Composite electrode of electrolytic method

[Detailed Description of the Invention]

The present invention relates to an electrode suitable for using it by the electrochemistry method, especially the metaled electrolysis extracting method. More particularly, the present invention relates to a useful multiple electrode especially at electrolysis extraction of nickel. Since carrying out an industrial process by the minimum environmental pollution is emphasized increasingly now, the concern about the electrochemical art of extracting metal from an ore is increasing. When one method studied now impresses external current to an electrolysis vessel, it is the electrolysis extracting method of the metal which includes making a cathode electrodeposit metal. An insoluble anode can be used and metal is acquired from the electrolysis solution which contains metal as an anion in a suitable solvent. Electrolysis extraction can be used in order to acquire metal from the solution guided from an ore, a scouring process, or metal scrap skill. The metal of very high purity is acquirable by a suitable electrode, an electrolysis solution, and process conditions giving, and using It isゝThe and this art. On the occasion of metaled electrolysis extraction, one of the big problems is related with development of a satisfactory anode. An anode is a good conductor. It is required to have resistance to chemical erosion in an environment using it. The anode must need to be sufficiently strong so that it be equal to ordinary handling for a commercial use, and it must be effective for the request reaction in an anode, without blocking the activity of a cathode. For example, when using as an insoluble anode by the electrolysis extracting method, the anode must not have a bad influence on the purity of the metallic precipitate of a cathode, and must not block metal precipitation with economical current density. In fact, economical efficiency plays main roles in selection of an electrode. Therefore, the factor which must be taken into consideration is the electric power necessary quantity accompanying the cost of an electrode, its endurance, and its use. In actual commercial operation, the cost of an anode includes not only the cost and the manufacturing cost of material but other expenses or the buying expenses of patent material accompanying a royalty of patent rights or use. The electrode of the present invention is suitable for especially using it as an insoluble anode by electrolysis extraction of nickel. Therefore, the electrode of the present invention is indicated mainly in relation to such a method below. However, the metal of others [ electrode / of the present invention ], for example, copper, zinc, manganese, Electrolysis extraction of cobalt, cadmium, gallium, indium, and those alloys, for example, a nickel cobalt alloy, is attained to, and they are other electrolyzing methods, for example, electrolysis manufacture of chlorine, from salt water, Probably, it will be clear to a person skilled in the art that it can be used also for disassembly of water, negative pole protection (for example, it can set to sea water or underground), and a storage battery electrode. J.R. By Boldt, "The Winning of Nickel", and the nickel electrolysis extracting method using the insoluble anode Described(ed) by PP.362-374 (1967), The electrolysis solution used is a refining leaching solution which are essentially nickel sulfate, sodium sulfate, and solution of boric acid, and an anode is a rolling sheet of a pure lead. A fundamental cathode reaction is :2 (nickel).⁺⁺+2 e->nickel * It comes out. A fundamental anode reaction is :2H.₂O₂->O₂+4H⁺+4e It comes out. It will be accepted that oxygen is emitted with an anode. The lead and the lead alloy are used again as metal other than nickel, for example, copper, and an anode substance for zincky electrolysis extraction. A lead alloy is [ frequent ] more resistant to a certain corrosion environment strongly used by the electrolysis extracting method more mechanically than a pure lead, The operation potential is substantially higher than a precious-metals covering titanium anode, and a lead dissolves, and since it is in the state where it may deposit with a cathode, the possibility of cathode lead pollution always exists in an open circuit. Therefore, a lead is not a completely satisfactory anode substance. In fact, especially, in an oxygen generation environment, only a small number of substance can be effectively used very much as an anode for severe conditions. Black lead is used and the limit is known well again. A remarkable interest is shown in using a platinum group metal covering anode these days instead of the black lead electrode used by electrolysis manufacture of chlorine from salt water. Generally, this kind of anode becomes a valve metal substrate from what gave covering containing at least one sort of platinum group metals, or a platinum metal oxide. Since the tendency which corrosiveness short-circuits by a small tub like a mercury electrolysis vessel was smaller than the element metal in the chloride, the platinum metal oxide called attention. Anode covering which consists of a platinum metal oxide and a base metal oxide especially is encouraged these days. Such covering is characterized in a term like a mix crystal, a solid solution, and a ceramic semiconductor. This kind of anode is used for commercial manufacture of chlorine now. It is those low electric power necessary quantity and the endurance which offset those heavy prices. The example of a patent of many of these fields is as follows. Come out and it is: U.S. Pat. 3491014,3616445,3711385,3732157,3751296,3770613,3775284,3778307,3810770,3840443,3846273,3853739,4003817,4070504 item specification. When these United States patents are scrutinized, some of covering indicated is RuO(s).₂Or RuO₂And IrO₂(And (or) Ir row valve metal oxide, for example, TiO)₂It turns out that it can contain. A platinum group metal does not necessarily show the same characteristic wholly, when using it by an electrolysis vessel. Those actions will change with electrolysis conditions and the occurring reactions. (For example, the oxide, for example, RuO, of a platinum group metal advantageous to the present chlorine manufacture, and a valve metal)₂And TiO₂The anode which has external covering to contain is short-life for the electrolysis extraction use which oxygen generates with an anode. according to [ as for one big problem, an electrode may serve as a passive state, and ] one theory -- this passivation -- oxygen -- exterior covering -- a connoisseur -- it is thought that it is caused by reaching an intermediary conductivity substrate, for example, a valve metal. The electrode which has middle covering between active surface covering and a substrate conductor was proposed. The example of such an electrode can be found out on United States patent 3616302nd, 3775284, and No. 4028215 specifications. Neither of the proposed electrode is completely satisfactory. When the United States patent mentioned above is scrutinized, it turns out that much art is mentioned to manufacture of platinum group metal content covering. In spite of the convenience of covering with electric Metsuki, when it heats in the air, emphasis is placed on "paint" application of the platinum group metal compound which reacts with oxygen and forms an oxide. For example, RuCl₃It is RuO when it heats by abbreviation 200~about 700-degreeC in Is air.₂It is alike and is changed. This result is L.D.Burke et al, "The Oxygen Electrode", and J.C.S.Faraday I. vol.73 (11) It was produced from 1669-1849 (1977), and is RuO in this literature.₂A covering electrode is usually RuCl.₃Being built by heating application titanium in the air for several hours is pointed out. RuO according to the thermal oxidation of electrolytic deposition ruthenium in this literature₂It is recorded that discovery that research of manufacture possibility and electrolytic deposition electrode covering of an electrode are dissatisfied from oxygen potential and a point of corrosion, and the above-mentioned corrosion are proved when yellow appears in solution. (The volatile tetroxide, i.e., RuO, of yellow [ output / which may exist in an acidic solution from a Poulvixks (Pourbaix) figure as a result of the dissolution of ruthenium ])₄It comes out and a certain thing has been reported to other places. It was newly found out that it is a very effective oxygen electrode where the Ivy electrode attached using electrodeposited ruthenium- iridium middle covering which has oxidized at least one copy and has an unelectrodeposited ruthenium dioxide layer on the surface has low oxygen potential and which is durable in an acid environment. Especially the object of the present invention is to provide the electrode material which can be used as an insoluble anode by the electrolyzing method for electrolysis extraction of metal like nickel, copper, and zinc. Other objects of the present invention are to provide the electrode material which has a long life and low electric power necessary quantity, when it is used as an anode of an electrolysis vessel. Other objects of the present invention are to provide the electrode material which has corrosion resistance, when it is used as an anode at operating current density and temperature in a water acid environment. Other objects of the present invention are to provide the effective electrode as an insoluble anode for electrolysis extraction of nickel. Probably, these of the present invention and other objects will be clear to a person skilled in the art from the following explanation and an example. According to the present invention, when oxygen occurred with an anode and high acid concentration and high temperature were used, the effective multiple electrode was especially found out as metal, especially an insoluble anode for electrolysis extraction of nickel. Generally, in order to use the electrode of the present invention by an electrolysis vessel, it is an effective multiple electrode as an insoluble anode by the metaled electrolysis extracting method especially, and this electrode consists of multilayer covering provided in at least one copy of a conductive substrate and its surface, and it is the above-mentioned covering, It is a direct barrier layer on a substrate, b -- the unelectrolyzed Metsuki external layer which essentially consists of ruthenium dioxides and to carry out -- and c ruthenium and the electric Metsuki metallic precipitate of iridium -- Then -- the middle class between the above-mentioned barrier layer which includes the precipitation thing which oxidized partially even if small, and the above-mentioned external layer. Iridium serves to control the dissolution of ruthenium, when using a multiple electrode as an anode under oxygen generating conditions. Therefore, although iridium is little at least, it needs to exist in a quantity effective in reducing that ruthenium dissolves in an electrolysis solution during use. According to one field of the present invention, an electrode is used as an insoluble anode by the electrolysis vessel for carrying out electrolysis extraction of the metal from the solution containing metal. In a desirable embodiment, the present invention is used as an anode by the electrolysis extracting method of nickel. The barrier layer of quantity effective in according to other fields of the present invention, a multiple electrode holding the current delivery capacity of an electrode on a valve metal substrate, although it is little, The first layer that is flash covering of the a maximum of about 0.5-micrometer thickness of a platinum group metal typically, At least about 0.1 micrometer in thickness The third layer that is the second layer and the ruthenium oxide content external layer which contains an effective amount of ruthenium dioxides to low oxygen potential although it is little at least which are middle electrodeposition ruthenium- iridium layers (a maximum of about 4 micrometers or 5 micrometers) typically is deposited continuously separately, Under the present circumstances, before depositing external covering, it is prepared by the method of including giving the substrate which has the middle class who consists of a barrier layer and a ruthenium- iridium electrodeposition thing to the temperature raised in an oxidative atmosphere, and oxidizing the surface of a ruthenium- iridium electrodeposition thing partially at least. A ruthenium- iridium electrodeposition thing can also be called an alloy. An alloy means the mixture of the very detailed particles of ruthenium which has metal appearance at least, and iridium. These particles are mix crystals, or can be in a solid solution state, and the microscope characteristic of an electrodeposited coat is difficult to determine, since the coat is very thin. The main features of the electrode of the present invention are in a specific combination of composition of the layer of multilayer covering, and the self-possessed method of a layer. Covering mentioned above is on a conductive substrate. The substrate which must be conductivity needs to be a resistant substance by the environment where it is used. The substrate can be a valve metal or black lead. The term a "valve metal" is used in the ordinary meaning in the case of being applied to electrode material. A valve metal is a high-melting corrosion-resistant conductivity metal which becomes a passive state, namely, forms a protection coat in a certain electrolysis solution. The examples of a valve metal are titanium, tantalum, niobium, zirconium, hafnium, molybdenum, tungsten, aluminum, and those alloys. Titanium is a substrate substance desirable for relative cost to other substances which are electric and have chemical property, availability, and the characteristic that may be compared. the shape of a substrate -- the present invention -- an intermediary -- it is not important. It is many shape and sizes and using an electrode, for example as a sheet, a net, X pan Doume Tal, a pipe, a stick, etc. is known well. Titanium can be a sheath on a for example more conductive metal, for example, copper, iron, aluminum, or those combination metal. A valve metal substrate receives processing, in order [ in order to clean the surface before applying covering preferably ] to make it coarse. As pure, removal of oil and fats and dirt and what kind of oxide coat thing removal which may be generated on a valve metal are mentioned. In order to rough-Rack the surface of a valve metal, the usual art, such as etching or grit blasting, can be used, for example. Especially suitable art is grit Plasting which uses silica sand. The barrier layer which deposits on a substrate improves the endurance of an electrode. It is considered to work as an oxygen diffusion barrier over a substrate, and (or) to carry out an action as a current conveyance layer, and (or) to work as suitable supporters. Suitable supporters mean that it improves the quality and adhesion nature of an electrodeposited layer. Anyway, the main functions of a barrier layer are holding the current delivery capacity of an electrode under existence of the emitted oxygen. As for a barrier layer packet product, it is advantageous to choose out of the group which consists of a platinum group metal, gold, those alloys, a mixture, an intermetallic compound, and an oxide. It can be one silicification thing, the nitriding thing, and carbide of an ingredient of a substrate substance. As for a barrier layer, it is preferred to contain at least one sort of palladium of a platinum group metal, platinum, iridium, and rhodium. Probably palladium and iridium are O without completely carrying out a special process.₂Since it is effective in holding the current delivery capacity of an electrode as a barrier over transportation, it is desirable. It is dark HNO although platinum is effective.₃Or 0.1NKMnO₄of -- additional processing is needed by being immersed in an oxidization medium [ like ]. It was found out that the silicification thing, the nitriding thing, and carbide of at least one ingredient of a valve metal substrate are also suitable as a barrier layer. Standard art can be used for depositing such covering to a substrate. These covering has Udah of thickness larger than a platinum group metal barrier layer. For example, the nitriding thing covering can be about 2 micro in thickness, and the silicification layer can be about 250 micro in thickness. In a desirable embodiment, an electrode contains palladium or the iridium content layer which adjoined the valve metal. The palladium layer which works as a barrier layer on a substrate promotes the adhesion nature to the substrate of a ruthenium- iridium electrodeposition layer again. Palladium or iridium can be deposited by chemical or thermal decomposition, electric Metsuki, electrophoresis, etc. from solution depositing on arbitrary methods, for example, a substrate, or slurry. It is convenient, cheap, and is quick, and the labor of time is not severe as compared with thermal decomposition, either, and since electric Metsuki is easily controlled as compared with electrophoresis, chemical deposition, or vapor deposition, it is preferred. The palladium layer is at least about 0.05 micrometer in thickness. The optimal thickness is about 0.2 micrometer. Generally, asking is sufficient metal to cover a substrate completely substantially. For example, 0.25mg/cm²It was found out that they are enough deposits to have carried out the sandblast of the of palladium deposition thing, or cover completely the substrate surface made coarse by other methods. Metsuki is difficult for iridium and is more expensive than palladium. However, flash covering of iridium works as an effective barrier. :bath whose example of a publicly known palladium electricity plating bath is as follows and which exists Pd(PdCl₂- H₂As O 5~50g / NH₄Cl 20~50g/ HCl Quantity PH which maintains PH 0.1-0.5 Temperature 35-50"C current density Five to 10 mA/cm²Yoku Pd(Pd(NH₃)₂Cl₂It carries out. 8~16g / NH₄Cl 60~200g/ PH 8 -9.5 temperature 25-35"C current density 10mA/cm²To an iridium barrier layer, Yoku of a statement can be used for a U.S. Pat. No. 3693219 specification. The middle class between flash covering of palladium and outside ruthenium dioxide covering becomes essential from ruthenium which deposited with electric Metsuki art, and iridium. Although the precipitation thing can form ruthenium- iridium with much art, It is advantageous especially to carry out electric Metsuki of the covering in that can deposit the metallic coating of suitable thickness by one operation, and can form the layer of uniform composition and it can form a precipitation thing chemically quickly by the way neither time nor a labor is severe as compared with thermal decomposition art. According to the present invention, a ruthenium- iridium layer deposits in the state of metal with electric Metsuki art. Although Co-deposition(ing) is preferred as for a layer, it can deposit a layer separately, for example using a ruthenium plating bath given in a U.S. Pat. No. 3576724 specification, and an iridium plating bath given in a U.S. Pat. No. 3693219 specification, and, subsequently can carry out thermal diffusion of them. Although the present invention is not limited to any specific electroplating methods to manufacture of a layer, especially the suitable layer forming method and Yoku can find out on the U.S. patent application No. 924632 specifications (it quotes in the text as reference dated July 14, 1978). As mentioned above, in itself [ electric Metsuki ruthenium ], an anode corrodes quickly in oxygen generating potential, and it enters into acid solution in the 8 value state in about 1.1v (opposite S C E) excess potential. It is expensive in respect of the loss of the expensive precious metals, and this is RuO.₄Since there is possibility of evaporation, it is dangerous. When iridium was added to electrodeposited covering, it was found out that the dissolution of ruthenium is controlled. An effective iridium addition level is dependent on the conditions for which an anode is used. Control of the ruthenium dissolution has a remarkable effect by very little iridium addition. For example, it is 500mA/cm in sulfuric acid.²In the life test accelerated with Of current density and ambient air temperature, iridium addition increased the anode life from 1 hour (with no iridium addition) about 1% of the weight also in at least 11 hours and 95 hours, and iridium further increased the anode life 2% of the weight in a similar manner. Iridium addition is 36% of abbreviation 1~abbreviation typically. It is 30~50mA/cm about nickel.²When carrying out electrolysis extraction at the current density of a grade, and the temperature of about 55~80 degreeC, it is effective by very little iridium addition. A maximum of about 50mA/cm²In the advantageous embodiment of the present invention for using it by Of current density, the iridium level of an electrodeposited layer is abbreviation, preferably an excess of about 1%, for example, about 2%, and 4% at least. For example, unelectrolyzed Metsuki RuO₂In such an anode that has one outer layer which will be accepted, the dissolution which ruthenium can observe with about 4% of the weight of the iridium level does not exist. About 50mA/cm²As for an iridium level, when using it to extra current density, it is preferred that it is at least 2%. RuO₂Without an outer layer, in order to prevent the ruthenium dissolution, a 4% excess amount, for example, 7% of iridium, is required. The metal electrodeposition layer must be given to oxidation treatment, and a higher iridium level, for example, 7%, must oxidize the surface partially at least. When using severer electrolysis conditions, a lot of iridium for controlling the ruthenium dissolution is required, and obtains. If even the case of the anode whose iridium content is not sufficiently so high as the ruthenium dissolution takes place first is used in anode, oxide covering will generate, eventually covering will be protected and the further dissolution of ruthenium will be prevented. However, the initial dissolution is avoided and it is RuO.₄In order to avoid the danger of generation, ruthenium dioxide content covering generated by non-electrolytic treatment is provided on the surface of an electrode. However, before depositing an additional layer on electric Metsuki ruthenium- iridium covering, a ruthenium- iridium alloy layer is processed in the air, and the surface oxidizes partially at least. This means that the surface can partially or essentially oxidize completely, or the layer can partially or essentially oxidize completely to the arbitrary depth of a layer. The middle class's surface oxidization can be performed at the temperature of abbreviation 400~about 900-degreeC to a deposit in the atmosphere which is an oxidizing quality. Air is preferred. a desirable embodiment -- the middle class's heat treatment -- about -- 400~about 700degreeC, for example, about 593 degreeC, -- about -- 5~about 60 minutes -- for example, it is carried out for about 15 minutes. Advantageously, a ruthenium- iridium layer has the abbreviation 0.1~abbreviation of 4 micrometers, or a thickness of 5 micrometers, and has preferably the 0.5~abbreviation of 2 micrometers, for example, a thickness of about 1 micrometer. If it carries out as surface oxidization gives a color change observable purple from metallicity, it is enough. This is the proof of surface oxidization. When such oxidation treatment is given, it is known that the oxide of at least versatility [ surface ] of ruthenium and iridium will be generated. The ruthenium- iridium electrodeposition layer considered to be an alloy oxidizes clearly in the surface at least. The existing main phases are RuO(s).₂It comes out, and it is and this thing can form other oxides and solid solutions which are generated on the surface. The electrode containing the iridium of an adequate amount can be designed in view of the dependence over an operating condition. It is made to agree with an electrode life and, as for the field of cost to an iridium level, it is preferred to make it as low as possible. The surface coat of the desirable anode of the present invention contains the ruthenium dioxide generated from the source of non-electrolyzing-like self-possessed as an essential ingredient. This is for abolishing the ruthenium loss in the case of using it in anode even in the first stage, as mentioned above. The ruthenium dioxide will optimize the validity of material as an oxygen electrode, if having low oxygen overpotential is known and it exists in the surface as an additional layer. For this reason, it will become possible to use an electrode for making initial dissolution possibility of ruthenium into the minimum with sufficiently low potential, if it pulls. It is TiO because of other the ingredient which is not active in electrolysis, for example, adhesion nature.₂,Ta₂O₅of -- the oxide of a substrate ingredient [ like ] can be existed. At the desirable embodiment of the present invention, an external layer is RuO at least about 80%.₂It contains. the embodiment in which an un-active ingredient exists -- an external layer -- about 80~ -- about 99% of ruthenium dioxide, and about 1~ -- about 20% of un-active ingredient, for example, a titanium dioxide, is contained. A suitable outer layer is 80%RuO.₂-20%TiO₂,85%RuO₂-15%TiO₂,90%RuO₂-10%TiO₂,80%RuO₂-10%TiO₂-10%Ta₂O₅It can contain. However, the requirements to an un-active ingredient like a valve metal oxide are not so important, and removing is even possible in the electrode of the present invention. This is external RuO (non-electrolyzing target).₂The requirements for thickness of a deposit are because it is not criticality-like as the case of the usual electrode altogether built with a painted type deposit in the electrode of the present invention. It needs to form the thickness reported for the usual painted type electrode to be covering of no less than eight layers by continuation deposition, and a calcination process is intermittently carried out during the generation. With the electrode of the present invention, it is RuO.₂(Non-electrolyzing deposition) Since a layer is thinner like covering below 1 or two-layer, the necessity for an additional binding material is reduced. In fact, RuO generated from paint without including an additional oxide component as an outside surface coat and a Ru-Ir layer₂Use -- the endurance is there anode was built by things. When using resin acid salt, a certain oxide can be guided from the usual commercial combination thing, but such a paint combination thing can be applied, without adding an additional oxide. In order to form a ruthenium dioxide content external layer, the arbitrary art in which it does not electrolyze can be used. For example, many methods of forming ruthenium dioxide covering from the water containing a part for ruthenium or organic Vehicle are known. For example, the ruthenium can exist as a compound like the halide which oxidizes to a ruthenium dioxide, or resin acid salt, if heat treatment is received in an oxidative atmosphere. It is indicated to the patent which some methods of forming ruthenium dioxide surface covering from unelectrolyzed Metsuki covering mentioned above. In one method, ruthenium chloride solution is applied as paint and ruthenium dioxide covering is formed by the desalination matter of ruthenium chloride, and oxidization. For example, RuCl₃·3H₂It is more applicable to the complex which covered beforehand the solution which dissolved O in the suitable carrier, and processed it immersed in brush coating, a spray, or A tiger. 1 cm of electrode surface products²A sufficient number to give the ruthenium content of at least about 0.1 mg of hits of covering is applied. Covering can be calcinated separately, or can dry each covering and can calcinate the last covering. calcination -- for example, the inside of the air -- about -- 315~about 455degreeC, for example, about, -- 315~about 455-degreeC -- about -- it is carried out for 15~about 60 minutes. It can carry out Both self-possessed [ of titanium or other un-active ingredients ] with ruthenium using the usual art. Typically, it is RuO.₂The self-possessed quantity (namely, before accumulation in use) of the beginning of a content outer layer is at least about 0.1mg/cm.²It comes out. The thickness of initial self-possessed quantity is 1mg/cm of abbreviation 0.3~abbreviation.²It comes out and it is preferred that it is. It is usually RuO during use at an electrolysis vessel.₂Since Accumulation happens, it is RuO.₂Early in thickness is RuO.₂of -- it is for keeping the middle class's precious metals from dissolving, and securing low oxygen overpotential by an electrolysis vessel, before suitable accumulation takes place. Thus, a precious-metals loss is made into the minimum. As mentioned above, in the desirable embodiment of the present invention, a multiple electrode is used as an insoluble anode for nickel electrolysis extraction. Although not limited to any methods, in order to maintain about 40~100g / nickel, 50~100g / sodium sulfate, and PH in sulfuric acid about 0~5.5, the nickel electrolysis extracting method which uses the electrolysis solution containing a maximum of 40g / boric acid is known. In the one electrolysis extracting method, an anode is put in by the bag, anode liquid is a sulfate solution containing about 40~70g / nickel (as nickel sulfate), 40g / sulfuric acid, 100g / sodium sulfate, and 40g / boric acid, and PH of anode liquid is about 0. Electrolysis extraction is the temperature of about 50~70 degreeC, and about 30~50mA/cm.²It is advantageous to carry out with of anode current density. The following example gives a person skilled in the art a better understanding of the present invention. In all the tests, anode potential is the bolt measured to the standard Callot Mel electrode (S C E), and H/T is a cable address which shows the adjustment, i.e., the temperature, time, and atmosphere of a layer of a complex sample. For example, the self-possessed quantity in various layers of the precious metals or its oxide, and an alloy is given as a nominal value. Example This example explains the activity of the above-mentioned electrode when a barrier layer uses as an anode manufacture of the typical electrode of the present invention which is palladium, and for electrolysis extraction of nickel. Based on a titanium base material substance, some multilayer samples are manufactured as follows. The titanium sheet which made the surface coarse is cleaned and thin covering of the precious metals is Metsuki(ed) as a barrier layer. In order to make titanium coarse and to clean it, it is SiO about titanium.₂A sandblast is carried out with sand, a brush is carried out with a pumice stone, and they are ToゝCan and 0.5MNa.₂CO₃It cleans in negative pole in inside, and, subsequently dries remains pumice stone particles by ToゝThere except for dirt. Then, the thin palladium deposition thing of 0.6 micrometer of abbreviation 0.1~abbreviation is Metsuki(ed) using a publicly known electric plating bath to the cleaned substrate. In a certain sample, a palladium deposition thing is covered over a special process. For example, it is 5%H about palladium coating titanium of a certain sample.₂- The remaining N₂It processes by 593 degreeC in Atmosphere for 1 hour. It was found out among the research process of material that such processing of a palladium layer is removable without a harmful effect remarkable in an electrode life or performance. For example, the ruthenium- iridium middle class of about 1/2 ~ about 4 micrometer thickness is Metsuki(ed) in a palladium layer from a sulfamic acid salt bath, and the precipitation thing which contains iridium and remainder ruthenium about 4% is given. It is maintained by PH0.9 and temperature C of 57 degrees, and Yoku currently indicated by the U.S. patent application mentioned above is 20mA/cm.²It is operated by Of current density. A ruthenium- iridium precipitation thing is processed for about 10~20 minutes by about 500~600 degreeC in the air, and oxidizes the surface. Surface RuO₂About a layer, it is RuCl to a complex.₃·3H₂It applies to each sample by covering n-butanol solution of O twice. After each application and an electrode are dried under a heat lamp (about 65 to 93 "C), and it is about 1mg/cm.²Of ruthenium chloride self-possessed quantity is given, subsequently a complex is heat-treated by abbreviation 450~about 600-degreeC in the air, and a chloride is changed into the dioxide of ruthenium. If uniform covering of dark blue is obtained and this covering is rubbed with a finger, it will adhere, but when it applies to a tape test, it does not adhere completely. A tape test includes making the strip of a tape adhere to covering firmly, and exfoliating a tape quickly. Next, covering is seen whether the tape torn off from the Tonight base. Under the conditions which imitated the anode liquid in the case of the anode nickel electrolysis extraction containing a bag (i.e., the water electrolysis solution which consists of 70g / nickel (as nickel sulfate), 40g / sulfuric acid, 100g / sodium sulfate, and 10g / boric acid), a sample is tested as an anode. The bath is temperature 70degreeC, PH0~0.5, and current density of 30mA/cm²It is alike and maintains. A test will be arbitrarily stopped, if anode potential amounts to 2 v (opposite S C E). The life of a typical sample is shown in a table with change of manufacture of the pointed-out sample. The anode of the present invention is effective in electrolysis extraction of nickel, and the data of a table is 30mA/cm.²Of current density shows that the anode operates with the potential where about 1.19~1.4 v / near S C E were stabilized very much. Example This example explains to external covering and the middle class of the complex anode of the present invention the effect which various processing conditions do. The effect to A external layer RuCl₃·3H₂The complex sample which does not have a barrier layer by the same method as an example except for changing the last heat treatment in the air of O deposit about time and temperature is prepared. It is 1NH about a sample.₂SO₄It is neglected at the temperature of a maximum of 70 degreeC to inside. Table-A is RuO.₂The effect which heat treatment change of a layer exerts on an anode is shown.

[Table]

Table - A Processing Temperature °C Time, part Effect Result 260 15-60 Melting Solution 315 30 A low Law 370 30 A low Law 425 15-60 A low Law 455 30 A low Law The temperature-time cycle in which the above-mentioned result does not change a ruthenium chloride deposit into an oxide shows that covering dissolves shortly after contacting acid. Covering adhesion nature is improved with higher heat treatment temperature, i.e., 455 degreeC, and it is proved that the adhesion nature is better than the case of 315degreeC or 370 degreeC. The optimal time of heat treatment is measured by a tape test, and is about 30 to 60 minutes. The effect which B temperature-time exerts on the middle class A sandblast is carried out, and it rubs with a pumice stone, and prepares a sample by Metsuki(ing) a Ru-4%Ir alloy deposit to the titanium base material cleaned in negative pole. A ruthenium- iridium layer is applied to various temperature-time cycles in the air. Then, a complex is used as an electrolysis solution and it is 1NH.₂SO₄They are ambient air temperature and 5000 A/m as an anode in inside.²It tests with of anode current density. Table-B shows the effect which a heat treatment condition exerts on an anode.

[Table]

The result of a table shows that the desirable temperature-time cycle to heat treatment of an alloy is 593 degreeC15~30 minutes. In a disadvantage crack and a substrate, the one nature of Coprecipitate oxidizes unfairly in 704 degreeC 1 hour. An insufficient oxide generates in 426 degreeC 1 hour. The effect which C atmosphere exerts on an alloy layer A sample is prepared by the same method as the sample prepared in portion B of this example except for changing the heat treatment atmosphere of 4 % of the weight of ruthenium- iridium alloy layer. A complex is substantially used for an example as an anode by imitation nickel electrolysis Collection bath of a statement except for maintaining Yoku to 55 degreeC. Table-C is essentially pure O about an alloy layer.₂The result compared with the electrode which processed in the air the electrode prepared by heat-treating in Atmosphere is shown.

[Table]

Example This example explains the effect which adds titanium to a ruthenium oxide outer layer. It is based on the weight of titanium and is RuCl about 15% of the weight of a titanium chloride.₃·3H₂It adds in O solution and prepares a complex by the same method as an example except for making ruthenium covering solution with methanol instead of butanol. The ruthenium chloride solution used in order to deposit an external layer is RuCl.₃·3H₂O and TiCl₃It prepares by dissolving (20%) of solution in methanol so that a ruthenium pair titanium weight ratio may be set to 85:15. H₂O₂It adds, and it oxidizes and changes titanium into the second titanium (+4) state. Self-possessed quantity is an average of 1.2mg/cm to the ruthenium- iridium alloy layer which oxidized ruthenium- and titanium content solution to generate.²It applies by performing covering several times until it comes to be alike. Covering which dries each covering under a heat lamp (65-93"C), and continues after that is applied. An electrode is heated by 454 degreeC in the air after the last covering for 30 minutes. Generation material has a dark blue external layer which has good adhesion nature, and shows only slight covering exfoliation by a tape test. Test data is shown in a table. When it tests by an imitation nickel electrolysis extraction tub, this kind of anode is TiCl.₃RuCl which is not contained₃·3H₂Initial anode potential substantially equal to what is shown by covering which has the surface coat generated from O paint is shown. The life of a table is TiO of a table.₂It is shorter than the life of the electrode as for which Include is not and which may be compared. Probably, covering art must be improved. Example This example explains the effect of the palladium barrier layer by the present invention, and the ruthenium- iridium middle class as an oxygen electrode by various tests. Although it could be coarsely exhausted, the layer was deposited essentially like the example to the titanium carried out for being and the complex sample was prepared, the sample was prepared as what has a ruthenium- iridium layer and it does not have, and it had palladium and did not have. One sample was prepared so that it might have the electrodeposited ruthenium middle class. Composition change, processing of a layer, and a test method are shown.

[Table]

A section By the test shown in table-A, samples 7 and 8 are 5%H.₂/N₂It has the 0.1-micrometer-thick thin electric Metsuki palladium deposition thing heat-treated by 593 degreeC in inside for 1 hour. RuO which formed samples 6, 7, and 8 from the 3 ruthenium-chloride content paint deposit heat-treated by 454 degreeC in the air for 30 minutes₂It has The surface covering. RuO₂Self-possessed quantity is 0.5mg/cm.³It comes out. Sample 8 is RuO of a palladium layer and electrodeposited ruthenium- 4% iridium.₂It has the middle class between layers. Exterior RuO₂Before applying a layer, a 0.5-micrometer-thick ruthenium- iridium layer is heated by 593 degreeC for 15 minutes. Samples 6, 7, and 8 are used as an anode with imitation nickel electrolysis extraction anode liquid which was indicated for the example. The data in which time to oxygen generating versus anode potential is shown is shown in table-A.

[Table]

The data of table-A is RuO to :Ti which shows the following.₂Although the electrode (sample 6) which becomes essential operates with good potential from what was covered, it is short-life as an oxygen electrode. The electrode (samples 7 and 8) which has Pd-barrier layer is RuO of Example 6.₂It has the operation potential which may be compared with operation potential. the life of the sample to which the Ru-Ir middle class increases the life of an oxygen electrode (8 pairs of sample sample 7), the potential in the case of sample 8 is stabilized, it is low for about 4000 hours, and this does not have a Ru-Ir layer -- almost -- 4 times -- it is . In a certain within the limits, it is RuO under surface covering (namely, operation layer).₂Increase of self-possessed quantity will understand that the life of an electrode decreases. RuO with request thickness suitable for the range of the thickness of covering₂The art and the cost side which apply covering will rule over greatly. B section By a test given in table-B, samples 9 are Pd barrier layer, the electrodeposited Ru-4%Ir middle class, and RuO by the present invention.₂A surface coat is provided and prepared. In sample 10, the middle class is electric Metsuki Ru. Although samples 9 and 10 are tested for an example with the essentially same imitation nickel electrolysis extraction anode liquid as the thing of a statement, it is operated by 55 degreeC.

[Table]

The data of table-B shows that the life of an anode increases remarkably, when iridium is added to the middle class. C section (Sample 12 according sample 11 which does not have a barrier layer by the test shown in table-C to the present invention, and severe conditions, i.e., 1NH)₂SO₄It is 5000 A/m in an electrolysis solution.²It comes out and compares as an oxygen electrode.

[Table]

The data of table-C shows that a palladium barrier layer increases the endurance of an anode. Example This example explains change of a barrier layer. Electric Metsuki of the various metal is carried out at the titanium sheet which was made coarse and cleaned, and a complex sample is prepared by subsequently Metsuki(ing) Ru-4% Ir of electric metal skin. The data in which the result of the test using such a complex as an anode is shown with the imitation nickel electrolysis extraction electrolysis solution substantially indicated for the example is shown in a table. The processing which the various thickness of a deposit and deposits received is shown (if it is).

[Table]

[Table]

Ir and Pd are suitable for especially the above-mentioned data as a barrier layer, and it is shown that oxygen processing improves the validity of a platinum barrier layer. Having processed Pd layer of sample 1 in a reduction atmosphere is admitted, and as mentioned above, this processing is not necessity for effective Pd barrier layer. However, platinum needs processing in an oxidization medium, in order to be effective. It is preferred to perform such platinum processing at room temperature. Example This example shows the effect of change of the thickness of Ru-Ir and Pd layer. Change of A section-Ru-Ir thickness It is Pd/Ru-Ir/RuO on three layers of compound sample by the present invention, i.e., Ti.₂The thickness of a Ru-Ir layer is changed and prepared by the substantially same method as what indicated the covered sample for the example. In the prepared sample, they are Pd and RuO.₂Is fixed -- namely Pd = 0.1-micrometer and H/T=593-degree C-1-hour-5%H₂/N₂Or a processing pear RuO₂=0.5mg/cm²30 minutes in the H/T454"C-air The data of a table shows the time to 2V, when it tests with imitation nickel electrolysis extraction anode liquid using the conditions of a statement for an example.

[Table]

The data of a table operates effectively, even if the electrode of the present invention changes in the range whose thickness of Ru-4%Ir covering is 0.5 to 4 micrometer, and it is shown that the optimal thickness is the range of about one to 3 micrometer. Change of B section-Pd thickness In palladium, it is 1 micrometer of abbreviation 0.05~abbreviation/cm, i.e., a maximum of about 1.3mg, about the thickness of Pd deposit to the titanium sheet which was made coarse and cleaned.²A sample is prepared by changing and carrying out electric Metsuki in the range of Pd. It is 1NH about a sample.₂SO₄It tests as an oxygen electrode at room temperature in inside. 2mA/cm²of -- the case where it is made to operate with fixed current density -- the graph as a function of Pd self-possessed quantity of the potential of an electrode -- 0.2mg/cm²Extra Pd level shows carrying out the action of the surface like pure Pd, and this points out that a titanium surface is completely covered with palladium. About 0.2mg/cm²At the following palladium, Pd self-possessed quantity of titanium base material is about 0.2mg/cm.²Potential is affected so that it may be proved by potential rise, as it decreases below. Example This example is an effect of iridium, an effect of the middle class's oxidation treatment, and RuO of the present invention in the test as an oxidization electrode.₂Contribution of a layer is explained. The complex sample which has all the electric Metsuki ruthenium content layers that changed the iridium content 0 to a maximum of about 12% is prepared. An electric metal skin is directly deposited on the titanium which was made coarse and cleaned. Each sample is about 1mg/cm.²It has a self-possessed quantity of an electrodeposited thing. Then, except for samples 24 and 25, each sample is processed for 15 minutes by 593 degreeC in the air. External layer RuO of the addition which generated samples 18, 20, and 24 from ruthenium chloride content paint respectively₂(0.8mg/cm²It has and this external layer is heat-treated for 30 minutes by 450 degreeC in the air. Sample 25 may compare with sample 21 except for not receiving oxidation treatment. 1NH by which these samples are operated with the current density which increases until the color change of an electrolysis solution is observed₂SO₄It is used as an anode with an electrolysis solution. The white Teflon (Teflon is trademark of E. I. du Pont de Nemours) tape inserted in the stopper to each test is extracted, and it is To understand. It is H about the outflow gas from a test container.₂SO₃:H₂It is made to whip through the solution of O ratio 1:5. H₂SO₃A change remarkable in inside does not take place. An observation matter is shown in a table. The result of a table shows the next: 1 Existence of Ir controls the corrosion of Ru. When an iridium content increases to ~ [ 3.9% of ] 0 to 9.4%, the current density which coloring of an electrolysis solution begins is 30mA/cm.²Or et al. [ 250mA/cm ]²It is alike, increases and is RuO on a tape.₂·2H₂O deposits decrease in number in a very small quantity from black quantity (samples 17 and 19, 22 references). 2 RuO Generated on Surface from UnElectrolyzed Metsuki Deposit₂The presence of is RuO in all cases.₂·2H₂O(RuO₄pass generation -- it is -- the generation of a ruthenium content deposit and the corrosion of Ru which are considered are controlled. It is RuO if Ir does not exist.₂When a surface coat exists, the deposit on a tape is less than the case where the layer does not exist (see the samples 17 and 18), and corrosion starts with higher current density. With the Ru-Ir deposit which is not heat-treated, it is RuO.₂When exist(ing), there are few ruthenium content deposits on a tape, and there are also few amounts of corrosion of Ru (sample 25 and 24 references). A Ru-Ir deposit is heat-treated and it is RuO.₂When exist(ing), it is a maximum of about 250mA/cm.²A ruthenium content deposit is not found out in Of current density (refer to sample 20). 3 Furthermore, the above-mentioned result shows that a Ru-Ir layer needs to be oxidized in the form of a protection oxidization coat. When not heat-treating Ru-Ir, the corrosion of Ru is 30mA/cm.²It starts coming out and a dark-brown deposit exists on a tape. When Ru-Ir was heat-treated, corrosion started with every and high current density, and volatile matter content was reduced to a very small quantity (sample 21 and 25 references). The above-mentioned result shows that the optimum amount of the iridium in Ru-Ir can be beforehand determined based on corrosion and economical efficiency as opposed to some operation conditions. For example, iridium is contained about 3.9% and it is RuO.₂Sample 20 which has external covering is a maximum of 250mA/cm.²It can be used, without producing the great dissolution of ruthenium in an electrolysis solution in Of current density. 30-50mA/cm²It is RuO about less than 4% of iridium to lower-level current density.₂It can both be used, for example, data shows 1% or 2% being enough, and obtaining.

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Example This example explains the effect of the iridium level in a ruthenium- iridium layer. In the experiment of this example, the complex sample which consists of what carried out electric Metsuki of the ruthenium- iridium on the titanium which was made coarse and cleaned is tested by accelerated life testing. A ruthenium- iridium deposit contains the iridium of various quantity of 25 % of the weight of the maximum abbreviation from 0. The result about the typical sample prepared under the conditions which may be compared is shown in a table.

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[Table]

As for the selected result shown in the table, it will be understood that it is a thing to a rough discrimination test. A certain test which has not been reported to a table showed the bad performance with high level iridium, and showed the good life with low level iridium. However, it will be remarkably dependent on Yoku's kind to be used, Metsuki conditions, covering thickness, processing conditions, and a factor like the one nature of a precipitation thing, and the life of the electrode will change. However, generally it is thought again to the sample which may compare relatively the result shown in a table that it was indicated that a certain tendency pointed out the experiment. As mentioned above, especially the anode of the present invention is effective in electrolysis extraction of nickel. The electrode of the present invention is under the condition which may be compared from a suitable electrolysis solution, and it can also be used in order [ of about about 1.15 to 1.3 V/S C E ] to acquire a nickel cobalt precipitation thing with low anode potential suitably. Although the embodiment with the preferred present invention was indicated, it is not necessary to say that correction is performed and a change can be made, without deviating from the soul and the range of the present invention so that a person skilled in the art may understand easily. It is thought that such correction and change go into the range of the present invention.