JP2004083323A - Nickel nitrite aqueous solution and production method therefor - Google Patents

Nickel nitrite aqueous solution and production method therefor Download PDF

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JP2004083323A
JP2004083323A JP2002245411A JP2002245411A JP2004083323A JP 2004083323 A JP2004083323 A JP 2004083323A JP 2002245411 A JP2002245411 A JP 2002245411A JP 2002245411 A JP2002245411 A JP 2002245411A JP 2004083323 A JP2004083323 A JP 2004083323A
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nitrite
nickel
aqueous solution
concentration
ions
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JP4167030B2 (en
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Yutaka Konose
木ノ瀬 豊
Toru Hatake
畠 透
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Nippon Chemical Industrial Co Ltd
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Nippon Chemical Industrial Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a nickel nitrite aqueous solution which has the reduced content of sodium ions as impurities, does not substantially contain sulfuric acid ions and enables surface treatment for metal with extremely satisfactory efficiency. <P>SOLUTION: As the content of impurities in the solution when the concentration of the nickel nitrite [Ni(NO<SB>2</SB>)<SB>2</SB>] aqueous solution is expressed in terms of 10 wt.% as NO<SB>2</SB>, the concentration of sodium (Na) ions is 200 to 2,000 ppm, and the concentration of sulfuric acid (SO<SB>4</SB>) ions is ≤20 ppm. The nickel nitrite aqueous solution can be produced by using a nickel compound and an alkali nitrite as raw materials, and causing electrolytic synthesis by metathesis reaction with an ion exchange membrane as a diaphragm. <P>COPYRIGHT: (C)2004,JPO

Description

【0001】
【発明の属する技術分野】
本発明は、亜硝酸ニッケル水溶液及びその製造方法に関し、特に極めて効率のよい金属表面処理を可能とし、特に金属の化成処理のクローズドシステム化を可能とすることができる不純物としてナトリウムイオン量が低減され、特に硫酸イオンとカルシウムイオンを実質的に含有しない亜硝酸ニッケル水溶液およびその製造方法 に関するものである。
【0002】
【従来の技術】
亜硝酸ニッケルは、空気中で徐々に加熱すると100℃前後で酸化窒素を出して分解することは知られている。また、該亜硝酸ニッケルは、水に可溶であるが加水分解しやすく、水溶液を蒸発させるとオキシ亜硝酸ニッケル[ NiO・Ni(NO ) ] となることは知られている。
【0003】
係る亜硝酸ニッケルの一般的な製造方法は、硫酸ニッケル溶液と亜硝酸バリウム溶液を混合して、温度を上げることなくろ液を蒸発、濃縮して結晶を得る方法である。(“化学大辞典”昭和59年3月15日、共立出版株式会社発行、参照)
【0004】
しかしながら、この方法は亜硝酸ニッケルと硫酸バリウムの溶解度の差により硫酸バリウムを分離除去する方法であるが、化学的に不安定な亜硝酸バリウムの入手が困難なことや、蒸発、濃縮の操作が必要なことから、工業的にはコストアップの原因となる等の問題点を抱えている。
従って、工業的に高純度の亜硝酸ニッケル又はその水溶液を入手することは困難な状況である。
【0005】
また、一般的に金属表面に塗装を施す際の前処理工程としては、脱脂→水洗→皮膜化成処理→水洗→乾燥の各工程で構成されている。皮膜化成処理の方法の1つとして、鉄鋼の表面にりん酸亜鉛皮膜を形成する処理方法が一般的に採用されており、この目的の皮膜剤として、亜鉛をりん酸に溶解したものを水で希釈して処理液としている。これを「金属表面処理」と称している。
【0006】
さらに、皮膜化成反応を促進するために亜硝酸ソーダ、塩素酸ソーダなどの薬剤を皮膜剤に添加しており、これらを通常は「促進剤」と称している。この促進剤は添加することにより、化成処理温度をより低温でも可能にし、皮膜形成処理時間を短縮する効果がある。
【0007】
ところが、従来の亜硝酸ソーダや塩素酸ソーダなどのソーダ塩は処理浴を長期間使用しているうちにNaイオン濃度が高くなり、その結果処理浴のpHが上昇して化成皮膜の成分が処理浴中に沈澱するという問題を抱えている。また老化した処理液を回収して再生する場合、処理浴中にNaイオンがたまると浴バランスが崩れてしまい、回収した処理液からNaイオンを除去しなければならないという問題がある。通常、Naイオンを含む処理液は、産業廃棄物として処理せざるをえない状況である。
また、近年、金属表面処理液の業界でも環境問題が注目を集めており、処理浴のクローズドシステム化が検討されている。
【0008】
【発明が解決しようとする課題】
このため、従来にもまして、スラッジの発生が少ない金属表面処理方法が検討されている。
本発明者らは、先に硫酸亜鉛と亜硝酸カルシウムを反応させ、次いで精製を行って得られるナトリウムイオンや硫酸イオンを実質的に含まない金属表面処理用皮膜化成促進剤として有用な亜硝酸亜鉛水溶液を提案した(特開2001−323386号)。また、皮膜化成促進剤中にカルシウムイオンが存在すると、例えば、燐酸亜鉛化成処理液と混合した場合に燐酸カルシウムとして表面処理液中でスラッジ化することが知られている。通常、これらのスラッジは、定期的に回収され処理浴中に蓄積しないようにしている。しかしながら、そうしたスラッジの回収操作も煩雑であり、工業的に有利でない。
【0009】
本発明者らは、更に、金属表面処理用皮膜化成促進剤として有用な亜硝酸ニッケル水溶液について研究を重ねた結果、不純物としてのナトリウムイオンが低減され、特に硫酸イオンとカルシウムイオンを実質的に含有しない亜硝酸水溶液を見出した。
【0010】
即ち、本発明は、極めて効率のよい金属の表面処理を可能とする不純物としてのナトリウムイオンが低減され、特に硫酸イオンとカルシウムイオンを実質的に含有しない亜硝酸ニッケル水溶液およびその製造方法を提供することを目的とする。
【0011】
【課題を解決するための手段】
かかる実情において、本発明は、ニッケル化合物と亜硝酸アルカリを原料として、イオン交換膜を隔膜として複分解反応により電解合成して得られる亜硝酸ニッケル水溶液中には、実質的に硫酸イオンと、カルシウムイオンを含まず、ナトリウムイオンも500〜2000ppmとなり、更に、該亜硝酸ニッケル水溶液を金属表面処理用皮膜化成促進剤に用いることにより、スラッジの発生が低減され、極めて効率のよい金属の表面処理が可能となると言う知見に基づいて完成したものである。
【0012】
即ち、本発明の第1の発明は、亜硝酸ニッケル[ Ni(NO )]水溶液の濃度をNO として10重量%で換算したときの溶液中の不純物含有量として、ナトリウム(Na)イオン濃度が200〜2000ppm、且つ硫酸(SO )イオン濃度が20ppm以下であることを特徴とする亜硝酸ニッケル水溶液を提供するものである。
【0013】
また、本発明の第2の発明は、ニッケル化合物と亜硝酸アルカリを原料として、イオン交換膜を隔膜として複分解反応により合成することを特徴とする前記亜硝酸ニッケル水溶液の製造方法を提供するものである。
【0014】
前記反応は、陰極、陽極間を陽イオン交換膜と陰イオン交換膜とを交互に配列することにより1つの濃縮室とそれを挟んだ2つの脱塩室とを有するユニットを備えた電気透析槽で行うものが好ましい。
【0015】
また、前記一方の脱塩室にニッケル化合物水溶液を、他方の脱塩室に亜硝酸アルカリ水溶液を供給し、該脱塩室に挟まれた濃縮室に陽イオン交換膜を通してニッケルイオンを、陰イオン交換膜を通して亜硝酸イオンを導入して亜硝酸ニッケルを得る方法が好ましい。
【0016】
更に、前記亜硝酸ニッケル水溶液に、安定化剤を含有する亜硝酸ニッケル水溶液を提供するものである。
【0017】
前記安定化剤は、亜硝酸アルカリ金属塩、糖類又はキレート剤から選ばれるものである亜硝酸ニッケル水溶液を提供するものである。
【0018】
【発明の実施の形態】
以下、本発明を詳細に説明する。
本発明の亜硝酸ニッケル水溶液は、一般式Ni(NO ) で表される成分とH Oの任意の比率で混合されている溶液である。
【0019】
また、工業的に精製することは、非常に困難な化合物であるけれども本発明に係る亜硝酸ニッケル水溶液は、ナトリウム(Na)イオンが低減され、また硫酸(SO )イオンを実質的に含有しないことにその特徴がある。
【0020】
ここで、水溶液中の亜硝酸ニッケルの濃度は、ニッケル(Ni)イオン濃度と亜硝酸イオン濃度を測定し、Ni(NO ) としての濃度である。ニッケルイオン濃度はICP発光分光法で、また亜硝酸(NO )イオン濃度は、イオンクロマトグラフィー法で求められるものである。
【0021】
また、不純物のナトリウム(Na)イオン、硫酸(SO )イオンは、共にICP発光分光法で求められるものである。なお、硫酸(SO )イオンは、イオウ(S)で測定したものを硫酸イオンに換算したものである。
【0022】
本発明における不純物濃度は、NO として10重量%に換算して算出し、ナトリウムイオンが200〜2000ppm、好ましくは500〜1500ppmであり、硫酸イオンが20ppm以下、好ましくは10ppm以下である。
【0023】
本発明に係る亜硝酸ニッケル水溶液は、亜硝酸イオン濃度が5〜15重量%、好ましくは9〜12重量%、Niイオン濃度が5〜10重量%、好ましくは7〜9重量%であり、Ni(NO ) としての濃度は、10〜25重量%、好ましくは15〜20重量%である。
【0024】
本発明に係る亜硝酸ニッケル水溶液は、ナトリウム(Na)イオン、特に、硫酸(SO )イオン濃度が低減されていることから、これを金属表面処理用皮膜化成促進剤組成物に使用すると極めて効率のよい表面処理システムを設計することができる。
【0025】
次いで、本発明の亜硝酸ニッケル水溶液の製造方法について説明する。
本発明の亜硝酸ニッケル水溶液の製造方法は、ニッケル化合物と亜硝酸アルカリを原料とし、水溶液中でイオン交換膜を隔膜として複分解反応により電解合成することを特徴とするものである。
【0026】
本発明は、好ましくは次のようにして実施される。即ち、陰極、陽極間を陽イオン交換膜と陰イオン交換膜とを交互に配列することにより1つの濃縮室とそれを挟んだ2つの脱塩室とからなるユニットを備えた電気透析槽において、各々の脱塩室はいずれも陽極側を陰イオン交換膜、陰極側を陰イオン交換膜で構成され、一方の陽極側の脱塩室に原料のニッケル化合物水溶液を、他方の陰極側の脱塩室に亜硝酸アルカリ水溶液を供給し、電流を通電することにより、2つの脱塩室に挟まれた濃縮室に陽イオン交換膜を通してニッケルイオンを、陰イオン交換膜を通して亜硝酸イオンを導入して、濃縮室に目的とする亜硝酸ニッケル水溶液を得るものである。
【0027】
ニッケル化合物水溶液は、水溶性のニッケル化合物を水に溶解した水溶液であり、ニッケル化合物としては、例えば、硫酸ニッケル、硝酸ニッケル、塩化ニッケル、炭酸ニッケル、燐酸ニッケル等が挙げられ、これらは、1種又は2種以上で用いられ、この中で工業的に入手しやすく、安価なこと から硫酸ニッケルが好ましい。
【0028】
かかるニッケル化合物の水溶液濃度は、特に制限はないが、好ましくは室温における飽和濃度以下であり、具体的には0.5〜2.0mol/L、好ましくは0.9〜1.3mol/Lである。
【0029】
もう一方の出発原料となる亜硝酸アルカリ水溶液は、水溶性の亜硝酸アルカリを水に溶解した水溶液であり、亜硝酸アルカリとしては、例えば、亜硝酸ナトリウム、亜硝酸カリウム、亜硝酸リチウム等が挙げられ、これらは、1種又は2種以上で用いられ、この中で工業的に入手しやすく、安価なことから亜硝酸ナトリウムが好ましい。
【0030】
かかる亜硝酸アルカリの水溶液濃度は、特に制限はないが、好ましくは室温における飽和濃度以下であり、具体的には、1.5〜6.0mol/L、好ましくは3.0〜4.5mol/Lである。
【0031】
本発明で用いることができる陽イオン交換膜としては、特に制限はなく、例えば、セレミオンCMV(旭硝子社製)、ネオセプタCM−1(徳山曹達社製)、Nafion324(デュポン社製)等が挙げれる。一方、陰イオン交換膜としては、特に制限はなく、セレミオンAMV(旭硝子社製)、ネオセプタAM−1(徳山曹達社製)等が挙げられる。
【0032】
本発明の電気透析槽で使用される陽極および陰極は、用いる原料や電解槽の形状によって適宜材質と形状が定められ、具体的には、白金、鉄、銅、鉛等の金属系や炭素系材料が挙げられる。
【0033】
反応温度は、10〜50℃、好ましくは20〜40℃である。電流密度は1.0A/dm 〜限界電流密度であり、好ましくは1.5〜5.0A/dm である。通電時間は、5〜50時間、好ましくは10〜40時間であるが、必ずしもこれらの条件に限定されるものではない。
【0034】
更に、本発明の亜硝酸ニッケル水溶液の製造方法を図1に示した電気透析槽で実施する場合を詳しく説明する。
図1中の電気透析槽は、陽極側から陰極側へ、陰イオン交換膜(A1)、陽イオン交換膜(C1)、陰イオン交換膜(A2)、陽イオン交換膜(C2)を順次配置し、また、陽極室/脱塩室(I)/濃縮室(I)/脱塩室(II)/陰極室を順次備えた構成からなる。
【0035】
陽極室、陰極室には、NaSO、NaCl、NHBr等の電解質が供給される。また、脱塩室(I)には前記したニッケル化合物水溶液を供給する。一方、脱塩室(II)には、前記した亜硝酸アルカリ水溶液を供給し、電流を通電することにより濃縮室(I)に亜硝酸ニッケル水溶液が製造される。
【0036】
濃縮室(I)で得られる亜硝酸ニッケル水溶液濃度は、通電時間が長くなるほど、亜硝酸ニッケル水溶液濃度が高くなるが、亜硝酸ニッケル[Ni(NO )]水溶液の濃度をNO として10重量%で換算したときの溶液中の不純物として含有されるナトリウムイオン濃度及び硫酸イオン濃度も高くなる傾向があることから、硫酸イオン濃度が20ppm以下、ナトリウムイオン濃度が2000ppm以下の範囲となるように、通電時間を制御することが好ましい。
【0037】
かくすることにより得られる亜硝酸ニッケル水溶液は、亜硝酸イオン濃度が5〜15重量%、好ましくは9〜12重量%、Niイオン濃度が、5〜10重量%、好ましくは7〜9重量%、Ni(NO ) としての濃度が、10〜25重量%、好ましくは15〜20重量%である。
【0038】
また、亜硝酸ニッケル[Ni(NO )]水溶液の濃度をNO として10重量%で換算したときの溶液中の不純物として、ナトリウムイオン濃度が200〜2000ppm、好ましくは500〜1500ppm、硫酸イオン濃度が20pp m以下、好ましくは10ppm以下であることから、本発明の亜硝酸ニッケル水溶液は、金属表面処理用皮膜化成促進剤組成物として使用することができる。
【0039】
また、本発明の亜硝酸ニッケル水溶液の製造方法では、所望の亜硝酸ニッケル濃度の水溶液が得られるが、本発明では、亜硝酸ニッケル[Ni(NO )]水溶液の濃度をNO として10重量%で換算したときの溶液中の不純物として、硫酸イオン濃度が20ppmより大きくなった場合には、所望により、残存する硫酸イオンを除去精製することができる。
【0040】
係る精製方法は、下記のように例えば
▲1▼バリウムイオンを添加して硫酸バリウムとして沈殿させる方法
▲2▼陽イオン又は陰イオン交換樹脂に溶液を通過させる方法
▲3▼溶媒抽出方法
等がある。
【0041】
具体的には、残存する硫酸イオンに対して当量よりも僅かに過剰のバリウムイオンを添加すればよく、具体的には、残存する硫酸イオンに対して1.05〜1.5倍当量、好ましくは1.05〜1.2倍当量である。
【0042】
本発明の係る亜硝酸ニッケル水溶液は、金属表面処理用皮膜化成促進剤又はその組成物として好適に使用することが出来る。かかる皮膜化成促進剤は、皮膜化成反応を促進するために化成処理液に添加して金属表面に化成皮膜を形成させる成分である。
【0043】
この時の化成皮膜は、例えばリン酸亜鉛皮膜、リン酸鉄皮膜、リン酸マンガン皮膜があるが、本発明の亜硝酸ニッケル水溶液を皮膜化成促進剤として用いるのはリン酸亜鉛皮膜が好ましく、本発明の亜硝酸ニッケル水溶液をリン酸亜鉛皮膜に用いる場合、リン酸亜鉛皮膜形成用処理浴の中で、亜硝酸ニッケルの亜硝酸イオンは亜硝酸ソ ーダの亜硝酸イオンと同様な促進効果があり、またニッケルイオンはリン酸亜鉛皮膜の成分であるので、亜硝酸ニッケルはアニオンとカチオンの両方が表面処理用薬剤としてそれぞれの効果を発揮することができる。
【0044】
また、本発明の亜硝酸ニッケル水溶液は、不純物としてのナトリウムイオンが低減され、特に硫酸イオンを実質的に含有しないことから該亜硝酸ニッケル水溶液を金属表面処理用皮膜化成促進剤として用いることにより、スラッジの発生が低減され、金属表面処理のクローズシステム化を意図した場合においても、極めて効率のよい金属の表面処理が期待できる。
【0045】
【実施例】
以下、本発明を実施例により詳細に説明するが、本発明はこれらに限定されるものではない。
【0046】
実施例1
図1に示すような5槽型のイオン交換膜による電気透析装置を使用して、陰イオン交換膜(旭硝子社製;セレミオンAMV)と陽イオン交換膜(旭硝子社製;セレミオンCMV)からそれぞれNO イオンとZnイオンのみを移動させて亜硝酸ニッケル水溶液を得た。なお、実験方法は以下のとおりである。
【0047】
硫酸ニッケル6水塩526gをイオン交換水に溶解して、NiSO で15重量%の水溶液を調製して、脱塩室(I)に入れた。また、亜硝酸ナトリウム600gをイオン交換水に溶解して、NaNO で30重量%の水溶液を調製して脱塩室(II)に入れた。
【0048】
また、濃縮室(I)に亜硝酸ニッケル1.7重量%の水溶液を入れた。陽極室と陰極室にはNaSO3.0重量%の水溶液を入れた。有効膜面積が約120cm の陰イオン交換膜(A1,A2)と陽イオン交換膜(C1,C2)を交互に図1のようにセットして形成した各室の溶液を、各室の溶液濃度を均一性を保つた めに、各々ポンプで循環しながら、各イオン交換膜に5Vの電圧を印加して、イオン交換膜による複分解反応を40時間行って、亜硝酸ニッケル水溶液試料を得た。なお、該亜硝酸ニッケル水溶液の亜硝酸ニッケル濃度が17.7重量%、亜硝酸ニッケル[ Ni(NO )]水溶液の濃度をNO として10重量%で換算したときの溶液中の不純物として、ナトリウムイオン1188ppm、硫酸イオン濃度が10ppmであった。
【0049】
また、透析時間による濃縮室(I)の亜硝酸ニッケル水溶液中のNiイオン濃度、NO イオン濃度の関係及びそれに伴う不純物含有量の関係を表1に示す。
【0050】
【表1】

Figure 2004083323
【0051】
(注)表中のN.D.は検出限界1ppm以下を示す。
【0052】
【発明の効果】
以上説明した様に、本発明の亜硝酸ニッケル水溶液は、不純物としてナトリウムイオン量が低減され、また硫酸イオンが実質的に含有しないことが特徴であり、該亜硝酸ニッケル水溶液を金属表面処理用皮膜化成促進剤として用いて、例えばリン酸亜鉛系の表面処理剤に添加して鉄鋼や亜鉛の表面にリン酸亜鉛皮膜を形成させる場合には、処理浴中に不純物イオンの蓄積が少なく、また、スラッジの発生も低減され、液の交換頻度を大幅に低減できるだけでなく、クローズドシステム化を意図した場合においても、極めて効率のよい金属の表面処理が期待できる。
また、本発明の亜硝酸ニッケル水溶液の製造方法によれば、極めて工業的に有利な方法で、該亜硝酸ニッケル水溶液を製造することができる。
【図面の簡単な説明】
【図1】本発明の亜硝酸ニッケル水溶液の製造方法に用いる電気透析槽を示す概略図である。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an aqueous solution of nickel nitrite and a method for producing the same, in particular, it enables extremely efficient metal surface treatment, and in particular, reduces the amount of sodium ions as an impurity capable of enabling a closed system of chemical conversion treatment of metals. More particularly, the present invention relates to an aqueous solution of nickel nitrite substantially free of sulfate ions and calcium ions and a method for producing the same.
[0002]
[Prior art]
It is known that nickel nitrite decomposes by emitting nitric oxide at about 100 ° C. when gradually heated in air. It is known that nickel nitrite is soluble in water but easily hydrolyzed, and becomes nickel oxynitrite [NiO.Ni (NO 2 ) 2 ] when the aqueous solution is evaporated.
[0003]
A general method for producing such nickel nitrite is a method in which a nickel sulfate solution and a barium nitrite solution are mixed, and the filtrate is evaporated and concentrated without raising the temperature to obtain crystals. (See “Chemical Encyclopedia” published by Kyoritsu Shuppan Co., Ltd. on March 15, 1984)
[0004]
However, although this method separates and removes barium sulfate due to the difference in solubility between nickel nitrite and barium sulfate, it is difficult to obtain chemically unstable barium nitrite, and evaporation and concentration operations are difficult. Since it is necessary, there is a problem that the cost is increased industrially.
Therefore, it is difficult to industrially obtain high-purity nickel nitrite or an aqueous solution thereof.
[0005]
In general, a pretreatment step for applying a coating to a metal surface includes the steps of degreasing, washing with water, coating conversion, washing with water, and drying. As one of the film conversion treatment methods, a treatment method of forming a zinc phosphate film on the surface of steel is generally adopted. As a film-forming agent for this purpose, a solution obtained by dissolving zinc in phosphoric acid with water is used. Dilute to make a processing solution. This is called "metal surface treatment".
[0006]
Further, chemicals such as sodium nitrite and sodium chlorate are added to the film agent in order to promote the film formation reaction, and these are usually called "promoter". By adding this accelerator, there is an effect that the chemical conversion treatment temperature can be lowered even more and the film formation treatment time is shortened.
[0007]
However, conventional sodium salts, such as sodium nitrite and sodium chlorate, have a high Na ion concentration during prolonged use of the treatment bath, and as a result, the pH of the treatment bath rises and the components of the chemical conversion film are treated. It has the problem of settling in the bath. Further, when recovering and regenerating an aged processing solution, there is a problem that if Na ions accumulate in the processing bath, the bath balance is lost, and Na ions must be removed from the recovered processing solution. Normally, the treatment liquid containing Na ions must be treated as industrial waste.
In recent years, environmental issues have also attracted attention in the metal surface treatment liquid industry, and a closed system of a treatment bath is being studied.
[0008]
[Problems to be solved by the invention]
For this reason, a metal surface treatment method with less generation of sludge has been studied more than ever.
The present inventors have made zinc nitrite useful as a film formation accelerator for metal surface treatment substantially free of sodium ions and sulfate ions, obtained by first reacting zinc sulfate with calcium nitrite and then performing purification. An aqueous solution was proposed (JP-A-2001-323386). It is also known that when calcium ions are present in the film formation promoting agent, for example, when mixed with a zinc phosphate conversion treatment solution, sludge is formed in the surface treatment solution as calcium phosphate. Usually, these sludges are collected periodically to prevent accumulation in the treatment bath. However, the operation of collecting such sludge is complicated and not industrially advantageous.
[0009]
The present inventors further conducted research on an aqueous solution of nickel nitrite useful as a film formation accelerator for metal surface treatment, and as a result, sodium ions as impurities were reduced, and in particular, substantially contained sulfate ions and calcium ions. No nitrous acid solution was found.
[0010]
That is, the present invention provides a nickel nitrite aqueous solution in which sodium ions as impurities enabling extremely efficient metal surface treatment are reduced, and in particular, substantially does not contain sulfate ions and calcium ions, and a method for producing the same. The purpose is to:
[0011]
[Means for Solving the Problems]
Under such circumstances, the present invention provides a nickel nitrite aqueous solution obtained by electrolytically synthesizing a nickel compound and alkali nitrite as raw materials by a double decomposition reaction using an ion exchange membrane as a membrane, and substantially contains sulfate ions and calcium ions. And sodium ions are also in the range of 500 to 2,000 ppm, and by using the nickel nitrite aqueous solution as a film formation accelerator for metal surface treatment, sludge generation is reduced, and extremely efficient metal surface treatment is possible. It was completed based on the finding that
[0012]
That is, the first invention of the present invention provides sodium (Na) ion as an impurity content in a solution of a nickel nitrite [Ni (NO 2 ) 2 ] aqueous solution when the concentration of the solution is converted into NO 2 by 10% by weight. A nickel nitrite aqueous solution characterized by having a concentration of 200 to 2000 ppm and a sulfate (SO 4 ) ion concentration of 20 ppm or less.
[0013]
Further, the second invention of the present invention provides a method for producing the above-mentioned aqueous solution of nickel nitrite, characterized by using a nickel compound and an alkali nitrite as raw materials and synthesizing by a double decomposition reaction using an ion exchange membrane as a diaphragm. is there.
[0014]
The reaction is performed by arranging a cation exchange membrane and an anion exchange membrane alternately between a cathode and an anode, and an electrodialysis tank including a unit having one enrichment chamber and two desalination chambers sandwiching the enrichment chamber. Is preferably performed.
[0015]
Further, a nickel compound aqueous solution is supplied to the one desalting chamber, and an alkali nitrite aqueous solution is supplied to the other desalting chamber. A preferred method is to introduce nitrite ions through an exchange membrane to obtain nickel nitrite.
[0016]
Further, the present invention provides a nickel nitrite aqueous solution containing a stabilizer in the nickel nitrite aqueous solution.
[0017]
The stabilizer provides an aqueous solution of nickel nitrite, which is selected from alkali metal nitrites, sugars and chelating agents.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The nickel nitrite aqueous solution of the present invention is a solution in which a component represented by the general formula Ni (NO 2 ) 2 and H 2 O are mixed at an arbitrary ratio.
[0019]
Although it is a compound that is extremely difficult to purify industrially, the aqueous solution of nickel nitrite according to the present invention has reduced sodium (Na) ions and does not substantially contain sulfate (SO 4 ) ions. In particular, there is a characteristic.
[0020]
Here, the concentration of nickel nitrite in the aqueous solution is a concentration as Ni (NO 2 ) 2 by measuring nickel (Ni) ion concentration and nitrite ion concentration. The nickel ion concentration is determined by ICP emission spectroscopy, and the nitrite (NO 2 ) ion concentration is determined by ion chromatography.
[0021]
Further, sodium (Na) ion and sulfuric acid (SO 4 ) ion as impurities are both obtained by ICP emission spectroscopy. The sulfuric acid (SO 4 ) ion is a value obtained by converting sulfur (S) into sulfuric acid.
[0022]
The impurity concentration in the present invention is calculated by converting the content of NO 2 into 10% by weight, and the content of sodium ion is 200 to 2000 ppm, preferably 500 to 1500 ppm, and the content of sulfate ion is 20 ppm or less, preferably 10 ppm or less.
[0023]
The aqueous solution of nickel nitrite according to the present invention has a nitrite ion concentration of 5 to 15% by weight, preferably 9 to 12% by weight, a Ni ion concentration of 5 to 10% by weight, preferably 7 to 9% by weight. The concentration of (NO 2 ) 2 is 10 to 25% by weight, preferably 15 to 20% by weight.
[0024]
Since the aqueous solution of nickel nitrite according to the present invention has a reduced concentration of sodium (Na) ions, particularly sulfuric acid (SO 4 ) ions, it is extremely efficient to use it in a film formation accelerator composition for metal surface treatment. A good surface treatment system can be designed.
[0025]
Next, the method for producing an aqueous solution of nickel nitrite of the present invention will be described.
The method for producing an aqueous solution of nickel nitrite of the present invention is characterized in that a nickel compound and an alkali nitrite are used as raw materials, and electrolytic synthesis is performed by a double decomposition reaction in an aqueous solution using an ion exchange membrane as a membrane.
[0026]
The present invention is preferably implemented as follows. That is, an electrodialysis tank provided with a unit consisting of one concentrating chamber and two desalting chambers sandwiching the concentrating chamber by alternately arranging a cation exchange membrane and an anion exchange membrane between the cathode and the anode. Each of the desalting chambers is composed of an anion exchange membrane on the anode side and an anion exchange membrane on the cathode side.The raw material nickel compound aqueous solution is placed in one anode side desalination chamber, and the other cathode side is desalted. An alkaline nitrite aqueous solution is supplied to the chamber, and a current is applied to introduce nickel ions through a cation exchange membrane and nitrite ions through an anion exchange membrane into a concentration chamber sandwiched between two desalting chambers. And an intended nickel nitrite aqueous solution is obtained in a concentration chamber.
[0027]
The nickel compound aqueous solution is an aqueous solution obtained by dissolving a water-soluble nickel compound in water. Examples of the nickel compound include nickel sulfate, nickel nitrate, nickel chloride, nickel carbonate, nickel phosphate, and the like. Alternatively, two or more kinds are used, and among them, nickel sulfate is preferable because it is industrially easily available and inexpensive.
[0028]
The concentration of the nickel compound in the aqueous solution is not particularly limited, but is preferably equal to or lower than the saturation concentration at room temperature, and specifically 0.5 to 2.0 mol / L, preferably 0.9 to 1.3 mol / L. is there.
[0029]
The alkali nitrite aqueous solution that is the other starting material is an aqueous solution obtained by dissolving a water-soluble alkali nitrite in water, and examples of the alkali nitrite include sodium nitrite, potassium nitrite, and lithium nitrite. These are used alone or in combination of two or more. Among them, sodium nitrite is preferable because it is industrially easily available and inexpensive.
[0030]
The concentration of the aqueous solution of the alkali nitrite is not particularly limited, but is preferably equal to or lower than the saturation concentration at room temperature, specifically, 1.5 to 6.0 mol / L, and preferably 3.0 to 4.5 mol / L. L.
[0031]
The cation exchange membrane that can be used in the present invention is not particularly limited, and examples thereof include Selemion CMV (manufactured by Asahi Glass Co., Ltd.), Neosepta CM-1 (manufactured by Tokuyama Soda Co., Ltd.), and Nafion 324 (manufactured by DuPont). . On the other hand, there is no particular limitation on the anion exchange membrane, and examples thereof include Selemion AMV (manufactured by Asahi Glass Co., Ltd.) and Neosepta AM-1 (manufactured by Tokuyama Soda Co., Ltd.).
[0032]
The anode and cathode used in the electrodialysis cell of the present invention are appropriately determined in material and shape depending on the raw material used and the shape of the electrolytic cell. Specifically, platinum, iron, copper, metal such as lead, and carbon-based Materials.
[0033]
The reaction temperature is 10 to 50C, preferably 20 to 40C. The current density is 1.0 A / dm 3 to the limit current density, and preferably 1.5 to 5.0 A / dm 3 . The energization time is 5 to 50 hours, preferably 10 to 40 hours, but is not necessarily limited to these conditions.
[0034]
Further, the case where the method for producing an aqueous solution of nickel nitrite of the present invention is carried out in the electrodialysis tank shown in FIG. 1 will be described in detail.
In the electrodialysis tank in FIG. 1, an anion exchange membrane (A1), a cation exchange membrane (C1), an anion exchange membrane (A2), and a cation exchange membrane (C2) are sequentially arranged from the anode side to the cathode side. In addition, it has a configuration in which an anode chamber / desalting chamber (I) / concentrating chamber (I) / desalting chamber (II) / cathode chamber is sequentially provided.
[0035]
An electrolyte such as Na 2 SO 4 , NaCl, and NH 4 Br is supplied to the anode chamber and the cathode chamber. The above-mentioned nickel compound aqueous solution is supplied to the desalting chamber (I). On the other hand, the above-mentioned aqueous solution of alkali nitrite is supplied to the desalting chamber (II), and an electric current is applied to produce an aqueous solution of nickel nitrite in the concentration chamber (I).
[0036]
The concentration of the aqueous solution of nickel nitrite obtained in the concentration chamber (I) is such that the longer the energizing time, the higher the concentration of the aqueous solution of nickel nitrite, but the concentration of the aqueous solution of nickel nitrite [Ni (NO 2 ) 2 ] is 10% as NO 2. Since the sodium ion concentration and the sulfate ion concentration contained as impurities in the solution in terms of% by weight tend to be high, the sulfate ion concentration is set to 20 ppm or less and the sodium ion concentration is set to 2000 ppm or less. It is preferable to control the energization time.
[0037]
The aqueous solution of nickel nitrite thus obtained has a nitrite ion concentration of 5 to 15% by weight, preferably 9 to 12% by weight, a Ni ion concentration of 5 to 10% by weight, preferably 7 to 9% by weight, the concentration of the Ni (NO 2) 2, 10~25 wt%, preferably from 15 to 20 wt%.
[0038]
In addition, when the concentration of the aqueous solution of nickel nitrite [Ni (NO 2 ) 2 ] is converted to NO 2 by 10% by weight, the concentration of sodium ion as an impurity in the solution is 200 to 2000 ppm, preferably 500 to 1500 ppm, and sulfate ion. Since the concentration is 20 ppm or less, preferably 10 ppm or less, the aqueous solution of nickel nitrite of the present invention can be used as a film formation accelerator composition for metal surface treatment.
[0039]
In the manufacturing method of the nitrite aqueous solution of nickel of the present invention, although an aqueous solution of the desired nitrite nickel concentration is obtained, in the present invention, the concentration of nitrite nickel [Ni (NO 2) 2] aqueous solution as NO 2 10 If the concentration of sulfate ion as an impurity in the solution in terms of% by weight is greater than 20 ppm, the remaining sulfate ion can be removed and purified as desired.
[0040]
Such purification methods include, for example, (1) a method of adding barium ions to precipitate as barium sulfate, (2) a method of passing a solution through a cation or anion exchange resin, and (3) a solvent extraction method. .
[0041]
Specifically, barium ions may be added in a slightly excess amount relative to the remaining sulfate ions, and specifically, 1.05 to 1.5 times equivalent to the remaining sulfate ions, preferably Is 1.05 to 1.2 times equivalent.
[0042]
The nickel nitrite aqueous solution according to the present invention can be suitably used as a film formation accelerator for metal surface treatment or a composition thereof. Such a film formation accelerator is a component that is added to a chemical conversion treatment solution to promote a film formation reaction and forms a chemical conversion film on a metal surface.
[0043]
The chemical conversion film at this time includes, for example, a zinc phosphate film, an iron phosphate film, and a manganese phosphate film. When the aqueous solution of nickel nitrite of the present invention is used for a zinc phosphate film, the nitrite ion of nickel nitrite has the same promoting effect as the nitrite ion of soda nitrite in the treatment bath for forming a zinc phosphate film. In addition, since nickel ions are components of the zinc phosphate coating, nickel nitrite can exert its respective effects as surface treatment chemicals using both anions and cations.
[0044]
In addition, the aqueous solution of nickel nitrite of the present invention has a reduced sodium ion as an impurity, and in particular, since the aqueous solution of nickel nitrite is substantially free of sulfate ions, by using the aqueous solution of nickel nitrite as a film formation accelerator for metal surface treatment, Even when sludge generation is reduced and a closed system of metal surface treatment is intended, extremely efficient metal surface treatment can be expected.
[0045]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.
[0046]
Example 1
Using an electrodialyzer with a five-tank type ion exchange membrane as shown in FIG. An aqueous solution of nickel nitrite was obtained by transferring only two ions and Zn ions. The experimental method is as follows.
[0047]
526 g of nickel sulfate hexahydrate was dissolved in ion-exchanged water, and a 15% by weight aqueous solution was prepared with NiSO 4 and placed in the desalting chamber (I). Further, 600 g of sodium nitrite was dissolved in ion-exchanged water, and a 30% by weight aqueous solution was prepared with NaNO 2 and placed in the desalting chamber (II).
[0048]
Further, an aqueous solution of 1.7% by weight of nickel nitrite was put in the concentration chamber (I). An aqueous solution containing 3.0% by weight of Na 2 SO 4 was placed in the anode compartment and the cathode compartment. The solution in each chamber formed by alternately setting the anion exchange membranes (A1, A2) and the cation exchange membranes (C1, C2) having an effective membrane area of about 120 cm 2 as shown in FIG. In order to maintain the uniformity of the concentration, a voltage of 5 V was applied to each ion exchange membrane while circulating with a pump, and the double decomposition reaction by the ion exchange membrane was performed for 40 hours to obtain a nickel nitrite aqueous solution sample. . Incidentally, nitrite nickel concentration of 17.7 wt% of nitrous nickel nitrate aqueous solution, as an impurity in the solution when the concentration of nitrite nickel [Ni (NO 2) 2] aqueous solution was converted at 10% by weight NO 2 , Sodium ion of 1188 ppm and sulfate ion concentration of 10 ppm.
[0049]
Table 1 shows the relationship between the concentration of Ni ions and the concentration of NO 2 ions in the aqueous solution of nickel nitrite in the concentration chamber (I) according to the dialysis time, and the relationship between the contents of impurities associated therewith.
[0050]
[Table 1]
Figure 2004083323
[0051]
(Note) N. in the table D. Indicates a detection limit of 1 ppm or less.
[0052]
【The invention's effect】
As described above, the aqueous solution of nickel nitrite of the present invention is characterized in that the amount of sodium ions as impurities is reduced, and that the aqueous solution of nickel nitrite is substantially free of sulfate ions. When used as a chemical conversion accelerator, for example, when added to a zinc phosphate-based surface treatment agent to form a zinc phosphate film on the surface of steel or zinc, the accumulation of impurity ions in the treatment bath is small, and The generation of sludge is also reduced, and not only can the frequency of liquid exchange be significantly reduced, but also in the case of a closed system, extremely efficient metal surface treatment can be expected.
Further, according to the method for producing an aqueous solution of nickel nitrite of the present invention, the aqueous solution of nickel nitrite can be produced by an extremely industrially advantageous method.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an electrodialysis tank used in the method for producing an aqueous solution of nickel nitrite of the present invention.

Claims (7)

亜硝酸ニッケル[ Ni(NO )]水溶液の濃度をNO として10重量%で換算したときの溶液中の不純物含有量として、ナトリウム(Na)イオン濃度が200〜2000ppmで、且つ硫酸(SO )イオン濃度が20ppm以下であることを特徴とする亜硝酸ニッケル水溶液。When the concentration of the aqueous solution of nickel nitrite [Ni (NO 2 ) 2 ] is converted to NO 2 by 10% by weight, the sodium (Na) ion concentration is 200 to 2000 ppm and the sulfuric acid (SO 4 ) An aqueous nickel nitrite solution having an ion concentration of 20 ppm or less. ニッケル化合物と亜硝酸アルカリを原料として、イオン交換膜を隔膜として複分解反応により合成することを特徴とする請求項1記載の亜硝酸ニッケル水溶液の製造方法。2. The method for producing an aqueous solution of nickel nitrite according to claim 1, wherein the compound is synthesized by a double decomposition reaction using a nickel compound and alkali nitrite as raw materials and using an ion exchange membrane as a membrane. 前記反応は、陰極、陽極間を陽イオン交換膜と陰イオン交換膜とを交互に配列することにより1つの濃縮室とそれを挟んだ2つの脱塩室とを有するユニットを備えた電気透析槽で行うことを特徴とする請求項2記載の亜硝酸ニッケル水溶液の製造方法。The reaction is carried out by alternately arranging a cation exchange membrane and an anion exchange membrane between a cathode and an anode. The method for producing an aqueous solution of nickel nitrite according to claim 2, wherein 前記一方の脱塩室にニッケル化合物水溶液を、他方の脱塩室に亜硝酸アルカリ水溶液を供給し、該脱塩室に挟まれた濃縮室に陽イオン交換膜を通して亜鉛イオンを、陰イオン交換膜を通して亜硝酸イオンを導入して亜硝酸ニッケルを得ることを特徴とする請求項2又は3記載の亜硝酸ニッケル水溶液の製造方法。A nickel compound aqueous solution is supplied to one of the desalting chambers and an alkali nitrite aqueous solution is supplied to the other desalting chamber. Zinc ions are passed through a cation exchange membrane to a concentration chamber sandwiched between the desalting chambers, and an anion exchange membrane is provided. The method for producing an aqueous solution of nickel nitrite according to claim 2 or 3, wherein nickel nitrite is obtained by introducing nitrite ions through the process. 前記ニッケル化合物が硫酸ニッケルであり、亜硝酸アルカリが亜硝酸ナトリウムであることを特徴とする請求項2乃至4のいずれかの項に記載の亜硝酸ニッケル水溶液の製造方法。The method for producing an aqueous solution of nickel nitrite according to any one of claims 2 to 4, wherein the nickel compound is nickel sulfate and the alkali nitrite is sodium nitrite. 更に、安定化剤を含有する請求項1記載の亜硝酸ニッケル水溶液。The nickel nitrite aqueous solution according to claim 1, further comprising a stabilizer. 前記安定化剤は、亜硝酸アルカリ金属塩、糖類又はキレート剤から選ばれるものである請求項6記載の亜硝酸ニッケル水溶液。The nickel nitrite aqueous solution according to claim 6, wherein the stabilizer is selected from an alkali metal nitrite, a saccharide, and a chelating agent.
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Publication number Priority date Publication date Assignee Title
CN113000836A (en) * 2021-03-08 2021-06-22 昆明理工大学 Nickel coating surface treatment method for NaCl particles

Cited By (2)

* Cited by examiner, † Cited by third party
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CN113000836A (en) * 2021-03-08 2021-06-22 昆明理工大学 Nickel coating surface treatment method for NaCl particles
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