JP4557565B2

JP4557565B2 - Electrolyzer

Info

Publication number: JP4557565B2
Application number: JP2004037468A
Authority: JP
Inventors: 孝之島宗; 公吉川
Original assignee: Asahi Glass Co Ltd; Kinotech Solar Energy Corp
Current assignee: Kinotech Solar Energy Corp; AGC Inc
Priority date: 2004-01-15
Filing date: 2004-01-15
Publication date: 2010-10-06
Anticipated expiration: 2024-01-15
Also published as: JP2005200759A

Description

本発明は、主として塩化亜鉛電解など溶融塩電解を行い、主として、陽極よりガスを発生させ、陽極より発生するガスを回収すると共に、陰極にて生成する主として融体金属からなる、電解生成物を得る為の電解装置に関するものである。 The present invention mainly performs molten salt electrolyte such as zinc chloride electrolysis, primarily, to generate a gas from the anode, while recovering the gas generated from the anode, consisting mainly melts metals generated in the cathode, the electrolysis products The present invention relates to an electrolytic device for obtaining.

塩化物法によるチタンやシリコンの製造ではチタンやシリコンの塩化物を金属で還元してチタンやシリコン金属を得ると共に、還元用の金属が金属塩化物として取り出され、電気分解によって塩素と金属とし、塩素は粗製チタンや粗製シリコンの塩素化に使われ、金属がそれらの還元精製用としてリサイクルして再使用されている。また近年アルミニウムの精錬として、従来行われていた氷晶石、酸化アルミニウムの電解に代わり低温での電解が可能であり、大幅に消費エネルギーを下げることができる塩化アルミニウムの電解精錬が試みられている。ここではアルミニウム派生品として取り出される塩素は原料である塩化アルミニウムを製造するのに使用される。 With obtaining the titanium or silicon metal by reducing the chloride of titanium or silicon in the metal in the production of titanium and silicon by the chloride process, the metal for the reduction is taken out as a metal chloride, a chlorine and a metal by electrolysis, Chlorine is used for chlorination of crude titanium and crude silicon, and metals are recycled and reused for their reduction and purification. As refining of the recent aluminum, cryolite has been performed conventionally, is capable of electrolysis in place low temperature electrolysis of aluminum oxide, an attempt is greatly electrorefining aluminum chloride is Ru can be reduced energy consumption Yes. Here the chlorine that is picked as an aluminum derived products used to produce aluminum chloride which is a raw material.

このように金属塩化物の塩素と金属との分離は溶融塩の電解によって行われる。たとえば、いわゆるクロル法と呼ばれるチタンの場合は還元剤として塩化マグネシウムが使用されるが、塩化マグネシウムを加熱し溶融塩として、陽極には炭素、陰極には炭素または金属を用い、電解によって陽極では塩素を発生、また陰極ではマグネシウムを得るようにしている。この場合、塩化マグネシウムの融点は７１４℃である一方で、マグネシウムの融点が６４８．８℃であり、添加物なしで電解を行う場合は、溶融塩化マグネシウムをそのまま電解するのであれば、その融点以上の温度、通常はその粘性を考慮すると融点の少なくとも５０℃から１００℃程度高い温度での電解が必要であり、最低７５０℃程度の電解温度が必要になる。ところがマグネシウムは６５０℃以上であれば融体として取り出せるので、電解温度を下げるためにアルカリ金属を加えて共融体としマグネシウムの融点近くまで温度を下げて電解を行っている。これには温度を下げることで取り扱いが容易になること、省エネルギー化が図れるといった利点もある。またより大きな理由としては高温では塩化マグネシウム蒸気の揮散が大きいことで、これが原料のロスとなるばかりか、配管の閉塞、製品の品質の劣化という問題に繋がるということも挙げられる。しかしながら実際にはこのように添加物を入れて融点を下げての電解を行っても、配管部分では塩化マグネシウムの除去を行う必要があった。一方塩化亜鉛では塩化亜鉛自身の融点が２８３℃と非常に低く、製品である亜鉛金属の融点が４１３℃であるので、連続的に安定に亜鉛金属を融体として得るためには電解温度は必然的に４１３℃以上となるため、共融物質を加える必要が無くなるが、その一方で、塩化亜鉛の融点より１００℃以上高い温度、実際には電解質の電気伝導度や粘性係数を考えると２００℃以上高い、５００℃から５５０℃での電解が必要であり、電解それ自身より発生する塩化亜鉛ガス、並びに塩化亜鉛蒸気並びにミストの揮散に対する対策が十分にとれないといった事象が起こり工業的に電解が行われたとことはなかった。また塩化アルミニウムの電解は、アルミニウム精錬の省エネルギー化を目的として種々の検討が行われているが、この場合は塩化ナトリウムに５％程度塩化アルミニウムを加えて電解質として７００℃程度つまりアルミニウムが融体として得られ
る最小限の温度で電解を行っている。これも塩化アルミニウムの融点が１９０℃程度と低く、アルミニウムの融点が６６０℃とそれと比較して遥かに高いために塩化アルミニウム蒸気の影響が大きくてそのままでは電解ができないことに依るのである。これらの電解ではできれば不純物の原因となる補助電解質を入れたくないのであるが、このように入れざるを得ない状況になっているのである。 In this way, separation of metal chloride chlorine and metal is performed by electrolysis of molten salt. For example, although in the case of titanium, so-called chlorine method magnesium chloride is used as the reducing agent, as a molten salt heating magnesium chloride, the anode used carbon, the cathode carbon or metal, the chlorine at the anode by electrolysis In addition, magnesium is obtained at the cathode. In this case, while the melting point of magnesium chloride is 714 ° C., a melting point of magnesium 648.8 ° C., when performing electrolysis without additives, if directly electrolyzing the molten magnesium chloride, its melting point or higher In view of the temperature of this , usually the viscosity, electrolysis is required at a temperature at least about 50 ° C. to 100 ° C. higher than the melting point, and an electrolysis temperature of at least about 750 ° C. is required. However, since magnesium can be taken out as a melt at 650 ° C. or more, in order to lower the electrolysis temperature, an alkali metal is added to form a eutectic so that the temperature is lowered to a temperature close to the melting point of magnesium for electrolysis. Be easily handled by lowering the temperature to, Ru advantages say energy saving can be achieved mower. The more the main reason that the high temperature greater volatilization of magnesium chloride vapor, which is not only a raw material loss, clogging of piping, Ru also mentioned that leads to a problem that the quality of the product deteriorates. However, in practice, even when the electrolysis was performed with the additive added and the melting point lowered, it was necessary to remove the magnesium chloride in the piping portion. On the other hand, in zinc chloride, the melting point of zinc chloride itself is very low at 283 ° C, and the melting point of zinc metal, which is a product, is 413 ° C. Therefore, in order to obtain zinc metal as a melt continuously, the electrolysis temperature is inevitable. Therefore, there is no need to add a eutectic substance, but on the other hand, a temperature that is higher than the melting point of zinc chloride by 100 ° C. or more, actually 200 ° C. considering the electric conductivity and viscosity coefficient of the electrolyte. or higher, is required electrolysis at 550 ° C. from 500 ° C., zinc chloride gas generated from the electrolytic itself, and occur events say measures can not be sufficiently taken for volatilization of zinc chloride vapor and mist industrially Electrolysis was never performed. Various studies have been made on the electrolysis of aluminum chloride for the purpose of energy saving in aluminum refining. In this case, about 5% aluminum chloride is added to sodium chloride, and the electrolyte is about 700 ° C., that is, aluminum is melted. Electrolysis is performed at the minimum temperature that can be obtained. It is also low as the melting point of about 190 ° C. Aluminum chloride, as compared melting point of aluminum 660 ° C. and it greatly affects the aluminum chloride vapors to much higher as it is to due to inability to electrolysis. I do not want to put the auxiliary electrolyte cause if possible impurities in these electrolysis, but it has become a situation where not obtained in this way put forced to.

塩化マグネシウム電解に関しては、特開平０９−００３６８２号公報に見られるが、ここでは電解質として塩化マグネシウムに加えて塩化カリウム、塩化ナトリウムを加えたものを使用し、電解によってマグネシウムを生成させ、それを溶融マグネシウム合金カソード層に取り込み、それを更に電解することによって純電解マグネシウムを得る技術が示されている。ところが現実として問題となる塩化マグネシウムガスや塩化マグネシウムミストによる汚染やパイプの閉塞に対する対策や除去技術は全く示されていない。また特開２００３−３０６７８９号公報では同じく塩化マグネシウムの電解方法に関するものではあるが、電解マグネシウム中に混入している溶融塩の低減について述べており、やはり電解時に発生するガスやミストの除去技術については示されていない。一方本発明者等は塩化亜鉛に注目して種々の検討を行っており、例えば特開２００３−２９３１８１号公報では隔膜付きでしかも多数の電極を並べて塩化亜鉛の電解を行う方法並びに条件を示しており、特開２００３−３１８１７３号公報では電解生成物の陽極分、陰極分を無隔膜でも十分に分けられるようにするために電極を僅かに傾斜させて電解を行い、生成物を電極表面に沿わせて電極部分から引き離す技術を示している。しかし電解時に生成する塩化亜鉛ガスやミストに対する対策は殆ど示されていない。実際の所は電解質に補助電解質を加えて融点を下げて電解を行うような条件では電解温度が電解質単体の融点より低くなり、その場合は電解質の蒸気やミストの問題は無くなる。しかし塩化亜鉛の様な電解生成物の融点が電解質温度より１００℃以上高い場合には、電解生成物より更に高い温度で電解を行わなければならず、このような場合は補助電解質の使用は考えにくいと共に、電解質そのものの蒸気及びミストが時として多量に発生してしまう。これらに対しての対策は従来ほとんど考えられておらず、むしろそのようなケースでの電解は行わないというのが現状のようである。
つまり、特開平０９−００３６８２号公報では塩化マグネシウムの電解に関して電解質として塩化マグネシウムに加えて塩化カリウム、塩化ナトリウムを加えることが示されており、マグネシウムをマグネシウム合金中に生成させ、それを電解することによって純マグネシウムを得ることが示されている特開２００３−３０６７８９号公報では電解は電解ではあるが電解生成物中に残留する電解質の低減について述べている。一方塩化亜鉛電解技術に関する特開２００３−２９３１８１号公報では純塩化亜鉛を電解するが、電極間距離を小さくし、隔膜を付けた電解方法に付いて示しており、また特開２００３−３１８１７３号公報では極間を小さくしたままで効率良く電解を行う方法が述べられている。しかしながら何れの文献でも、電解技術では問題となる発生ガス中への電解質の混入並びに配管の閉塞などに対する技術的な開示は全くなかった。 With respect to the magnesium chloride electrolysis, but seen in JP-A-09-003682, where in addition to the magnesium chloride as an electrolyte of potassium chloride, using what sodium chloride was added, to produce the magnesium by electrolysis, melting it A technique for obtaining pure electrolytic magnesium by incorporating it into a magnesium alloy cathode layer and further electrolyzing it is shown. However, no countermeasures or removal techniques for contamination and pipe clogging due to magnesium chloride gas and magnesium chloride mist, which are problems in practice, are shown. There is also a the related electrolytic method also magnesium chloride in 2003-306789 and JP but has described the reduction of the molten salt is mixed into the electrolytic magnesium, also for removing art gas and mist generated during electrolysis Is not shown. Meanwhile the present inventors has conducted various studies by paying attention to zinc chloride, shows a method and conditions for the electrolysis of zinc chloride by arranging Patent a conditioned membrane in JP 2003-293181 Moreover multiple electrodes For example and has the anode component of 2003-318173 discloses the electrolysis products JP performs electrolysis electrodes is slightly inclined in order to be classified fully in the cathode component of the diaphragm-free, product of the electrode surface This shows the technique of pulling it away from the electrode part. However, there are hardly any countermeasures against zinc chloride gas and mist generated during electrolysis. In fact the electrolyte temperature is lower than the melting point of the electrolyte alone in conditions that perform electrolysis to lower the melting point by adding an auxiliary electrolyte in the electrolyte, in which case the electrolyte vapor or mist problem that a no. However, if the melting point of such electrolysis products of zinc chloride is high 100 ° C. or higher than the electrolyte temperature must be carried out electrolysis at a higher temperature than the electrolysis products, the use of such a case the auxiliary electrolyte is considered It is difficult and sometimes vapor and mist of the electrolyte itself are generated in large quantities. Conventionally, almost no countermeasure has been considered for these, and it seems that the electrolysis in such a case is not performed .
That is, it in addition to the magnesium chloride as an electrolyte with respect to the electrolysis of magnesium chloride in JP-A 09-003682 discloses potassium chloride, sodium chloride has been shown to add, which is produced magnesium in the magnesium alloy, the electrolysis it the electrolyte in JP 2003-306789 JP has been shown that to obtain the pure magnesium is in electrolysis but describes the reduction of the electrolyte remaining in the electrolysis products by. Meanwhile although electrolysis of pure zinc chloride in JP 2003-293181 Laid-related zinc chloride electrolysis technology, the distance between electrodes is reduced, is shown attached to the electrolysis method with a diaphragm, also JP 2003-318173 JP Describes a method of performing electrolysis efficiently while keeping the gap between the electrodes small. However, in any of the documents, there has been no technical disclosure regarding the mixing of the electrolyte into the generated gas and the blockage of the piping, which are problems in the electrolysis technique.

本発明は、溶融金属塩化物から電解により塩素と金属を得るに当たり、できるだけ低い電解温度を保持し、低い電解電圧での電解を行いながら、溶融金属塩化物の蒸発と金属塩化物ミストの生成とを最小限とする電解装置を得ることを目的とする。 The present invention, in obtaining the chlorine and metals by electrolysis from a molten metal chloride, Wherever possible low electrolyte temperature was maintained, while electrolysis at low electrolysis voltage, molten evaporated metal chlorides mist of a metal chloride an object is to obtain an electrolytic device you minimize the generation of.

本発明は、電解槽に配された少なくとも一組の陽極及び陰極の間の電解部分で溶融金属塩化物に電気分解を行い、前記陽極で塩素ガスを得ると共に前記陰極で融体金属を得る電解装置において、直立的に置かれた前記少なくとも一組の陽極及び陰極を含む電極構造体を有し、前記電極構造体の上下部分を、生成される前記塩素ガス及び前記融体金属の排出
並びに電解質である前記溶融金属塩化物の供給を妨げないように開口部とし、前記電極構造体の横部分を、前記少なくとも一組の陽極及び陰極の配列が見えないように表面を囲って前記電解部分の温度を前記電解槽の温度よりも高温に保持自在である保温材として前記電極構造体の一部と成し、前記電極構造体が、前記電解質である前記溶融金属塩化物中に完全に浸漬されることを特徴とする溶融塩電解装置であり、電極を直立させておき、電解ガス、電解生成金属の排出並びに電解質の供給を電極構造体の上下から行うようにし、電極構造体の電解ガス及び電解生成金属の排出並びに電解質の供給用の口である上下を解放したまま周囲を囲み、電解に伴われる発生熱を集中的に電解部分に保持して実電解温度を周囲の温度より高く保持し、電解質（液）の液抵抗を小さく保持すると共に電解質表面では電解質温度が低いために電解質の揮散を最小とし、しかも発生ガスも電解質中を比較的遅い速度で上昇させることができ、ミストやガスとしての電解質の揮発を最少限とすることができると共に、実電解温度を高くして低い電解電圧で電解を行うことができるようになった。
以下詳細に説明する。 The present invention performs electrolysis molten metal chloride in an electrolytic portion between at least one set of an anode and a cathode disposed in the electrolytic bath to obtain a melt metal in the cathode with obtaining chlorine gas in the anolyte in the device, an upright manner said he location has a collector electrode structure including at least one set of anode and cathode, the discharge of the chlorine gas and the melt metal upper and lower portions of the electrode structure, it is generated
And opening so as not to interfere with the supply of the parallel beauty an electrolyte wherein a molten metal chloride, wherein the lateral portion of the electrode structure, wherein at least one set of an anode and array of cathode surrounds the surface to be invisible The temperature of the electrolysis part is formed as a part of the electrode structure as a heat insulating material that can be maintained at a temperature higher than the temperature of the electrolytic cell, and the electrode structure is in the molten metal chloride that is the electrolyte. is completely immersed in the molten salt electrolysis apparatus according to claim Rukoto, allowed to erect the electrode, electrolytic gas, so as to supply the exhaust as well as the electrolyte of the electrolyte-forming metal from the upper and lower electrode structure, the electrode structure surrounds the opened state vertically a mouth for the supply of discharge and the electrolyte of the electrolytic gas and electrolyte-forming metal body, around to the actual electrolysis temperature kept in intensive electrolysis part generated heat accompanied the electrolyte higher holding than the temperature, The electrolyte resistance is kept low and the electrolyte temperature is low on the electrolyte surface, so the volatilization of the electrolyte is minimized, and the generated gas can be raised through the electrolyte at a relatively slow rate. the electrolyte volatilization as co to be able to most small limited, it has become possible to perform the electrolysis at high to low electrolysis voltage actual electrolytic temperature.
This will be described in detail below.

溶融金属塩化物の電解に当たっては陽極より塩素が、陰極では金属が生成する。本発明ではこのような電解の為の電極を直立的に置き、複数の電極からなる電極構造体の周囲を上下部分を除いて囲ってしまう。つまり通常直立的に電極を並べる方法としては一定の電極間距離を置いて複数個の電極を並行に並べ、それらに通電できるようにする。電極の並べ方はいわゆる複極式として複数の電極を並べ両端の電極から通電することにより内部の電極は片面が陽極、他の片面が陰極として働き、実質的に電極間の隙間の数だけ電解槽を直列に接続したのと同じ効果になる電極接続と、単極式として複数の電極の並びで隣同士が互いに陰極、陽極とした電極配置との何れでも良い。このように配置された電極で電解を行う場合、通常必要とする電解電圧の外に、電解質中に電気を流すのに要するいわゆる電気抵抗分と溶融塩電解の場合は殆ど考えなくても良いが電極の過電圧とがあり、これによって電解電圧が決まる。これらの構成電圧の内、電解反応に要する電圧分を除き後は熱となるので本発明の電解装置のように電極の周辺を保温材となるセラミックスなどで囲むことよって電解部分を周辺より高温に保ち、少なくとも電解部分では電解質の粘性が下がり発生ガスや生成金属排出をスムースにでき、また電解質液に温度差による比重差を生じ電解部分の電解質の液流が活発になるという事象が起こり、より安定に電解が進むようになる。このための電極周辺を囲む保温材はその目的を達成できれば特に指定されないが、通常の電解温度は４００℃以上となること、また溶融塩は腐食性の場合が多いことを考慮すること、また絶縁体であることが望ましい。従って保温材は使用する溶融塩によって決めればよいが、通常αアルミナや安定化ジルコニアの板で電極周辺を取り囲むことによってその目的を達成することができる。これらは保温材としての効果があればよいので多孔質でも良いし緻密質でも良い。炭素などのような導電性のものは電極間を短絡する可能性があること、配置によっては複極的な効果を起こし、電解の効率を低下させることがあるので、なるべく使わない方が良いが、配置、絶縁に注意すれば、使用できることはもちろんである。これらの保温材の取り付けは特には指定されないが、たとえば電極に厚みのある場合は電極側壁にボルト止めすることができる。 In electrolysis of molten metal chloride, chlorine is produced from the anode and metal is produced at the cathode. In the present invention, electrodes for such electrolysis are placed upright, and the periphery of the electrode structure composed of a plurality of electrodes is surrounded except for the upper and lower portions. That is, as a method of arranging the electrodes in an upright manner, a plurality of electrodes are arranged in parallel at a certain inter-electrode distance so that they can be energized. The electrodes are arranged as a so-called bipolar type, and a plurality of electrodes are arranged and electricity is applied from the electrodes at both ends, so that the inner electrode acts as an anode on one side and the other side as a cathode. the as connected in series with the same effect becomes the electrode connection, the cathode each other next to each other in the arrangement of the plurality of electrodes as monopolar, either good an electrode arrangement as an anode. When performing electrolysis in this manner electrodes arranged, outside the electrolytic voltage normally required, but may be hardly considered in the case of the molten salt electrolyte and a so-called electrical resistance of required to electrify in the electrolyte There is an overvoltage of the electrode, and this determines the electrolysis voltage. Of these constituent voltages, heat is removed after removing the voltage required for the electrolytic reaction, so that the electrolysis part is heated to a temperature higher than the surroundings by surrounding the electrode with ceramics as a heat insulating material as in the electrolysis apparatus of the present invention . maintaining, at least in the electrolyte portion can be smoothly viscosity drops generated gas and produce metal discharge of the electrolyte, also occur event called electrolyte liquid flow of the electrolyte portions cause the difference in specific gravity due to a temperature difference in the electrolyte solution becomes active, more Electrolysis proceeds stably. For this purpose, the heat insulating material surrounding the periphery of the electrode is not particularly specified as long as the purpose can be achieved. However, it is considered that the normal electrolysis temperature is 400 ° C. or higher, and that the molten salt is often corrosive, and is insulated. The body is desirable. Thus the thermal insulation material may be determined by the molten salt used, Ru can achieve its purpose by surrounding the electrode near normal a plate of α alumina or stabilized zirconia. Since these may have an effect as a heat insulating material, they may be porous or dense. Conductive materials such as carbon may short-circuit between electrodes, and depending on the arrangement, it may cause a bipolar effect and reduce the efficiency of electrolysis. Of course, it can be used if attention is paid to the arrangement and insulation. Mounting of these heat insulating material is not particularly specified, but for example if a thick the electrode Ru can be bolted to the electrode sidewall.

また複極式の場合電流は小さくなるが電圧が高く、いわゆる漏洩電流が起こりやすい。それを防ぐ為に横部分は此処に示したような保温材で囲ってしまい、更に電極の上下に電流の流れる断面積を規定した型枠を取り付ける必要があるのでその形状が若干複雑になる。そのような場合にはたとえば電極の横部分を電極と同じ厚さの保温材とし、上下を電極間距離だけ出っ張りを作った枠に電極をはめ込み、それを複数個積層して電極体のブロックを作ることができ、全体が保温材として働く。つまり電極体全体を保温材で取り囲むようになるので、より保温効果に優れるという別の効果を生む。 In the case of the bipolar type, the current is small but the voltage is high, and so-called leakage current is likely to occur. In order to prevent this, the lateral portion is surrounded by a heat insulating material as shown here, and further, it is necessary to attach a mold that defines the cross-sectional area through which current flows above and below the electrode, so that the shape becomes slightly complicated. In such a case, for example, the horizontal part of the electrode is made of a heat insulating material having the same thickness as the electrode, and the electrode is inserted into a frame made by protruding the distance between the upper and lower electrodes, and a plurality of them are stacked to form a block of the electrode body. It can be made and the whole works as a heat insulator. In other words, since the entire electrode body is surrounded by the heat insulating material, another effect that the heat insulating effect is more excellent is produced.

この様にして形成した電極構造体は電解質液を充填した槽に浸漬する様にする。勿論此
処でいう電極構造体は電解が行われる電極部分と型枠である額縁または周辺にある保温材を含むものであり、通電体は含まない。電極構造体は電解質液内に完全に埋没する様に設置する。電極構造体を埋没させるのはこの電極構造体中を電解質液が流通し、電解面には常にフレッシュな電解質が接触すると同時に、電解生成物を電極面からスムースに引き離すためであると共に、電解質液の表面温度を電極構造体中の温度よりも低くして電解質の揮散を防ぐ為である。浸漬の深さは特には指定されないが、２０ｍｍから３００ｍｍが望ましく、更に望ましくは５０ｍｍから２５０ｍｍである。つまり電解質液がスムースに動くためには最小限２０ｍｍ程度あることが望ましく、更に電極構造体部によって加温された電解質の熱を除いて電解温度まで低下させるためには電極構造体上方に電解質が５０ｍｍ以上あることが望ましい。なお３００ｍｍ以上では温度効果はよりよくなるが、電解部分への圧力が増加すること、また装置が大きくなりすぎることから経済性の点で望ましいとはいえなくなる。陰極生成物である金属の比重が小さい場合には金属も共に上方にあがってくるが、この場合はこの空間にガイドなどを設けることによって陰極生成物を分離できるようになる。また陽極と陰極の間に多孔性の隔膜をおいて生成物同士での反応を最小限にすることもできる。このように電極構造体を液中（電解質中）に埋没させることによって、電解質液表面では電解槽とほぼ同じ温度まで低下できる。
たとえば塩化亜鉛の電解で電解質液温度を５００℃とした場合、条件によるが実電解温度が５３０℃から５７０℃まで上昇し、電気抵抗が小さくなるし、液粘度が小さくなってガスの抜けが非常に良くなる。またこのようにしても電解液面からミストや塩化物の揮散は、実質的に５００℃でのレベルとなるので、極めて小さくできる。 The electrode structure thus formed is immersed in a tank filled with an electrolyte solution. Of course it had here electrode structure are those containing a heat insulating material on the frame or near an electrode portion and a mold which electrolysis is carried out, does not include the power thereof. The electrode structure is installed so as to be completely buried in the electrolyte solution. The reason why the electrode structure is buried is that the electrolyte solution circulates in the electrode structure, and the electrolytic surface is always in contact with the fresh electrolyte, and at the same time, the electrolytic product is smoothly pulled away from the electrode surface. This is to prevent the volatilization of the electrolyte by making the surface temperature of the electrode lower than the temperature in the electrode structure. The depth of immersion is not particularly specified, but is preferably 20 mm to 300 mm, and more preferably 50 mm to 250 mm . In other words, in order for the electrolyte solution to move smoothly, it is desirable to have a minimum of about 20 mm, and in order to lower the temperature to the electrolysis temperature except for the heat of the electrolyte heated by the electrode structure, the electrolyte is above the electrode structure. It is desirable that it be 50 mm or more. Although the temperature effect is better in the above 300 mm, that the pressure of the electrolyte portion is increased, also have the in terms of economy desirable that the device is too large Enakunaru. Although if the specific gravity of the metal is a cathode product is small metals come together up upwards, this case is so that can separate cathode product by providing a like guide in this space. It is also possible to minimize the reaction between the products by providing a porous diaphragm between the anode and the cathode. Thus, by burying the electrode structure in the liquid (in the electrolyte), the surface of the electrolyte liquid can be lowered to substantially the same temperature as the electrolytic cell.
For example, when a 500 ° C. The electrolyte solution temperature in the electrolysis of zinc chloride, rose to 570 ° C. from the ° C. actual electrolysis temperature is 530 under the condition, to the electrical resistance decreases, leakage of gas I is Do small liquid viscosity Get very good. Further, even in this manner, mist and chloride volatilization from the electrolyte surface is substantially at a level of 500 ° C., and can be made extremely small.

このような電解装置を使用すると、たとえば溶融塩化亜鉛電解において、電解質として純塩化亜鉛を添加物なしで使用し、電解質温度を５００℃程度に保持して電解を行うことによって、電極構造体の周囲は５５０℃以上となるから極めて低い電解電圧で電解でき、しかも塩化亜鉛の蒸気は電解質温度である５００℃時の蒸気圧に相当する僅かな量で電解質表面から出るだけとなり、溶融塩電解で問題となることの多い電解質のミスト及び蒸気による揮散、またそれによって引き起こされる配管の閉塞などを防ぐことができて、これによって電解質の蒸気の処理の手間が殆どかからずしかも蒸気として失われることが少ない安定した電解の継続が可能となる。 The use of such electrolytic apparatus, for example in the molten zinc chloride electrolysis, using pure zinc chloride without additives as an electrolyte, by performing electrolysis to hold the electrolyte temperature to about 500 ° C., the electrode structure ambient can be electrolyzed in an extremely low electrolysis voltage from that Do and 550 ° C. or higher, yet the vapor of zinc chloride will only exit from the electrolyte surface with small amount corresponding to the vapor pressure of 500 ° C. at an electrolyte temperature, the molten salt electrolysis in volatilization by mist and vapors of multi have electrolyte be a problem, also to be able to prevent such clogging of the piping caused by it, thereby losing a little less not yet vapor labor for processing the vapor of the electrolyte Stable electrolysis that is less likely to occur is possible.

此処までに述べたように電極部の周囲を実質的に保温材で覆って、即ち熱放散を防ぐ、あるいは目的以外の液流を阻止する様にし、電解による発熱を電極構造体に保持して極めて低い電解電圧での運転を可能とし、それを電解質液中に液流が起こせるように浸漬してしまい、高い温度での電解により電解電圧が下がり、消費エネルギーを大幅に低下させると共に、電解質液表面温度は実電解温度よりも低く設定でき、それによる蒸気、ミストを大幅に減少できる。以下実施例で説明するが、本発明はこれに限定されないことはいうまでもない。 Covering the periphery of the electrode portion As previously mentioned here substantially heat insulating material, i.e. prevent heat dissipation, or the manner to prevent non-liquid flow purposes, it retains the heat generated by the electrolysis electrodes structure It is possible to operate with extremely low electrolysis voltage, so that it can be immersed in the electrolyte solution so that a liquid flow can occur, and electrolysis at high temperature lowers the electrolysis voltage, greatly reducing energy consumption and electrolyte. The liquid surface temperature can be set lower than the actual electrolysis temperature, thereby significantly reducing vapor and mist. It described below referring to Examples, but the present invention is not a horse have not so limited.

電極１として厚さ２０ｍｍ幅５０ｍｍ高さ１００ｍｍのグラファイト板を用い、その板面（５０ｍｍｘ１００ｍｍ）が互いに対抗する様にその間隔を７ｍｍとして３枚並べ、上下は開口部とし、横を保温材１１として厚さ３ｍｍのアルミナ板で覆った。なおアルミナ板はねじである１０アルミナ製のビスでグラファイト板である炭素板にねじ止めして固定すると共に電極間隔の保持用とした。このようにして炭素を電極１とする電極構造体を作った。炭素の上面には直径１０ｍｍのタップ穴をほり、これに軟鋼製のボルトを取り付け通電体５とした。中央の炭素板を陽極として両端の炭素板を陰極となるようにし、概念図を図２に示した。ここでは電極１が３枚が外に見えているが、実際にはこの表面に保温材１１がかぶっており、電極１の配列は見えない。このようにして作成した電極構造体を図
１に示す外熱式の試験用電解槽２に浸漬した。電解槽２は内径１５０ｍｍ深さ４００ｍｍであり、深さ３００ｍｍのレベルまで純塩化亜鉛を入れた。電極構造体は電解槽２の下端から１００ｍｍに電極構造体の下端がくるように配置した。従って電極構造体の上端から液面までが１００ｍｍとなる。此の電解槽２を使用して電解温度５００℃（電解質液温度）で電解を行った。なお電解で出てくる排ガスは直径２２ｍｍのガラス管（図１中の符号４で示す）を通して、塩素ガスの処理設備につないだが、２時間の連続試験でもガラス管部分へのミストの蓄積は全く見られなかった。電解により得られた電流一電圧の関係を図３中で実線１４に示した。この電流−電圧曲線から得た電解液抵抗は約７Ωｃｍであり、これは約５５０℃の塩化亜鉛の液抵抗に相当した。これから実電解部分は電解浴より約５０℃高くその分電解電圧の低くなること、及び通常５５０℃での電解では塩化亜鉛の蒸気圧が２０ｍｍＨｇ程度あり、通常５５０℃ では多量の塩化亜鉛の揮散が見られるはずであるが、本実施例では塩化亜鉛ガスは電解温度である５００℃に相当するほとんど２ｍｍＨｇ程度の圧力になっているためか、ほとんどガスの揮散が無く安定した電解ができることがわかった。なお電解消費電力は効率を１００％とすると、電流密度４０Ａ／ｄｍ²で１８８８ｋｗｈ／Ｃｌ₂トンであった。 A graphite plate having a thickness of 20 mm, a width of 50 mm, and a height of 100 mm is used as the electrode 1 , and three plates are arranged with an interval of 7 mm so that the plate surfaces (50 mm × 100 mm ) are opposed to each other. 11 was covered with an alumina plate having a thickness of 3 mm. The alumina plate was screwed and fixed to a carbon plate, which was a graphite plate, with a 10 alumina screw, which was a screw, and was used for maintaining an electrode interval. Thus, an electrode structure using carbon as the electrode 1 was produced. A tapped hole having a diameter of 10 mm was drilled on the upper surface of the carbon, and a bolt made of mild steel was attached thereto to form a current-carrying body 5 . The central carbon plate carbon plate at both ends in such a manner that the cathode as an anode, shown in a conceptual diagram of FIG. Here, three electrodes 1 are visible to the outside, but in reality, the surface is covered with a heat insulating material 11 and the arrangement of the electrodes 1 is not visible. The electrode structure created in this way
1 was immersed in an externally heated test electrolytic cell 2 shown in FIG. The electrolytic cell 2 has an inner diameter of 150 mm and a depth of 400 mm, and pure zinc chloride was put to a level of a depth of 300 mm. The electrode structure was arranged so that the lower end of the electrode structure was 100 mm from the lower end of the electrolytic cell 2 . Accordingly to the liquid surface from the upper end of the collector electrode structure is 100 mm. Using this electrolytic cell 2 , electrolysis was performed at an electrolysis temperature of 500 ° C. (electrolyte temperature). The exhaust gas generated by electrolysis is connected to a chlorine gas treatment facility through a glass tube having a diameter of 22 mm ( indicated by reference numeral 4 in FIG. 1), but mist is not accumulated in the glass tube part even in a 2-hour continuous test. I couldn't see it. The relationship between the obtained current - voltage by electrolytic shown in solid line 14 in FIG. 3. The electrolyte resistance obtained from this current-voltage curve is about 7 Ωcm, which corresponds to the solution resistance of zinc chloride at about 550 ° C. Actual electrolysis part now be lower to about 50 ° C. higher correspondingly electrolysis voltage than electrolytic bath, and the electrolysis in the normal 550 ° C. There about 20mmHg vapor pressure of zinc chloride, the volatilization of the normal 550 a large amount of zinc chloride in ° C. but it should be seen that this embodiment the zinc chloride gas probably because that is a pressure of almost about 2mmHg corresponding to 500 ° C. is an electrolytic temperature, Rukoto can hardly electrolysis volatilization of gas has been no stable all right. The electrolytic power consumption was 1888 kwh / Cl ₂ tons at a current density of 40 A / dm ² assuming that the efficiency was 100%.

Comparative example

電極部分の保温材をはずして幅５ｍｍのジルコニア棒によって電極相互を固定した以外実施例１と同じ条件で電解を行った。電解温度も電解質液が５００℃となる様にした。この電解による電流−電圧の関係を図３中で点線１５に示した。実施例１に比較して電圧が高く、これから計算した電解液抵抗は約１０Ωｃｍであり、これから、電解温度電解質液と同じく約５００℃に相当することが分かった。このときの電解消費電力は電流効率を１００％として電流密度４０Ａ／ｄｍ²で２７１０ｋｗｈ／Ｃｌ₂トンであり、実施例１に比較して約４３％消費電力が大きかった。 Electrolysis was carried out under the same conditions as in Example 1 except that the heat insulating material of the electrode part was removed and the electrodes were fixed with a zirconia rod having a width of 5 mm. The electrolysis temperature was set so that the electrolyte solution was 500 ° C. The electrolyte according to current - showing the relationship between the voltage at point line 15 in FIG. 3. The voltage was higher than that of Example 1, and the calculated electrolyte resistance was about 10 Ωcm. From this, it was found that this corresponds to about 500 ° C. like the electrolytic temperature electrolyte solution. The electrolytic power consumption at this time was 2710 kwh / Cl ₂ tons at a current density of 40 A / dm ² with a current efficiency of 100%, which was about 43% higher than in Example 1.

電極の上下に電極と同じ厚さと幅を有する額縁である漏洩電流防止板を電極板の上下に取り付け、それを横側の保温材板にビス止めすることによって固定して電極構造体とした。漏洩電流防止板の高さは５０ｍｍであった。そして実施例１と同じ電解槽にここで作成した電極構造体を電解槽の下端から５０ｍｍが下端となるように設置した。また電極構造体の上端から液面までの高さが５０ｍｍであった。片側の電極を陽極、中間を複極板とし、対面の極を陰極とし、複極型の電解構造体として電解を行った。実施例１と同じようにして電解を行ったところ、電流、電圧の関係は実施例１と同じであり、同様の効果の得られることがわかった。 A leakage current prevention plate, which is a frame having the same thickness and width as the electrode, was attached to the top and bottom of the electrode, and fixed to the side heat insulating plate by screwing to form an electrode structure. The height of the leakage current prevention plate was 50 mm. And the electrode structure created here was installed in the same electrolytic cell as Example 1 so that 50 mm might become a lower end from the lower end of an electrolytic cell . The height from the upper end of the electrode structure to the liquid level was 50 mm. Electrolysis was carried out as a bipolar electrolysis structure with the electrode on one side as the anode, the middle as the bipolar plate, and the opposite electrode as the cathode. When electrolysis was performed in the same manner as in Example 1, it was found that the relationship between current and voltage was the same as in Example 1, and the same effect was obtained.

実施例１と同じ電極配置とし、中央の電極として厚み１ｍｍのニッケルメッシュを外形が炭素電極と同じになるようにたたみ込み、周囲に隔壁として８００℃で焼成したアスベスト繊維織物布を巻き付けた。このアスベスト繊維布を巻いた電極を陰極とし、両端の電極を陽極として実施例１と同様に電解槽に固定した。電解液は塩化マグネシウムに塩化マグネシウム量の２０重量％の塩化カリウムを混合したものとした。この構成を用いて温度６４０℃で電解を行ったところ電解電圧２．３Ｖでの安定な電解ができた。中央の電極部分にはマグネシウム融体の発生が見られ、炭素部分からは塩素ガスの発生が見られた。塩化カリウムを入れており電解温度が塩化マグネシウムの融点以下であるので、塩化マグネシウム蒸気はほとんど見られなかったが、５時間の電解で２２ｍｍの排気用ガラス管の表面にごく薄く白色の沈殿が生じ、塩化マグネシウムのわずかな析出が起こったことがわかる。なお電解温度をマグネシウムの融点ぎりぎりの低い温度にしたにもかかわらずマグネシウムの析出には全く支障がなく、実電解温度はかなり高くなっていることがわかった。 The electrode arrangement was the same as in Example 1, a 1 mm thick nickel mesh was folded as the center electrode so that the outer shape was the same as that of the carbon electrode, and asbestos fiber woven fabric fired at 800 ° C. was wrapped around the periphery. The electrode wound with this asbestos fiber cloth was used as a cathode, and the electrodes at both ends were used as anodes and fixed to an electrolytic cell in the same manner as in Example 1. The electrolyte was a mixture of magnesium chloride and 20% by weight potassium chloride of the amount of magnesium chloride. Could stable electrolysis in electrolysis voltage 2.3V was subjected to electrolysis at a temperature 640 ° C. With this configuration. Magnesium melt was observed in the central electrode part, and chlorine gas was observed in the carbon part. Since potassium chloride was added and the electrolysis temperature was below the melting point of magnesium chloride, almost no magnesium chloride vapor was seen, but a very thin white precipitate formed on the surface of the 22 mm exhaust glass tube after 5 hours of electrolysis. , that see that a slight precipitation of magnesium chloride has occurred. Although the electrolysis temperature was set to a temperature just below the melting point of magnesium, it was found that there was no problem in the precipitation of magnesium and the actual electrolysis temperature was considerably high.

本発明は、いわゆる塩素法による高純度金属の製造に使用し、還元剤として働かせた結果、出てきた金属塩化物を電解により金属と塩素に戻すものであり、たとえばシリコンの製造では生成する塩化亜鉛から塩素と亜鉛金属とを得て、塩素は四塩化珪素の製造プロセスに、また亜鉛は還元剤として使用するクローズドの高純度シリコン製造プロセスに使用できる。また亜鉛をマグネシウムに変えるとチタン金属の精錬にそのまま使用できる。その他比較的少ない量の高純度金属の精錬に使用される塩素法の中で１つのプロセスとして有効に使うことができる。 The present invention is used for the production of high-purity metals by the so-called chlorine method, and as a result of acting as a reducing agent , the metal chloride that has come out is returned to metal and chlorine by electrolysis. obtaining chlorine and zinc metal from a zinc, chlorine four in the production process of silicon tetrachloride, and zinc can be used for high purity silicon manufacturing process closed to be used as a reducing agent. If zinc is changed to magnesium, it can be used as it is for refining titanium metal. Other Ru can be effectively used as a relatively small amount of one process in the chlorine method used refining high-purity metals.

電解装置の概念図である。It is a conceptual diagram of an electrolysis apparatus. 代表的な電極構造体の図面である。1 is a drawing of a representative electrode structure. 電解結果の電流−電圧曲線であり、横軸が電流密度（Ａ／ｄｍ²），縦軸が電解電圧（Ｖ）である。It is the current-voltage curve of an electrolysis result, a horizontal axis is a current density (A / dm < ² >), and a vertical axis | shaft is an electrolysis voltage (V).

１電解電極
２電解槽（電解質液）
３加熱用外熱式炉
４排ガス出口
５電力供給用通電体
６正面図
７側面図
８平面図
９炭素電極
１０保温材取り付けねじ
１１保温材
１２電流密度（Ａ／ｄｍ²）
１３電解電圧（Ｖ） 1 Electrolytic electrode 2 Electrolytic tank (electrolyte solution)
3 Heating External Heating Furnace 4 Exhaust Gas Outlet 5 Power Supply Current Conductor 6 Front View 7 Side View 8 Plan View 9 Carbon Electrode 10 Insulation Screw 11 Insulation Material 12 Current Density (A / dm ² )
13 Electrolytic voltage (V)

Claims

Perform electrolysis in the molten metal chloride in an electrolytic portion between at least one set of an anode and a cathode disposed in the electrolytic cell, the electrolytic apparatus for obtaining melt metal in the cathode with obtaining chlorine gas at the anode, upright to have the collector electrode structure including at least one set of anode and cathode were he location, the upper and lower portions of the electrode structure, it is electrolyte discharge parallel beauty of the chlorine gas and the melt metal is generated An opening is provided so as not to obstruct the supply of the molten metal chloride, and the lateral portion of the electrode structure surrounds the surface so that the arrangement of the at least one set of anode and cathode is not visible, and the temperature of the electrolytic portion. form a part of the electrode structure as a heat insulating material is freely held to a temperature higher than the temperature of the electrolytic cell, the electrode structure is completely immersed in the an electrolyte wherein a molten metal chloride Molten salt characterized in that Solution apparatus.

Molten salt electrolysis apparatus according to claim 1, wherein the conductive mood solutions, characterized by being carried out in diaphragm-free.

The electrostatic mood solutions, with take place with a septum, wherein at least one set of the molten salt electrolysis apparatus according to claim 1, wherein the diaphragm is sandwiched between the positive electrode and the negative electrode.

In at least one set of anode and cathode, a plurality of electrodes are bipolar arranged, a heat insulating material covering the lateral portions of said plurality of electrodes are corrosion der Rutotomoni, leaks to the upper and lower portions of said plurality of electrodes The molten salt electrolysis apparatus according to any one of claims 1 to 3, wherein a frame for preventing current is attached to form a part of the electrode structure that is completely immersed in the electrolyte.

In at least one set of anode and cathode, a plurality of electrodes are arranged monopolar manner, heat insulating material covering the lateral portions fraction of the plurality of electrodes from claim 1, wherein the corrosion resistance der Rukoto 3 The molten salt electrolysis apparatus according to any one of the above .

The thermal insulation material, the molten salt electrolysis apparatus according to claim 1, characterized in that the plate-shaped ceramic 5.

The molten salt electrolysis apparatus according to any one of claims 1 to 6 , wherein an upper end of the at least one pair of anode and cathode is 20 mm or more below the surface of the electrolyte.