JP2011132553A - Method for electrolytically eluting platinum and electrolytic treatment apparatus - Google Patents
Method for electrolytically eluting platinum and electrolytic treatment apparatus Download PDFInfo
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本発明は、電解により白金を溶出させる方法に関し、これにより、白金の１０ｍｇ単位の重量調整を行う方法に関する。 The present invention relates to a method for eluting platinum by electrolysis, and thereby relates to a method for adjusting the weight of platinum in units of 10 mg.
白金は、その化学的特性や電気的特性から、触媒・各種電極等の工業的用途で多様に使用されているが、それらに加えて、希少性のある貴金属であることから、資産的な用途も古くから知られている。この白金の資産的な利用形態としては、インゴット・コインバー等に成形したものの売買によるのが一般的である。 Platinum is used in a variety of industrial applications such as catalysts and various electrodes due to its chemical and electrical characteristics, but in addition to these, it is a rare noble metal, so it is used as an asset. Has been known for a long time. In general, the platinum is used in the form of assets such as buying and selling ingots, coin bars and the like.
白金コインバーは、その重量が表面に表示されており、地金時価と当該表示重量との関係で価値が変動するものであるから、表示重量と実重量との乖離は回避されるべきものである。特に、製造元の信用確保のため、実重量が表示重量より小さくなることは許されるものではない。 Since the weight of the platinum coin bar is displayed on the surface and the value fluctuates depending on the relationship between the market price of the metal and the displayed weight, the difference between the displayed weight and the actual weight should be avoided. . In particular, the actual weight is not allowed to be smaller than the displayed weight in order to ensure the manufacturer's trust.
コインバーの製造は、白金地金原料を溶解・鋳造して成形するものであり、複雑なものではないが、上記のような重量管理が肝要であり、地金原料の秤量を厳密に行うと共に、成形後の重量調整が必要となる。これまでのコインバーの製造において、この重量調整の方法としては、機械的研摩によりコインバーを削って、実重量が表示重量より僅か（ミリグラムオーダー程度）に大きくなるように調整している。 Coin bars are manufactured by melting and casting platinum bullion raw material, which is not complicated, but weight management as described above is essential, and the bullion raw material is precisely weighed, It is necessary to adjust the weight after molding. In the manufacture of conventional coin bars, the weight adjustment method is such that the actual weight is slightly larger than the displayed weight (on the order of milligrams) by scraping the coin bar by mechanical polishing.
しかし、機械的研摩による重量調整は、その精度を作業者の熟練に頼る傾向があり、効率的なものではない。また、機械的研摩は熟練者が行っても、常に適正になされるとは限らずに、ときとして削りすぎにより実重量が表示重量を下回ることもある。このような場合、そのコインバーは製品として扱うことができないために歩留まりを悪化させ、全体の製造コストを圧迫することとなる。 However, the weight adjustment by mechanical polishing tends to rely on the skill of the operator for accuracy, and is not efficient. Further, even if the mechanical polishing is performed by an expert, it is not always performed properly, and sometimes the actual weight may be lower than the indicated weight due to excessive cutting. In such a case, since the coin bar cannot be handled as a product, the yield is deteriorated and the entire manufacturing cost is pressed.
一方、高精度且つ効率的な重量調整の手法として、化学的溶解により重量を減少させる方法も考えられる。ただ、白金は化学的に極めて安定な金属であり、これを溶解できる溶液は、王水或いは王水をベースとしたエッチング液（特許文献１）程度しかない。また、化学的溶解は、一旦溶解反応を開始させると、その制御が容易ではないため、白金を過剰に溶解させるおそれがあり、１０ｍｇ単位の高精度の重量調整は困難である。 On the other hand, a method of reducing the weight by chemical dissolution is also conceivable as a highly accurate and efficient technique for weight adjustment. However, platinum is a chemically very stable metal, and the only solution that can dissolve it is aqua regia or an etching solution based on aqua regia (Patent Document 1). In addition, once chemical dissolution is started, it is not easy to control the chemical reaction, so that platinum may be excessively dissolved, and high-precision weight adjustment in units of 10 mg is difficult.
そこで本発明は、白金を重量調整のため溶出する方法であって、効率的でありながら高精度のものを提供する。また、この方法に基づいた白金の溶出装置も開示する。 Therefore, the present invention provides a method for eluting platinum for weight adjustment, which is efficient but highly accurate. Also disclosed is an apparatus for eluting platinum based on this method.
本発明者等は、上記課題を解決すべく、電解法による白金溶出を検討した。電解法は、所定の電解液中で白金を電極として通電したときの電気化学反応に基づくものであるが、溶解反応は通電時にのみ進行することから、反応の制御が容易である。また、種々の電解条件による溶解量を予め検定しておけば、所望の溶解量に対して精度良く溶解させることができる。従って、電解法は、本願のような微妙な重量調整においても有効であるといえる。 In order to solve the above-mentioned problems, the present inventors examined platinum elution by an electrolytic method. The electrolysis method is based on an electrochemical reaction when electricity is supplied with platinum as an electrode in a predetermined electrolytic solution. However, since the dissolution reaction proceeds only when electricity is supplied, the reaction can be easily controlled. In addition, if the amount of dissolution under various electrolysis conditions is tested in advance, the desired amount of dissolution can be accurately dissolved. Therefore, it can be said that the electrolysis method is effective in the delicate weight adjustment as in the present application.
もっとも、白金は、一般的な電解作業（めっき、水溶液電解等）における陽極材料として用いられる程、電気化学的にも安定な金属である。そのため、電解が効率的であったとしても、容易に溶出させることはできないと考えられる。本発明者等は、白金を電解法により溶出させる条件についての電解液、電解条件（温度、電流密度）を鋭意検討し、本発明に想到した。 However, platinum is an electrochemically stable metal as it is used as an anode material in general electrolysis operations (plating, aqueous electrolysis, etc.). Therefore, even if electrolysis is efficient, it cannot be easily eluted. The inventors of the present invention diligently studied the electrolytic solution and electrolytic conditions (temperature, current density) for eluting platinum by an electrolysis method, and came up with the present invention.
即ち、本発明は、電解液中で白金を電極として電解することで白金を溶出させる電解溶出方法であって、前記電解液は、錯化剤として３〜１０重量％のモノエタノールアミンを含む、５〜１５重量％の水酸化ナトリウム溶液であり、電解条件として、液温２５〜６０℃、電流密度１００〜１４０Ａ／ｄｍ２の交流電流を印加して前記白金電極を溶出させる方法である。 That is, the present invention is an electrolytic elution method for eluting platinum by electrolyzing platinum in an electrolytic solution as an electrode, and the electrolytic solution contains 3 to 10% by weight of monoethanolamine as a complexing agent. This is a 5 to 15% by weight sodium hydroxide solution, and the platinum electrode is eluted by applying an alternating current having a liquid temperature of 25 to 60 ° C. and a current density of 100 to 140 A / dm 2 as electrolysis conditions.
本発明は、白金の電解溶出のための電解液として、水酸化ナトリウム溶液を用い、その濃度及び液温、並びに電解時の電流密度を所定範囲に制限する。これらの数値範囲は、白金の溶解量をできるだけ大きいものとするためである。また、本発明では、電解液にモノエタノールアミンを錯化剤として添加することを要する。錯化剤添加を必須とするのは、錯化剤のない状態で電解を行うと、一旦溶出した白金が再度電極に付着し、電解の進行を妨げるためであり、溶出した白金を電解液中で安定化させる必要があるからである。また、本発明における白金の電解は、交流電流を印加するものであり、直流電流の印加では白金の溶出は生じない。 In the present invention, a sodium hydroxide solution is used as an electrolytic solution for the electrolysis of platinum, and its concentration and liquid temperature, and the current density during electrolysis are limited to a predetermined range. These numerical ranges are for making the dissolution amount of platinum as large as possible. In the present invention, it is necessary to add monoethanolamine as a complexing agent to the electrolytic solution. The addition of a complexing agent is essential because, when electrolysis is performed in the absence of a complexing agent, once eluted platinum adheres to the electrode again, preventing the progress of electrolysis. This is because it is necessary to stabilize it. In addition, the electrolysis of platinum in the present invention applies an alternating current, and the application of a direct current does not cause elution of platinum.
本発明に係る白金の電解溶出について、他の条件について説明すると、白金の対極としては、ステンレス、グラファイト、バルブ金属（チタン、ニオブ、タンタル）の他、白金も有用である。そして、本発明が高濃度のアルカリ溶液を使用すること、及び、電解溶出させた電解液の後処理（白金回収）の容易さを考慮すると、耐腐食性の良好なバルブ金属、白金を対極とするのが好ましい。 Regarding other conditions for the electrolytic elution of platinum according to the present invention, platinum is also useful as a counter electrode of platinum, in addition to stainless steel, graphite, and valve metals (titanium, niobium, tantalum). And considering that the present invention uses a high-concentration alkaline solution and the ease of post-treatment (platinum recovery) of the electrolytic solution that has been electrolyzed, the valve metal with good corrosion resistance, platinum is used as the counter electrode. It is preferable to do this.
また、電解時の電極間距離は、特に限定する必要はないが、３０ｍｍ以上が好ましく、５０ｍｍ以上がより好ましい。尚、電極間距離の上限は、電解電圧低減の理由から、１００ｍｍ以下とするのが好ましい。 Moreover, the distance between electrodes at the time of electrolysis does not need to be specifically limited, but 30 mm or more is preferable and 50 mm or more is more preferable. In addition, it is preferable that the upper limit of the distance between electrodes shall be 100 mm or less from the reason of the electrolytic voltage reduction.
本発明では、上記範囲内で電解条件（電解液の温度、濃度、電流密度）を所定値に設定し、それらに基づき電解時間を設定することで白金の溶出量を制御することができる。電解時間の設定は、電解条件おける電流効率と所望の白金溶出量とから計算することができる。ここで、電流効率とは、印加した電力（電流）に対し、実際に白金の溶出反応に消費された電力である。電流効率は、予め実験的に種々の電解条件における白金溶出量を測定することで電解条件毎に設定される。 In the present invention, the elution amount of platinum can be controlled by setting the electrolysis conditions (electrolyte temperature, concentration, current density) to predetermined values within the above ranges and setting the electrolysis time based on them. The setting of the electrolysis time can be calculated from the current efficiency under the electrolysis conditions and the desired platinum elution amount. Here, the current efficiency is the power actually consumed in the elution reaction of platinum with respect to the applied power (current). The current efficiency is set for each electrolysis condition by experimentally measuring the platinum elution amount under various electrolysis conditions in advance.
ところで、上記のように電解時間を設定して電解を行っても、ごく微量ではあるが、所望量の白金が溶出しないおそれがある。これは、電解液の温度管理や印加電流の安定化（定電流化）を図っても、電解液の濃度及び温度、電流密度は電解中に僅かながら変化することを完全に回避することは困難であり、これら電解条件の変化は白金溶出量にズレを生じさせることなる。この白金溶出量のズレは僅かなものであるが、本発明において調整する白金溶出量は微量であることを考慮すれば無視できないものである。 By the way, even if the electrolysis is carried out by setting the electrolysis time as described above, there is a possibility that a desired amount of platinum may not be eluted although it is very small. This is because it is difficult to completely prevent the electrolyte concentration, temperature, and current density from changing slightly during electrolysis, even if the temperature of the electrolyte is controlled and the applied current is stabilized (constant current). These changes in the electrolysis conditions cause a deviation in the platinum elution amount. Although the deviation of the platinum elution amount is slight, it is not negligible considering that the platinum elution amount to be adjusted in the present invention is very small.
そこで、本発明では、電解中の電解条件の変化に応じて電解時間を調整することで、所望の白金溶出量を達成させることが好ましい。この電解時間の調整は、電解中における電解条件を逐次測定し、測定値に基づき電解効率を補正して電解時間を調整する。具体的には、電解開始時の電解液の液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値に基づき基準電流効率Ｅ０を設定し、電解中、一定時間間隔Δｔで電解液の液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値を測定し、測定された液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値の各値に基づき前記基準電流効率Ｅ０を補正して実効電流効率Ｅｓを算出し、前記実効電流効率Ｅｓから、白金の所要溶出量に応じた電解時間Ｔを算出した後、それまでの累積測定時間（ΣΔｔ）と前記電解時間Ｔとを対比してＴ≦ΣΔｔとなるまで電解を継続するものである。 Therefore, in the present invention, it is preferable to achieve the desired platinum elution amount by adjusting the electrolysis time according to the change in electrolysis conditions during electrolysis. In the adjustment of the electrolysis time, electrolysis conditions during electrolysis are sequentially measured, and the electrolysis time is adjusted by correcting the electrolysis efficiency based on the measured value. Specifically, the reference current efficiency E 0 is set based on the electrolyte temperature at the start of electrolysis, the sodium hydroxide concentration, the monoethanolamine concentration, and the applied current value. The liquid temperature, sodium hydroxide concentration, monoethanolamine concentration, and applied current value were measured, and the reference current efficiency E 0 was based on the measured liquid temperature, sodium hydroxide concentration, monoethanolamine concentration, and applied current value. calculates the effective current efficiency E s correction to the said from the effective current efficiency E s, after calculating the required elution volume electrolysis time corresponding to T of platinum, the electrolysis time and the cumulative measurement time (ΣΔt) until it Contrast with T, electrolysis is continued until T ≦ ΣΔt.
基準電流効率Ｅ０は、上記の通り、種々の電解条件で実験的に測定することで予備的に設定可能なものである。そして、電解中に電解条件に変動が生じないのであれば、この基準電流効率から単純に電解時間を算定することができるが、電解中の電解条件の変動は不可避であることを考慮した補正が必要となる。そこで、本発明では、電解開始から一定時間間隔Δｔで電解液の液温等を測定し、その測定値に基づき基準電流効率Ｅ０を補正して実効電流効率Ｅｓを算出する。そして、実効電流効率Ｅｓに基づいて、白金の所要溶出量に応じた電解時間Ｔを改めて算出する。この電解時間Ｔは、その電解条件測定時における所要電解時間であるが、これも測定毎に変動するものである。そこで、本発明では、最新の測定時まで累積測定時間（ΣΔｔ）がその段階における電解時間Ｔに超えているか否かを判定しつつ電解を継続し、Ｔ≦ΣΔｔとなった時点で所要溶解量に達したと判断し電解を中断する。 As described above, the reference current efficiency E 0 can be set in advance by experimental measurement under various electrolysis conditions. If the electrolysis conditions do not change during electrolysis, the electrolysis time can be simply calculated from this reference current efficiency, but correction considering the fact that the electrolysis conditions change during electrolysis is inevitable. Necessary. Accordingly, the present invention measures the electrolyte liquid temperature etc. at regular time intervals Δt from the start of electrolysis, it calculates the effective current efficiency E s by correcting the reference current efficiency E 0 on the basis of the measured value. Then, based on the effective current efficiency E s, which recalculates the electrolysis time T corresponding to the required amount of elution of platinum. This electrolysis time T is a required electrolysis time at the time of measuring the electrolysis conditions, and this also varies with each measurement. Therefore, in the present invention, electrolysis is continued while determining whether or not the cumulative measurement time (ΣΔt) exceeds the electrolysis time T at that stage until the latest measurement, and when T ≦ ΣΔt, the required dissolution amount The electrolysis is interrupted.
以上のような電流効率の補正を加えた電解時間調整のプロセスは、電解装置においてプログラム化が可能である。そこで、本発明に対応した電解装置としては、電解液を収容する電解槽、電力供給手段を備える通常の電解処理装置に、電解時における水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値を測定する測定手段と、前記測定手段により測定された液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値の各値に基づき基準電流効率Ｅ０を補正して実効電流効率Ｅｓを算出し、白金の所要溶出量に応じた電解時間Ｔを算出すると共に、累積測定時間（ΣΔｔ）と前記電解時間Ｔとを対比しＴ≦ΣΔｔとなるまで電解を継続する制御手段と、を付加したものが提案できる。 The process for adjusting the electrolysis time with the correction of the current efficiency as described above can be programmed in the electrolysis apparatus. Therefore, as an electrolysis apparatus corresponding to the present invention, an electrolytic cell containing an electrolytic solution and a normal electrolysis processing apparatus having a power supply means are used to measure sodium hydroxide concentration, monoethanolamine concentration, and applied current value during electrolysis. The effective current efficiency E s is calculated by correcting the reference current efficiency E 0 based on the measuring means for measuring and the liquid temperature, sodium hydroxide concentration, monoethanolamine concentration, and applied current value measured by the measuring means. And a control means for calculating the electrolysis time T according to the required amount of elution of platinum, and comparing the cumulative measurement time (ΣΔt) with the electrolysis time T and continuing electrolysis until T ≦ ΣΔt. Can be proposed.
尚、上記した電流効率の補正を行なうことで、白金溶出量の精密な制御を行うことができるが、より正確な溶出量制御を行うため、電解処理装置に白金電極の計量手段を設置しても良い。この場合、例えば、所要溶出量の９割を上記のような電流効率の補正をしつつ電解し、その後電解を一時停止して白金電極を計量手段にて計量し、測定された白金重量から実際の溶出量を測定し、これを基に電解時間を再計算することとなる。尚、この計量手段としては、精密天秤等が好ましい。 In addition, by correcting the current efficiency as described above, it is possible to perform precise control of the platinum elution amount. However, in order to perform more precise control of the elution amount, a platinum electrode measuring means is installed in the electrolytic treatment apparatus. Also good. In this case, for example, 90% of the required elution amount is electrolyzed while correcting the current efficiency as described above, and then the electrolysis is temporarily stopped and the platinum electrode is measured by the measuring means, and the actual weight is measured from the measured platinum weight. The amount of elution is measured, and the electrolysis time is recalculated based on this. As the measuring means, a precision balance or the like is preferable.
以上説明したように、本発明によれば、化学的に安定であり容易に溶解できない白金を効率的に溶解させることができる。そして、これにより白金の重量調整高精度に行うことができる。 As described above, according to the present invention, platinum that is chemically stable and cannot be easily dissolved can be efficiently dissolved. Thus, the weight adjustment of platinum can be performed with high accuracy.
以下、本発明の好適な実施形態を説明する。本実施形態では、白金を電極とて種々の電解条件で電解処理を行い、電解条件と白金溶出量（電流効率）との関係を検討した。ここでの電解試験は、電解層として４０ｍｍ×９４ｍｍ×１００ｍｍの電解液体積を有する無隔膜電解槽を用い、白金電極（４５×１００ｍｍ、厚さ０．８ｍｍ）を浸漬した（浸漬長さ８０ｍｍ）。対極にも同じ白金板を用いた。また、電解電源として交流変圧器電源（定格出力３０Ｖ×３０Ａ）を使用した。尚、電解中は電解槽をマグネットスターラー攪拌装置の温浴内に設置し、電解液の攪拌と温度調節を行った。
Hereinafter, preferred embodiments of the present invention will be described. In this embodiment, electrolytic treatment was performed under various electrolysis conditions using platinum as an electrode, and the relationship between the electrolysis conditions and the platinum elution amount (current efficiency) was examined. The electrolysis test here uses a diaphragm membrane electrolytic cell having an electrolyte volume of 40 mm × 94 mm × 100 mm as an electrolytic layer, and a platinum electrode (45 × 100 mm, thickness 0.8 mm) is immersed (
実施例１：まず、水酸化ナトリウム濃度による影響を検討した。電解液として２．５〜２０重量％の水酸化ナトリウム溶液を用いた。ここでの他の電解条件は、電解液温度６０℃、電流密度１１０Ａ／ｄｍ２とした。また、電解前後の白金電極の質量変化を白金溶出量とし、これをファラデーの式をもとに電流効率に換算して評価した。図１は、その結果を示す。図１から、電解液である水酸化ナトリウムの濃度は、少なくとも５重量％以上としなければ電解溶出の効果が生じない。また、濃度を高くすれば良いというものではなく、１５重量％を超えると電流効率が低下する。よって、水酸化ナトリウム濃度は５から１５重量％とすることが好ましいことが確認された。 Example 1 First, the influence of sodium hydroxide concentration was examined. A 2.5 to 20% by weight sodium hydroxide solution was used as the electrolyte. The other electrolysis conditions here were an electrolyte temperature of 60 ° C. and a current density of 110 A / dm 2 . Moreover, the mass change of the platinum electrode before and after electrolysis was defined as the platinum elution amount, and this was evaluated by converting it to current efficiency based on the Faraday equation. FIG. 1 shows the results. From FIG. 1, the electrolytic elution effect does not occur unless the concentration of sodium hydroxide as the electrolytic solution is at least 5% by weight or more. Moreover, it is not a matter of increasing the concentration. If the concentration exceeds 15% by weight, the current efficiency is lowered. Therefore, it was confirmed that the sodium hydroxide concentration is preferably 5 to 15% by weight.
実施例２：次に、電解液（水酸化ナトリウム溶液）の温度による影響を検討した。電解液として１０重量％の水酸化ナトリウム溶液を電解液として、これを５０〜７５℃に保持して電解した。電流密度は１１０Ａ／ｄｍ２とした。評価方法は実施例１と同様である。この結果を図２に示すが、電解液温度については、その上昇に従い電流効率が低下する傾向にある。特に、６０℃を超えると下限に収束する。そこで、電解液温度については６０℃以下にするのが好ましい。また、下限については、温度制御の容易さを考慮し室温程度とするのが好ましく２５℃とするのが好ましい。 Example 2 Next, the influence of the temperature of the electrolytic solution (sodium hydroxide solution) was examined. 10% by weight sodium hydroxide solution was used as the electrolytic solution, and this was maintained at 50 to 75 ° C. for electrolysis. Current density was set to 110A / dm 2. The evaluation method is the same as in Example 1. The results are shown in FIG. 2, and the current efficiency tends to decrease as the electrolyte temperature increases. In particular, when it exceeds 60 ° C., it converges to the lower limit. Therefore, the electrolyte temperature is preferably 60 ° C. or lower. Further, the lower limit is preferably about room temperature in view of ease of temperature control, and is preferably 25 ° C.
実施例３：ここでは、電流密度と電流効率との関係を検討した。電解液として１０重量％の水酸化ナトリウム溶液を電解液として、これを５０℃に保持して電解した。電流密度は７０〜１５５Ａ／ｄｍ２とした。評価方法は実施例１と同様である。この結果を図３に示す。これによると、電流密度についても、適正範囲があり、１００〜１４０Ａ／ｄｍ２の範囲内とするのが好ましい。 Example 3 Here, the relationship between current density and current efficiency was examined. 10% by weight sodium hydroxide solution was used as the electrolytic solution as the electrolytic solution, and this was maintained at 50 ° C. for electrolysis. Current density was 70~155A / dm 2. The evaluation method is the same as in Example 1. The result is shown in FIG. According to this, for the current density, there is a proper range, preferably within the range of 100~140A / dm 2.
実施例４：更に、錯化剤添加の要否及びその濃度について検討した。まず、一般的な錯化剤を各種添加した電解液を使用し、電解試験を行った（水酸化ナトリウム濃度１０重量％、電解液温度４５℃、電流密度１１０Ａ／ｄｍ２）。その結果を表１に示す。
Example 4 : Further, the necessity of adding a complexing agent and its concentration were examined. First, an electrolytic test was performed using an electrolytic solution to which various general complexing agents were added (
表１から、電解液に錯化剤を添加するとしてもどのようなものでも良いというわけではなく、エタノールアミンを適用することが好ましいことがわかる。 From Table 1, it can be seen that even if a complexing agent is added to the electrolytic solution, it does not necessarily have to be added, and it is preferable to apply ethanolamine.
そこで、次に、エタノールアミンの添加量について検討した。上記と同じ電解液、電解条件とし、エタノールアミンの添加量を変化させて電流効率を評価した。図４はその結果を示すものであるが、モノエタノールアミンは３重量％以上の添加がなければ顕著な効果を示すことがないことがわかる。一方、１０％を超えても効果さほどの差はない。よって、モノエタノールアミンの添加量としては３〜１０重量％とすることが好ましい。 Then, next, the addition amount of ethanolamine was examined. The current efficiency was evaluated by changing the addition amount of ethanolamine under the same electrolytic solution and electrolysis conditions as above. FIG. 4 shows the results. It can be seen that monoethanolamine does not show a significant effect unless 3 wt% or more is added. On the other hand, even if it exceeds 10%, there is not much difference. Therefore, the addition amount of monoethanolamine is preferably 3 to 10% by weight.
本発明は、本来、溶解が困難な白金を制御可能な状態で溶解することができる。本発明は、白金の重量の微調整に好適であり、例えば、白金コインバー製造の最終工程に適用できる。
In the present invention, platinum that is inherently difficult to dissolve can be dissolved in a controllable state. The present invention is suitable for fine adjustment of the weight of platinum, and can be applied, for example, to the final process of manufacturing a platinum coin bar.
Claims (6)
前記電解液は、錯化剤として３〜１０重量％のモノエタノールアミンを含む、５〜１５重量％の水酸化ナトリウム溶液であり、
電解条件として、液温２５〜６０℃、電流密度１００〜１４０Ａ／ｄｍ２の交流電流を印加して前記白金電極を溶出させる方法。 An electrolytic elution method for eluting platinum by electrolyzing platinum in an electrolyte solution,
The electrolyte is a 5-15 wt% sodium hydroxide solution containing 3-10 wt% monoethanolamine as a complexing agent;
A method of eluting the platinum electrode by applying an alternating current having a liquid temperature of 25 to 60 ° C. and a current density of 100 to 140 A / dm 2 as electrolysis conditions.
電解中、一定時間間隔Δｔで電解液の液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値を測定し、測定された液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値の各値に基づき前記基準電流効率Ｅ０を補正して実効電流効率Ｅｓを算出し、
前記実効電流効率Ｅｓから、白金の所要溶出量に応じた電解時間Ｔを算出した後、それまでの累積測定時間（ΣΔｔ）と前記電解時間Ｔとを対比してＴ≦ΣΔｔとなるまで電解を継続する請求項１〜請求項３のいずれかに記載の白金の電解溶出方法。 Based on the electrolyte temperature at the start of electrolysis, sodium hydroxide concentration, monoethanolamine concentration, applied current value, the reference current efficiency E 0 is set,
During electrolysis, the electrolyte temperature, sodium hydroxide concentration, monoethanolamine concentration, and applied current value were measured at regular time intervals Δt, and the measured solution temperature, sodium hydroxide concentration, monoethanolamine concentration, and applied current value were measured. corrects the reference current efficiency E 0 based on the values of the calculated effective current efficiency E s, the
The electrolyte from the effective current efficiency E s, until after calculating the required elution volume electrolysis time corresponding to T platinum, and T ≦ Shigumaderutati by comparison with the electrolysis time T and the cumulative measurement time (ΣΔt) until it The method for electrolytically eluting platinum according to any one of claims 1 to 3, wherein:
電解時における水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値を測定する測定手段と、
前記測定手段により測定された液温、水酸化ナトリウム濃度、モノエタノールアミン濃度、印加電流値の各値に基づき基準電流効率Ｅ０を補正して実効電流効率Ｅｓを算出し、白金の所要溶出量に応じた電解時間Ｔを算出すると共に、累積測定時間（ΣΔｔ）と前記電解時間Ｔとを対比しＴ≦ΣΔｔとなるまで電解を継続する制御手段と、を備える電解処理装置。 An electrolytic treatment apparatus used in the electrolytic dissolution method of platinum according to claim 4,
Measuring means for measuring sodium hydroxide concentration, monoethanolamine concentration, applied current value during electrolysis,
Said measuring means measured liquid temperature, the sodium hydroxide concentration, calculates the effective current efficiency E s by correcting the reference current efficiency E 0 based on the values of monoethanolamine concentration, applied current value, the required dissolution of platinum An electrolysis apparatus comprising: a control unit that calculates an electrolysis time T according to the amount and continues electrolysis until the accumulated measurement time (ΣΔt) and the electrolysis time T are compared and T ≦ ΣΔt.
The electrolytic processing apparatus according to claim 5, further comprising a measuring unit for measuring the electrolyzed platinum electrode.
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| JP2008285764A (en) * | 1994-03-14 | 2008-11-27 | Umicore Ag & Co Kg | Electrochemical reduction of metal salt as method of preparing highly dispersed metal colloid and substrate fixed metallic cluster by electrochemical reduction of metal salt |
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| JPH06280076A (en) * | 1992-12-18 | 1994-10-04 | Carl Zeiss:Fa | Method for electrolytic dissolution of platinum, platinum impurity and/or platinum alloy |
| JP2008285764A (en) * | 1994-03-14 | 2008-11-27 | Umicore Ag & Co Kg | Electrochemical reduction of metal salt as method of preparing highly dispersed metal colloid and substrate fixed metallic cluster by electrochemical reduction of metal salt |
| WO2008111735A1 (en) * | 2007-03-15 | 2008-09-18 | Eui-Sik Yoon | Method for producing colloidal solution of metal nano-particle and metal nano-particle thereby |
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