜鉛イオン濃度を上昇させるために電鋳亜鉛
板をめつき液の流れ方向に平行に配設した液流動
溶解装置と、この溶解液を前記または他のめつき
浴槽に導く配管系とを備えることを特徴とする亜
鉛系電気めつきにおける亜鉛イオン供給装置。[Scope of Claims] 1. A circulating plating solution with reduced zinc ion concentration from a plating bath during zinc-based electroplating is placed in a melting device in which an electroformed zinc plate is arranged parallel to the flow direction of the plating solution. 1. A method for supplying zinc ions in zinc-based electroplating, characterized in that a solution with increased zinc ion concentration obtained by passing through the solution at a flow rate of 0.5 to 2.5 m/sec is supplied to the above or other plating bath. 2. To increase the zinc ion concentration of the circulating plating solution by passing through a plating bath in which zinc-based electroplating is performed and the circulating plating solution with a reduced zinc ion concentration from the plating bath through a piping system. A zinc-based electrical system comprising: a liquid flow dissolving device in which an electroformed zinc plate is arranged parallel to the flow direction of the plating solution; and a piping system for guiding the dissolving solution to the above or another plating bath. Zinc ion supply device for plating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1323086A JPS62174400A (en) | 1986-01-24 | 1986-01-24 | Method and apparatus for supplying metallic ion in electroplating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1323086A JPS62174400A (en) | 1986-01-24 | 1986-01-24 | Method and apparatus for supplying metallic ion in electroplating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62174400A JPS62174400A (en) | 1987-07-31 |
| JPH0229760B2 true JPH0229760B2 (en) | 1990-07-02 |
Family
ID=11827381
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1323086A Granted JPS62174400A (en) | 1986-01-24 | 1986-01-24 | Method and apparatus for supplying metallic ion in electroplating |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62174400A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03129446U (en) * | 1990-04-06 | 1991-12-26 |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5463479B2 (en) * | 2012-02-10 | 2014-04-09 | ユケン工業株式会社 | Electric energy and composition manufacturing apparatus, and plating equipment including the apparatus |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58151489A (en) * | 1982-02-27 | 1983-09-08 | Nippon Steel Corp | Iron-zinc alloy plating method |
-
1986
- 1986-01-24 JP JP1323086A patent/JPS62174400A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58151489A (en) * | 1982-02-27 | 1983-09-08 | Nippon Steel Corp | Iron-zinc alloy plating method |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03129446U (en) * | 1990-04-06 | 1991-12-26 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62174400A (en) | 1987-07-31 |
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