WO2018131519A1 - 電解用電極、電解槽、電極積層体及び電極の更新方法 - Google Patents
電解用電極、電解槽、電極積層体及び電極の更新方法 Download PDFInfo
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- WO2018131519A1 WO2018131519A1 PCT/JP2017/047365 JP2017047365W WO2018131519A1 WO 2018131519 A1 WO2018131519 A1 WO 2018131519A1 JP 2017047365 W JP2017047365 W JP 2017047365W WO 2018131519 A1 WO2018131519 A1 WO 2018131519A1
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
- C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm cells
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
- C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
- C25B11/031—Porous electrodes
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
- C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
- C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
Definitions
- the present invention relates to an electrode for electrolysis, an electrolytic cell, an electrode laminate, and an electrode renewal method.
- Ion exchange membrane method salt electrolysis is a method for producing caustic soda, chlorine, and hydrogen by electrolyzing (electrolyzing) salt water using an electrode for electrolysis.
- a technique capable of maintaining a low electrolysis voltage over a long period of time is required to reduce power consumption from the viewpoint of environmental load and energy problems.
- a breakdown of the breakdown of the electrolysis voltage reveals that, in addition to the theoretically required electrolysis voltage, the voltage resulting from the resistance of the ion exchange membrane and the structure resistance of the electrolytic cell, the overvoltage of the anode and cathode as electrolysis electrodes, the anode and cathode It has been clarified that a voltage or the like due to the distance between is included. Further, when electrolysis is continued for a long period of time, a voltage increase or the like caused by various causes such as impurities in salt water may occur.
- Patent Document 1 discloses a technique of an insoluble anode obtained by coating a platinum base metal oxide such as ruthenium on a titanium substrate. This anode is called DSA (registered trademark, Dimension Stable Anode).
- DSA registered trademark, Dimension Stable Anode
- Non-Patent Document 1 describes the transition of soda electrolysis technology using DSA.
- Patent Document 2 a metallic porous plate having a predetermined thickness, pore diameter, and porosity, or an anode using an expanded metal having a predetermined thickness, major diameter, minor diameter, and aperture ratio
- Patent Document 3 proposes an anode which is substantially made of a diamond-shaped metal mesh and has a mesh strand and ratio of openings, a longitudinal distance LWD of the openings, and a width direction SWD of the openings.
- Patent Document 3 discloses that a platinum group metal oxide, magnetite, ferrite, cobalt spinel, or mixed metal oxide can be used as a coating on the surface of the metal mesh having the shape.
- Patent Document 4 a titanium expanded metal or a titanium wire mesh is used as the anode base material, the opening ratio / thickness of the anode base material is set within a predetermined range, and the catalyst is applied to the anode base material.
- the cell voltage during electrolysis can be lowered by adjusting the ratio of the vertical and horizontal apertures of the opening to about half or less of the thickness of the anode in the prior art.
- Attempts have been made to reduce the amount of impurity gas generated by reaction of hydroxide ions diffusing from the cathode chamber through the ion exchange membrane, that is, oxygen gas.
- a method of reducing the voltage during electrolysis in the direction of reducing the thickness of the anode and increasing the aperture ratio of the anode base material is employed.
- Patent Documents 2 to 4 discuss the expanded metal aperture ratio, the distance between the mesh in the longitudinal direction and the width direction, and the like, but the relationship between the anode shape and the electrolysis voltage is fully studied. However, there is a demand for further reduction of the electrolysis voltage. In particular, an anode with a thin anode mesh and a high aperture ratio also causes problems such as insufficient practical strength.
- Patent Document 5 a technique is attempted to lower the anode voltage and reduce the amount of oxygen gas generated by setting the anode thickness to about half or less of the conventional thickness.
- an ion exchange membrane electrolytic cell at an industrial level is used. Since the anode chamber is pressurized and operated, if the anode mesh thickness is too thin, the strength cannot be maintained, and it is necessary to use two expanded metals. Needs further improvement.
- an object of the present invention is to provide an electrode for electrolysis capable of suppressing the voltage and power consumption during electrolysis to a low level and also having practical strength and an electrolytic cell equipped with the electrode for electrolysis. To do.
- the inventors of the present invention have made extensive studies to solve the above problems. As a result, by setting the thickness of the electrode for electrolysis within a specific range and further dividing the sum of the peripheral lengths of the openings of the electrode for electrolysis by the aperture ratio of the electrode for electrolysis as a specific range, The present inventors have found that an electrode for electrolysis can be provided that can suppress the voltage and power consumption of the battery, and has practical strength, and has led to the present invention. In addition, the present inventors have found that the above problem can be solved by making the opening of the electrode for electrolysis a specific shape, and have made the present invention. That is, the present invention is as follows.
- An electrode for electrolysis comprising: The shape of the opening of the electrode for electrolysis is symmetric with respect to the first virtual center line extending in the short direction of the mesh, and with respect to the second virtual center line extending in the long direction of the mesh. Asymmetrical, The electrode for electrolysis whose thickness of the electrode for electrolysis is more than 0.5 mm and 1.2 mm or less.
- a value obtained by dividing the area Sa of the part a by the area Sb of the part b is 1.15 or more
- the electrode for electrolysis according to [11] which is 2.0 or less.
- a value obtained by dividing, by SW, a value St obtained by subtracting the maximum mesh opening in the short direction of the mesh of the opening from the distance SW between the centers in the short direction of the mesh of the opening is [11 or more] ]
- an electrode for electrolysis that can keep voltage and power consumption during electrolysis low and that has practical strength.
- FIG. 1 is a schematic diagram for explaining the relationship between the total perimeter of the opening and the aperture ratio of the electrode for electrolysis assuming that the electrode for electrolysis and the opening are square.
- FIG. 2 is a schematic view according to a typical example of a projection plane obtained by observing the electrode for electrolysis according to one aspect of the present embodiment with a microscope.
- FIG. 3 is an explanatory diagram showing the relationship between the mesh center distance SW in the short direction, the mesh center distance LW in the long mesh direction, and the distance d in the present embodiment, based on the schematic diagram of FIG.
- FIG. 4A is an explanatory view schematically showing a typical example of the shape of the opening of the electrode for electrolysis according to another aspect of the present embodiment.
- FIG. 4A is an explanatory view schematically showing a typical example of the shape of the opening of the electrode for electrolysis according to another aspect of the present embodiment.
- FIG. 4B is an explanatory diagram showing a part a and a part b in FIG.
- FIG. 4C is an explanatory view schematically showing a typical example of the shape of the opening of the conventional electrode for electrolysis.
- FIG. 5 is an explanatory diagram schematically showing an example of the positional relationship between adjacent openings in the electrode for electrolysis according to another aspect of the present embodiment.
- FIG. 6 is a schematic diagram showing an example of a cross section of the electrolytic cell of the present embodiment.
- the present embodiment a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail.
- the following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents.
- the present invention can be implemented with appropriate modifications within the scope of the gist thereof.
- the electrode for electrolysis according to the first aspect of the present embodiment includes a conductive substrate made of a perforated metal plate, and the conductive substrate. Electrolysis electrode provided with at least one catalyst layer formed on the surface, wherein the thickness of the electrolysis electrode is more than 0.5 mm and 1.2 mm or less, and the sum of the peripheral lengths of the openings of the electrolysis electrode A value C obtained by dividing B by an aperture ratio A of the electrode for electrolysis is more than 2 and 5 or less. Since it is configured in this way, the first electrode for electrolysis can keep the voltage and power consumption during electrolysis low, and also has practical strength.
- the first electrode for electrolysis can be used as a chlorine generating electrode particularly suitable for ion exchange membrane salt electrolysis.
- the electrode for electrolysis according to the second aspect of the present embodiment includes a conductive substrate made of a perforated metal plate, and the conductive substrate.
- An electrode for electrolysis comprising at least one catalyst layer formed on the surface, wherein the shape of the opening of the electrode for electrolysis is left and right with respect to the first virtual center line extending in the short direction of the mesh It is symmetrical and is vertically asymmetric with respect to the second virtual center line extending in the long direction of the mesh, and the thickness of the electrode for electrolysis is more than 0.5 mm and not more than 1.2 mm. Since it is configured in this manner, the second electrolysis electrode can also keep the voltage and power consumption during electrolysis low and has practical strength.
- the second electrode for electrolysis can also be used as a chlorine generating electrode suitable for ion exchange membrane salt electrolysis.
- the term “electrode for electrolysis according to the present embodiment” includes the first electrode for electrolysis and the second electrode for electrolysis.
- the conductive substrate is made of a perforated metal plate, and is used in a chlorine gas generating atmosphere in a highly concentrated saline solution close to saturation.
- the material of the conductive substrate is preferably a corrosion-resistant valve metal.
- the valve metal include, but are not limited to, titanium, tantalum, niobium, zirconium, and the like.
- titanium is preferable from the viewpoint of economy and affinity with the catalyst layer.
- the shape of the conductive substrate is not particularly limited as long as it is made of metal and has a flat shape, and examples thereof include expanded metal, a perforated plate, a wire net, and the like.
- expanded metal is used.
- Expanded metal is generally a flat metal plate or metal foil that is flattened by rolling it up to a desired thickness by forming a mesh by slitting with an upper blade and lower blade while slitting. It is. Because continuous hoop processing is possible, production efficiency is high, there is no waste loss of the original plate material, and it is economical, and because it is a monolithic structure, complete electrical conductivity is secured unlike a wire mesh, and it does not unravel .
- the electrode for electrolysis according to the present embodiment is configured by forming at least one catalyst layer on the surface of the conductive base material.
- the thickness of the electrode for electrolysis according to the present embodiment is more than 0.5 mm and 1.2 mm or less. If the thickness of the electrode for electrolysis is a thin substrate of 0.5 mm or less, due to the pressure difference between the anode chamber and the cathode chamber generated during electrolysis or the pressing pressure of the cathode, the anode falls due to the pressure by which the ion exchange membrane presses the anode. As the distance increases, the electrolysis voltage increases.
- the thickness of the electrode for electrolysis exceeds 1.2 mm, the aperture ratio, the SW of the opening (the distance between the centers of the short direction of the mesh of the opening) and the LW (the length of the mesh of the opening) are suitable in this embodiment.
- An expanded metal having a distance between the eye centers cannot be formed.
- the thickness of the electrode for electrolysis is preferably more than 0.5 mm and 1.0 mm or less, more preferably more than 0.5 mm and 0.9 mm or less, and even more preferably 0.7 mm or more and 0.0 mm or less. 9 mm or less.
- the aperture ratio A here refers to the ratio (S B / S A ) of the total area S B of the openings in the projected area S A of either surface of the electrode for electrolysis.
- the total area S B of the opening, in the electrode for electrolysis it is possible that the sum of the projected area of the region cations or electrolytes, etc. is not blocked by the conductive substrate (perforated metal plate).
- the opening is assumed to be square, but the shape of the opening formed in the electrode for electrolysis according to the present embodiment is different.
- FIG. 1A when one square (2 mm ⁇ 2 mm) opening 2 is formed in a square (4 mm ⁇ 4 mm) electrode 1, the opening area is 4 mm 2 and the aperture ratio is 25%, the sum total of the peripheral length of the opening is 8 mm.
- FIG. 1B when four square (1 mm ⁇ 1 mm) opening portions 3 are formed in the electrode 1 having the same shape, the opening area is 4 mm 2, which is the same as FIG.
- the aperture ratio is 25%, which is the same as that shown in FIG. 1A, but the total peripheral length of the opening is 16 mm, which is larger than that shown in FIG.
- the number of openings increases as the sum of the peripheral lengths of the openings increases. That is, the larger the value obtained by dividing the sum of the peripheral lengths of the openings by the opening ratio, the larger the number of openings.
- the gas flow path is dispersed, so that the remaining bubbles are reduced, which contributes to the suppression of voltage rise.
- the method for measuring the total aperture ratio and the total peripheral length of the aperture is not limited to the following.
- an electrode for electrolysis is cut into a square 10 cm wide and 10 cm wide and copied by a copying machine.
- a method of measuring the weight and the peripheral length of each of the paper cut out from the obtained paper, and observing the surface of one of the electrodes for electrolysis with an image observation device such as a microscope Examples include a method of measuring by analyzing image data obtained by photographing a projection plane.
- FIG. 2 schematically shows a typical example of such image data. As shown in FIG. 2, it can be seen that a plurality of openings 20 are formed in the electrode 10 for electrolysis.
- the aperture ratio (%) is calculated by 100 ⁇ (w1 ⁇ w2) / w1 from the weight w1 of the paper before cutting out the opening and the weight w2 of the paper after cutting out all the opening. it can. Further, the total sum of the peripheral lengths can be obtained as the sum of the peripheral lengths of the cut-out portions.
- image data analysis method for example, the use of “Image J” publicly developed by the National Institutes of Health (NIH) for image processing may be used.
- the opening ratio increases or a small number of large openings
- the specific surface area of the electrode for electrolysis is reduced, the apparent current density is increased and the electrolysis voltage is increased.
- the aperture ratio becomes low or the conductive base material has a large number of small openings, which adversely affects the circulation of the electrolyte and the detachment of gas generated at the electrodes. By causing it to occur, the electrolysis voltage may increase.
- the aperture ratio of the electrode for electrolysis is preferably 5% or more and less than 25%, more preferably 7% or more and 20% or less, and more preferably 10% or more and 18% or less. It is particularly preferred. If the aperture ratio of the electrode for electrolysis is 5% or more, the adverse effect such as retention of gas generated at the electrode during electrolysis tends to be effectively eliminated without adversely affecting the circulation of the electrolyte. There is a tendency to reduce the electrolysis voltage. Further, when the aperture ratio of the electrode for electrolysis is less than 25%, the specific surface area of the electrode for electrolysis can be sufficiently secured, that is, the substantial electrode surface facing the ion exchange membrane tends to be sufficiently secured. As a result, the apparent current density can be lowered, and the electrolytic voltage tends to be reduced.
- the peripheral length of one opening of the electrode for electrolysis is preferably 1 mm or more, and more preferably 2.5 mm or more.
- the peripheral length of one opening of the electrode for electrolysis is preferably 4.8 mm or less, and more preferably 4.55 mm or less from the viewpoint of sufficiently securing the specific surface area of the electrode for electrolysis.
- the minor axis SW that is the distance between the meshes in the short direction of the mesh of the opening of the electrode for electrolysis is 1.5 mm or more and 3 mm or less, and the distance between the centers in the long direction of the mesh.
- the certain long diameter LW is preferably 2.5 mm or more and 5 mm or less
- the short diameter SW is 1.5 mm or more and 2.5 mm or less
- the long diameter LW is more preferably 3 mm or more and 4.5 mm or less.
- the SW and LW can be specified as shown in FIG. That is, SW can be specified as a distance connecting the centers of two openings adjacent in the short direction of the mesh.
- LW can be specified as a distance connecting the centers of two openings adjacent to each other in the long direction of the mesh.
- the SW is 1.5 mm or more and the LW is 2.5 mm or more, it is easy to ensure a suitable thickness and aperture ratio in the present embodiment.
- the SW is 3 mm or less and the LW is 5 mm or less, it is easy to secure a suitable aperture ratio range in the present embodiment, that is, it is easy to secure the specific surface area of the electrode for electrolysis. .
- the distance d is calculated as the square root of the value obtained by adding the square of LW to the square of SW, and the smaller this value, the more the mass transfer of gas or the like tends to be promoted. From such a viewpoint, the value of d is preferably 2.9 to 5.8 mm, and more preferably 3.4 to 5.1 mm.
- the electrode for electrolysis it is obtained from the sum B of the peripheral length of the opening, the opening ratio A of the opening, the short diameter SW of the opening, and the long diameter LW of the opening, and is represented by the following formula (1).
- the value E is preferably 0.5 or more, more preferably 0.69 or more, and further preferably 0.69 or more and 1.5 or less.
- E B / (A ⁇ (SW 2 + LW 2 ) 1/2 ) (1)
- (SW 2 + LW 2 ) 1/2 corresponds to d described above.
- the spatial dispersion degree of the opening of the electrode for electrolysis is suitable for the circulation of the electrolyte, and the electrolysis voltage is reduced. It tends to be possible.
- the second electrode for electrolysis is an electrode for electrolysis comprising a conductive base material made of a perforated metal plate and at least one catalyst layer formed on the surface of the conductive base material.
- the shape of the electrode opening is bilaterally symmetric with respect to the first virtual center line extending in the short direction of the mesh, and is vertically asymmetric with respect to the second virtual center line extending in the long direction of the mesh
- the thickness of the electrode for electrolysis is more than 0.5 mm and 1.2 mm or less.
- a typical example of the shape of the opening in the second electrode for electrolysis is shown in FIG.
- the opening 100 in FIG. 4A is symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh.
- the left-right symmetry means that when the opening is divided into a right part and a left part with respect to the first virtual center line, the shape of the right part matches the shape of the left part, that is, the first virtual center line is the reference.
- the right part and the left part are line-symmetric.
- the symmetry can be confirmed by the above-described image analysis.
- the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh.
- the vertical asymmetry means that when the opening is divided into an upper part and a lower part with the second virtual center line as a reference, the shape of the upper part does not match the shape of the lower part, that is, the second virtual center line is the reference.
- the upper part and the lower part are not line-symmetric.
- the symmetry can be confirmed by the above-described image analysis.
- the opening 100 can be divided into an upper part a and a lower part b when the second virtual center line 102 extending in the long direction ⁇ of the mesh is used as a reference. It can be easily confirmed by comparing the shapes of the part a and the part b.
- the present invention is not limited to this assumption, and is included in the second electrode for electrolysis as long as it is an electrode for electrolysis having the above-described configuration.
- a typical shape of the opening in the conventional electrode for electrolysis is one that is bilaterally symmetric with respect to the first virtual center line and that is vertically symmetric with respect to the second virtual center line. It is done.
- the opening 100 ′ is symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh.
- the opening 100 ′ when the second virtual center line 102 extending in the long direction ⁇ of the mesh is used as a reference, the upper part a and the lower part b are symmetrical with respect to the virtual center line 102. It has become.
- the opening typically, the opening has a rhombus shape, and the four sides constituting the opening are positioned at approximately the same distance from the center point of the opening.
- the generated gas typically spherical
- the gas contacts with four sides (that is, four points) constituting the opening. By doing so, it is estimated that the passage resistance tends to increase.
- the second electrode for electrolysis is symmetrical with respect to the first virtual center line and is vertically asymmetric with respect to the second virtual center line, so that gas generated at the electrode is generated.
- the passage resistance tends to be reduced when trying to pass through the opening (typically spherical). That is, there is a tendency that the contact point between the gas generated at the electrode during electrolysis and each side constituting the opening tends to be reduced, so that the gas can be effectively desorbed, and the electrolytic solution is circulated.
- the electrolysis voltage can be reduced without adverse effects.
- the area of the opening with respect to the projected area of 1 cm 2 on either surface is not particularly limited, but is 0.05 cm 2 or more from the viewpoint of further reducing the voltage and power consumption during electrolysis. It is preferable that The number of openings for the projected area of 1 cm 2 is not particularly limited, but is preferably 15 or more from the viewpoint of further reducing the voltage and power consumption during electrolysis. The values of the area of the opening and the number of openings can be measured by the image analysis described above.
- the area Sa of the part a is divided by the area Sb of the part b.
- the value (Sa / Sb) is preferably 1.15 or more and 2.0 or less. In this case, the vertical asymmetry of the processed part described above tends to become more prominent. That is, it can be said from the value of Sa / Sb that the shape of the opening of the electrode for electrolysis is vertically asymmetric with respect to the second virtual center line extending in the long direction of the mesh.
- Sa and Sb correspond to the area of the part a and the area of the part b, respectively, and Sa> Sb.
- the values of Sa and Sb can be measured by the image analysis described above.
- a value St obtained by subtracting the shortest direction maximum opening of the mesh of the opening from the distance SW between the short direction of the mesh of the opening is divided by the SW (St / SW) is preferably 0.4 or more, more preferably more than 0.67 and less than 1.0.
- a plurality of openings are formed in the electrode 300 for electrolysis, and the SW is specified by the distance 310 between the centers in the short direction of the mesh of the openings from two adjacent openings. .
- two adjacent openings means an opening that first touches the first virtual center line when the first virtual center line is extended from a certain opening.
- the LW is specified by the distance 320 between the centers of the meshes of the openings in the longitudinal direction from two adjacent openings.
- two adjacent openings means an opening that first touches the second virtual center line when the second virtual center line is extended from a certain opening.
- the second virtual center line 330 divides the opening into a part a and a part b, and the part a (340) and the virtual center line 330 are used as a reference. It is shown that the part b (350) is vertically asymmetric. Further, in FIG.
- the distance 360 between two openings adjacent in the short direction of the mesh of the opening is the maximum distance in the short direction of the mesh of the opening from the distance SW between the short direction centers of the mesh of the opening. This corresponds to the value St obtained by reducing the opening.
- the shortest direction maximum opening of the mesh of the opening corresponds to the length of the first virtual center line 101 in the example illustrated in FIG.
- the electrode for electrolysis according to the present embodiment is formed by forming at least one catalyst layer on the surface of the above-described conductive substrate.
- the contact surface of the conductive substrate with the catalyst layer is in contact with the catalyst layer.
- a treatment for increasing the surface area of the conductive substrate examples include, but are not limited to, blasting using a cut wire, steel grid, alumina grid or the like; acid treatment using sulfuric acid or hydrochloric acid, or the like.
- an acid treatment method is preferred after forming irregularities on the surface of the conductive substrate by blast treatment.
- the catalyst layer formed on the surface of the conductive base material in the electrode for electrolysis according to the present embodiment, preferably on the surface of the conductive base material subjected to the above-described treatment, is a platinum group in order to lower the electrolysis voltage. It preferably contains an electrode catalyst material such as metal oxide, magnetite, ferrite, cobalt spinel, or mixed metal oxide. From the viewpoint of lowering the voltage during electrolysis, it is more preferable that the ruthenium element, the iridium element, and the titanium element are each in the form of an oxide among the electrode catalyst materials described above. Examples of the ruthenium oxide include, but are not limited to, RuO 2 and the like. Examples of the iridium oxide include, but are not limited to, IrO 2 and the like. Examples of the titanium oxide include, but are not limited to, TiO 2 and the like.
- the ruthenium oxide, iridium oxide, and titanium oxide form a solid solution.
- a solid solution generally refers to a substance in which two or more kinds of substances are dissolved in each other and the whole is a uniform solid phase. Examples of the substance forming the solid solution include a metal simple substance and a metal oxide.
- a metal oxide solid solution suitable for the present embodiment two or more types of metal atoms are irregularly arranged on equivalent lattice points in the unit lattice in the oxide crystal structure.
- a substitution type in which ruthenium oxide, iridium oxide and titanium oxide are mixed with each other, and when viewed from the ruthenium oxide side, the ruthenium atom is substituted by iridium atom or titanium atom or both of them.
- a solid solution is preferred.
- the solid solution state is not particularly limited, and a partial solid solution region may exist. Due to the solid solution, the size of the unit cell in the crystal structure changes slightly. The degree of this change can be confirmed, for example, by measuring the powder X-ray diffraction without changing the diffraction pattern due to the crystal structure and changing the peak position due to the size of the unit cell.
- the content ratio of the ruthenium element, the iridium element, and the titanium element is 0.2 to 3 mol of the iridium element with respect to 1 mol of the ruthenium element, and the titanium element 0.2 to 8 mol is preferable; with respect to 1 mol of ruthenium element, iridium element is 0.3 to 2 mol, and titanium element is more preferably 0.2 to 6 mol; ruthenium element It is particularly preferable that the amount of iridium element is 0.5 to 1.5 mol and that of titanium element is 0.2 to 3 mol with respect to 1 mol.
- Each of iridium, ruthenium, and titanium may be included in the catalyst layer as a form other than an oxide, for example, as a simple metal.
- the catalyst layer in the electrode for electrolysis according to the present embodiment may contain only the above-described ruthenium element, iridium element, and titanium element as constituent elements, or may contain other metal elements besides these. Also good. Specific examples of other metal elements include, but are not limited to, elements selected from tantalum, niobium, tin, platinum, vanadium, and the like. Examples of the existence form of these other metal elements include existence as a metal element contained in an oxide. When the catalyst layer in the present embodiment contains other metal elements, the content ratio is 20 mol% or less as the molar ratio of the other metal elements to the entire metal elements contained in the catalyst layer. Preferably, it is 10 mol% or less.
- the thickness of the catalyst layer is preferably 0.1 to 5 ⁇ m, and more preferably 0.5 to 3 ⁇ m.
- the catalyst layer may be composed of only one layer or two or more layers. When there are two or more catalyst layers, at least one of them may be the catalyst layer in the present embodiment. When there are two or more catalyst layers, at least the innermost layer is preferably the catalyst layer in the present embodiment. When at least the innermost layer is a solid solution formed of ruthenium oxide, iridium oxide, and titanium oxide, the durability of the catalyst layer tends to be further improved. It is also preferable that the catalyst layer in the present embodiment has two or more layers with the same composition or different compositions. Even when there are two or more catalyst layers, the thickness of the catalyst layer in this embodiment is preferably 0.1 to 5 ⁇ m, more preferably 0.5 to 3 ⁇ m, as described above. preferable.
- the electrode for electrolysis according to the present embodiment forms a mesh by forming a mesh on a valve metal flat plate while slitting with an upper blade and a lower blade, and rolling it to a desired thickness by rolling a roll or the like.
- the surface of the conductive substrate is subjected to the surface area increasing treatment, and then a catalyst layer containing ruthenium element, iridium element, and titanium element is formed on the conductive substrate. It can be manufactured by forming.
- the electrode for electrolysis is formed by forming at least one catalyst layer on the surface of the conductive substrate, the thickness is more than 0.5 mm and not more than 1.2 mm, and the peripheral length of the opening
- the thickness of the electrode for electrolysis falls within a range suitable for the present embodiment by adjusting the thickness of the flat plate made of valve metal used as the material of the conductive base material and the rolling strength at the time of flattening processing by rolling by rolling. Can be adjusted. Further, the aperture ratio of the electrode for electrolysis and the short diameter SW that is the distance between the mesh short direction of the opening are a series of forming a mesh by pushing the valve metal flat plate while slitting with the upper blade and the lower blade. In this step, it is possible to adjust the range suitable for the present embodiment by adjusting the step width continuously fed forward by the feed roller in conjunction with the vertical movement of the upper blade.
- the step width when slitting the valve metal flat plate with the upper blade and the lower blade is 0.8 mm or less.
- 0.5 mm or more is preferable from a viewpoint of maintaining the shape of the opening part of this embodiment.
- the major axis LW which is the distance between the mesh length direction centers of the openings, is adjusted to a range suitable for this embodiment by appropriately selecting the upper blade and lower blade molds into which the valve metal flat plate is slit. can do.
- the sum of the peripheral lengths of the openings of the electrode for electrolysis increases and decreases depending on the increase and decrease of the number of openings, it can be adjusted by the number of upper and lower blades into which slits are inserted.
- a perforated plate such as punching metal
- it can be obtained by punching a metal flat plate with a punching press mold.
- the aperture ratio, the sum of the peripheral lengths of the openings, SW and LW can be adjusted within the preferred range of the present embodiment.
- a wire mesh as a conductive base material, it can be obtained by weaving using a plurality of metal wires for wire mesh production obtained by various known methods.
- the aperture ratio and opening By appropriately selecting the weight per unit length of metal wire (denier, equivalent to the thickness of the metal wire) and the number of metal wires woven per unit area of the metal mesh (number of meshes), the aperture ratio and opening The sum of the peripheral lengths of the sections, SW, and LW can be adjusted within the preferred range of this embodiment. Further, the shape related to the second electrolysis electrode tends to be easily obtained by the same control as described above.
- the formation of the catalyst layer on the conductive substrate described above is preferably performed by a thermal decomposition method.
- a coating liquid containing a mixture of the above-described elements (precursor) is applied on a conductive substrate, and then baked in an oxygen-containing atmosphere.
- the catalyst layer can be formed by thermally decomposing these components. According to this method, the electrode for electrolysis can be manufactured with high productivity with a smaller number of steps than the conventional manufacturing method.
- thermal decomposition means that a precursor metal salt or the like is fired in an oxygen-containing atmosphere and decomposed into a metal oxide or metal and a gaseous substance.
- the decomposition product obtained can be controlled by the metal species contained in the precursor blended in the coating liquid as a raw material, the type of metal salt, the atmosphere in which thermal decomposition is performed, and the like.
- thermal decomposition is usually performed in air.
- the range of the oxygen concentration at the time of firing is not particularly limited, and it is sufficient to perform in the air. However, if necessary, air may be circulated in the firing furnace or oxygen may be supplied.
- the ruthenium compound, the iridium compound, and the titanium compound may be oxides, but are not necessarily oxides.
- a metal salt or the like may be used.
- these metal salts include, but are not limited to, any one selected from the group consisting of chloride salts, nitrates, sulfates, and metal alkoxides.
- the metal salt of the ruthenium compound is not limited to the following, and examples thereof include ruthenium chloride and ruthenium nitrate.
- the metal salt of the iridium compound include, but are not limited to, iridium chloride and iridium nitrate.
- it does not limit to the following as a metal salt of a titanium compound For example, titanium tetrachloride etc. are mentioned.
- the above compounds are appropriately selected and used according to the desired metal element ratio in the catalyst layer.
- the coating liquid may further contain a compound other than the compound contained in the above compound. Examples of other compounds include, but are not limited to, metal compounds containing metal elements such as tantalum, niobium, tin, platinum, rhodium, and vanadium; metal elements such as tantalum, niobium, tin, platinum, rhodium, and vanadium; metal elements such as tantalum, niobium, tin, platinum, rhodium, and vanadium
- An organic compound containing The coating liquid is preferably a liquid composition in which the above compound group is dissolved or dispersed in an appropriate solvent.
- the solvent for the coating solution used here can be selected according to the type of the compound. For example, water; alcohols such as butanol can be used.
- the total compound concentration in the coating solution is not particularly limited, but is preferably 10 to 150 g / L from the viewpoint of appropriately
- the method of coating the coating liquid on the surface of the conductive substrate is not limited to the following, but, for example, a dipping method in which the conductive substrate is immersed in the coating liquid, or coating on the surface of the conductive substrate.
- An electrocoating method or the like can be used.
- the roll method and the electrostatic coating method are preferable from the viewpoint of excellent industrial productivity.
- a coating film of the coating liquid can be formed on at least one surface of the conductive substrate.
- the coating film After applying the coating liquid to the conductive substrate, it is preferable to perform a step of drying the coating film as necessary.
- the drying step can be more firmly formed on the surface of the conductive substrate.
- the drying conditions can be appropriately selected depending on the composition of the coating liquid, the solvent type, and the like.
- the drying step is preferably performed at a temperature of 10 to 90 ° C. for 1 to 20 minutes.
- the firing temperature can be appropriately selected depending on the composition of the coating liquid and the solvent type.
- the firing temperature is preferably 300 to 650 ° C.
- the precursor such as ruthenium compound is not sufficiently decomposed, and a catalyst layer containing ruthenium oxide or the like may not be obtained.
- the firing temperature exceeds 650 ° C., the conductive base material may be oxidized, so that the adhesion at the interface between the catalyst layer and the base material may be lowered. This tendency should be emphasized particularly when a titanium substrate is used as the conductive substrate. A longer firing time is preferred.
- the above-mentioned steps of coating, drying and firing the catalyst layer can be repeated a plurality of times to form the catalyst layer in a desired thickness.
- firing can be performed for a longer time if necessary to further improve the stability of the catalyst layer that is extremely chemically, physically and thermally stable.
- the conditions for the long-term firing are preferably about 30 minutes to 4 hours at 400 to 650 ° C.
- the electrode for electrolysis according to the present embodiment has low overvoltage even in the initial stage of electrolysis, and can be electrolyzed with low voltage and low power consumption over a long period of time. Therefore, it can be used for various electrolysis.
- it is preferably used as an anode for chlorine generation, and more preferably used as an anode for salt electrolysis in the ion exchange membrane method.
- the electrolytic cell of the present embodiment includes the electrode for electrolysis according to the present embodiment. That is, the electrolytic cell of this embodiment includes an anode chamber including the electrode for electrolysis according to this embodiment as an anode, a cathode chamber including a cathode, and an ion exchange membrane that separates the anode chamber and the cathode chamber. Prepare. This electrolytic cell has a reduced initial voltage during electrolysis.
- An example of the cross section of the electrolytic cell of this embodiment is schematically shown in FIG.
- the electrolytic bath 200 connects the electrolytic solution 210, a container 220 for containing the electrolytic solution 210, the anode 230 and the cathode 240 immersed in the electrolytic solution 210, the ion exchange membrane 250, and the anode 230 and the cathode 240 to a power source.
- Wiring 260 is provided.
- a space on the anode side partitioned by the ion exchange membrane 250 is referred to as an anode chamber
- a space on the cathode side is referred to as a cathode chamber.
- the electrolytic cell of this embodiment can be used for various electrolysis.
- an aqueous alkali chloride solution such as a 2.5 to 5.5 N (N) aqueous sodium chloride solution (saline solution) or an aqueous potassium chloride solution is provided.
- aqueous alkali hydroxide aqueous solution for example, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, etc.
- water can be used.
- the electrode for electrolysis according to this embodiment is used.
- the ion exchange membrane 250 for example, a fluororesin membrane having an ion exchange group can be used.
- an ion exchange membrane formed by forming a protruding portion (microprojection: delta shape) made of a polymer that forms the ion exchange membrane on the anode side surface of the ion exchange membrane is used as an electrode for electrolysis according to this embodiment. It is preferable to use as an electrolytic cell in combination. Specific examples thereof include “Aciplex” (registered trademark) F6801 (manufactured by Asahi Kasei Corporation).
- ion exchange membrane having a delta shape By using an ion exchange membrane having a delta shape, supply of salt water between the ion exchange membrane and the anode is promoted, and damage to the ion exchange membrane and increase in the sodium chloride concentration in caustic soda tend to be suppressed. Stable electrolytic performance can be maintained by combining the ion exchange membrane having a delta shape and the electrode for electrolysis according to the present embodiment.
- a method for forming a protrusion part For example, it can form by the method etc. which are described in patent 4573715 specification and patent 4708133 specification.
- the cathode 240 is a cathode for hydrogen generation, and an electrode or the like in which a catalyst is coated on a conductive substrate is used.
- a cathode a known one can be adopted. Specifically, for example, nickel, nickel oxide, an alloy of nickel and tin, a combination of activated carbon and oxide, ruthenium oxide, platinum, etc. on a nickel base.
- the structure of the electrolytic cell of this embodiment is not specifically limited, A monopolar type or a bipolar type may be sufficient.
- the material constituting the electrolytic cell is not particularly limited.
- the material for the anode chamber is preferably titanium or the like resistant to alkali chloride and chlorine; the material for the cathode chamber is resistant to alkali hydroxide and hydrogen. Nickel or the like is preferred.
- the electrode for electrolysis (anode 230) according to the present embodiment may be disposed with an appropriate interval between the electrode and the ion exchange membrane 250, or may be disposed in contact with the ion exchange membrane 250. Can be used without problems.
- the cathode 240 may be arranged with an appropriate interval from the ion exchange membrane 250, or even if it is a contact type electrolytic cell (zero gap type electrolytic cell) with no gap between the ion exchange membrane 250, Can be used without any problems.
- the electrolysis conditions of the electrolytic cell of the present embodiment are not particularly limited, and can be operated under known conditions. For example, it is preferable to perform electrolysis by adjusting the electrolysis temperature to 50 to 120 ° C. and the current density to 0.5 to 10 kA / m 2 .
- the electrode for electrolysis which concerns on this embodiment can be used suitably for the use which updates an electrode, when the activity of the catalyst coating electrode existing in the electrolytic cell falls. That is, the electrode renewal method in the present embodiment includes a step of welding the electrode for electrolysis according to the present embodiment onto the existing electrode in the electrolytic cell. As described above, simply by newly welding the electrode for electrolysis according to the present embodiment on the existing electrode, the electrolysis performance of the existing electrode with reduced activity is returned to the level before deterioration or further improved, that is, easily. Can be reactivated.
- the electrode for electrolysis according to the present embodiment welded and the existing electrode in the electrolytic cell can be regarded as a laminate. That is, the electrode laminate of the present embodiment includes the electrode for electrolysis according to the present embodiment and a base electrode different from the electrode for electrolysis.
- the base material electrode here is not specifically limited, Typically, it is the existing electrode in the electrolytic cell mentioned above, Comprising: The electrode which activity fell can be mentioned.
- the thickness B is more than 0.5 mm and not more than 0.65 mm, and the sum B of the peripheral lengths of the openings is defined as the aperture ratio A.
- the electrode for electrolysis according to the present embodiment can lower the electrolysis voltage in salt electrolysis than before. Therefore, according to the electrolytic cell of this embodiment provided with this electrode for electrolysis, the power consumption required for salt electrolysis can be reduced. Furthermore, since the electrode for electrolysis according to the present embodiment has a chemically, physically and thermally stable catalyst layer, it has excellent long-term durability. Therefore, according to the electrolytic cell of this embodiment provided with the electrode for electrolysis, the catalytic activity of the electrode is maintained high for a long time, and it becomes possible to stably produce high-purity chlorine.
- an electrolytic cell comprising an anode cell having an anode chamber and a cathode cell having a cathode chamber was prepared.
- a nickel wire mesh base material coated with a ruthenium oxide catalyst was used as the cathode.
- an expanded base material made of metallic nickel as a current collector was cut out and welded at the same size as the anode, and then a cushion mat knitted with nickel wire was placed on it.
- a cathode was placed.
- a rubber gasket made of EPDM (ethylene propylene diene) was used as the gasket, and an ion exchange membrane was sandwiched between the anode cell and the cathode cell.
- a cation exchange membrane “Aciplex” (registered trademark) F6801 (manufactured by Asahi Kasei Corporation) for salt electrolysis was used.
- the electrolytic voltage was measured by measuring the potential difference between the cathode and the anode. In order to measure the initial electrolysis performance of the anode, the electrolysis voltage was measured after 5 days from the start of electrolysis.
- the electrolysis conditions were a current density of 6 kA / m 2 , a salt water concentration of 205 g / L in the anode cell, a NaOH concentration of 32% by mass in the cathode cell, and a temperature of 90 ° C.
- As a rectifier for electrolysis “PAD36-100LA” (manufactured by Kikusui Electronics Co., Ltd.) was used.
- Example 1 As the conductive base material, a titanium expanded metal having a mesh center distance (SW) of 2.1 mm, a mesh center distance (LW) of 3 mm, and a plate thickness of 0.81 mm was used. The plate thickness was measured with a thickness meter. SW, LW, St, the aperture ratio, and the sum of the peripheral lengths of the openings are images obtained by observing a predetermined range of the surface of the conductive substrate with an image observation device such as a microscope and photographing the projection surface. It was determined by analyzing the data. As a method for analyzing image data, “Image J”, which was developed by the National Institutes of Health (NIH) and used publicly, was used for image processing.
- NASH National Institutes of Health
- the image size used for the image processing was in the range of 8.0 ⁇ 5.3 mm of the conductive substrate. That is, for the openings existing in this range, the distance between the short direction center of the mesh specified for each of the adjacent openings, the distance between the center of the long direction of the mesh, and the mesh of the opening part The value obtained by subtracting the shortest direction maximum opening of the mesh of the opening from the short direction center distance was measured, and the average value thereof was calculated as SW, LW, and St, respectively.
- an aqueous ruthenium chloride solution (manufactured by Tanaka Kikinzoku Co., Ltd., ruthenium concentration 100 g / L) is adjusted to 5 ° C. or less with dry ice so that the element ratio (molar ratio) of ruthenium, iridium and titanium is 25:25:50.
- the coating liquid CL1 is poured into a liquid receiving vat of the coating machine, and the EPDM sponge roll is rotated to suck up and impregnate the coating liquid CL1, and the PVC roll is brought into contact with the upper part of the sponge roll. Arranged. And it applied through the electroconductive base material which gave the pre-treatment between the said EPDM sponge roll and the said PVC roll. Immediately after the coating, the conductive substrate after the coating was passed between two EPDM sponge rolls wound with cloth, and the excess coating solution was wiped off. Then, after drying at 50 ° C. for 10 minutes, baking was performed in the air at 475 ° C. for 10 minutes.
- the cycle consisting of roll coating, drying and firing was repeated a total of 7 times, followed by further firing for 1 hour at 520 ° C. to form a black-brown first catalyst layer on the conductive substrate.
- the coating liquid is changed to CL2
- roll coating is performed in the same manner as when coating is performed using the coating liquid CL1
- drying is performed in the atmosphere.
- Firing was performed at 440 ° C. for 10 minutes.
- it was baked at 440 ° C. for 60 minutes in the atmosphere to produce an electrode for electrolysis.
- the obtained electrode for electrolysis had a thickness of 0.81 mm, an aperture ratio of 7.4%, the number of apertures per projected area of the electrode exceeded 20 / cm 2 , and a value obtained by dividing the sum of the peripheral lengths of the apertures by the aperture ratio.
- the shape of the opening was observed to be the same as that in FIG. 4A, and the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.28, and the value obtained by dividing St by SW was 0.76.
- Example 1 The conductive base material in Example 1 was a titanium expanded metal having a mesh center distance (SW) of 3 mm, a mesh center distance (LW) of 6 mm, and a plate thickness of 1.0 mm. Except for the above, an electrode for electrolysis was produced in the same manner as in Example 1. The obtained electrode for electrolysis had a thickness of 1.0 mm, an aperture ratio of 37.8%, the number of apertures per projected area of the electrode was 13 / cm 2 , and the value obtained by dividing the total perimeter of the aperture by the aperture ratio was 1.06. In addition, the shape of the opening was the same as that in FIG.
- the opening 100 ′ was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 ′ is vertically symmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.03, and the value obtained by dividing St by SW was 0.667.
- Example 2 The conductive substrate in Example 1 is made of titanium having a mesh center distance (SW) of 2.2 mm, a mesh mesh center distance (LW) of 4.2 mm, and a plate thickness of 0.8 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.80 mm, an aperture ratio of 10.9%, the number of apertures per projected area of the electrode was 20 / cm 2 , and the value obtained by dividing the sum of the peripheral lengths of the apertures by the aperture ratio was 3.26.
- the shape of the opening was the same as that shown in FIG.
- the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.64, and the value obtained by dividing St by SW was 0.73.
- Example 3 The conductive base material in Example 1 is made of titanium having a mesh center distance (SW) of 2.3 mm, a mesh mesh center distance (LW) of 3.3 mm, and a plate thickness of 0.83 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.83 mm, an aperture ratio of 9.25%, the number of openings per projected area of the electrode exceeded 20 / cm 2 , and a value obtained by dividing the sum of the peripheral lengths of the openings by the aperture ratio. Was 3.65.
- the shape of the opening was observed to be the same as that in FIG.
- the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.27, and the value obtained by dividing St by SW was 0.70.
- Example 4 The conductive base material in Example 1 is made of titanium having a mesh center distance (SW) of 2.3 mm, a mesh mesh center distance (LW) of 3.3 mm, and a plate thickness of 0.81 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.81 mm, an aperture ratio of 22.1%, the number of apertures per projected area of the electrode exceeded 20 / cm 2 , and a value obtained by dividing the sum of the peripheral lengths of the apertures by the aperture ratio.
- the shape of the opening was observed to be the same as that in FIG.
- the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.28, and the value obtained by dividing St by SW was 0.43.
- Example 5 The conductive base material in Example 1 is made of titanium having a mesh center distance (SW) of 1.6 mm, a mesh mesh center distance (LW) of 3.0 mm, and a plate thickness of 0.56 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.56 mm, an aperture ratio of 17.5%, the number of openings per projected area of the electrode was 43 / cm 2 , and the value obtained by dividing the sum of the peripheral lengths of the openings by the aperture ratio was 3.30.
- the shape of the opening was observed to be the same as that in FIG.
- the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.88, and the value obtained by dividing St by SW was 0.65.
- Example 6 The conductive substrate in Example 1 is made of titanium having a mesh center distance (SW) of 2.1 mm, a mesh center distance (LW) of 3.1 mm, and a plate thickness of 0.81 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.81 mm, an aperture ratio of 15.5%, the number of apertures per projected area of the electrode exceeded 20 / cm 2 , and a value obtained by dividing the sum of the peripheral lengths of the apertures by the aperture ratio.
- the shape of the opening was observed to be the same as that in FIG.
- the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.42, and the value obtained by dividing St by SW was 0.67.
- Example 7 For the titanium expanded metal produced in the same manner as in Example 6 (SW: 2.2 mm, LW: 3.2 mm, plate thickness 0.82 mm), the coating liquid CL1 in Example 1 was treated in the same manner as in Example 1. The first catalyst layer was formed on the conductive substrate. Next, an aqueous ruthenium nitrate solution (manufactured by Furuya Metals Co., Ltd., ruthenium concentration 100 g / wt) so that the element ratio (molar ratio) of ruthenium, iridium, titanium, and vanadium is 21.25: 21.25: 42.5: 15.
- aqueous ruthenium nitrate solution manufactured by Furuya Metals Co., Ltd., ruthenium concentration 100 g / wt
- Titanium tetrachloride manufactured by Wako Pure Chemical Industries, Ltd.
- an aqueous iridium chloride solution manufactured by Tanaka Kikinzoku Co., Ltd., iridium concentration 100 g / L
- Vanadium chloride (III) manufactured by Kishida Chemical Co., Ltd.
- the first firing temperature is 400 ° C.
- the temperature was raised to 450 ° C. and repeated three more times.
- baking was further performed at 520 ° C. for 1 hour to prepare an electrode for electrolysis.
- the obtained electrode for electrolysis had a thickness of 0.82 mm, an aperture ratio of 16.1%, the number of apertures per projected area of the electrode exceeded 20 / cm 2 , and a value obtained by dividing the sum of the peripheral lengths of the apertures by the aperture ratio.
- the shape of the opening was observed to be the same as that in FIG.
- the opening 100 was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh. Further, the opening 100 is vertically asymmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.38, and the value obtained by dividing St by SW was 0.63.
- Example 2 The conductive base material in Example 1 was rolled with a mesh center distance (SW) of 2.3 mm, a mesh center distance (LW) of 3.0 mm, and a sheet thickness of 0.6 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that titanium expanded metal that was not flattened by a roll was used.
- the obtained electrode for electrolysis had a thickness of 0.6 mm, an aperture ratio of 43.3%, and a value obtained by dividing the total peripheral length of the aperture by the aperture ratio was 1.07.
- the shape of the opening was the same as that in FIG. 4C, and the opening 100 ′ was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh.
- the opening 100 ′ is vertically symmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 0.90, and the value obtained by dividing St by SW was 0.45.
- Example 3 The conductive base material in Example 1 is made of titanium having a mesh center distance (SW) of 2.1 mm, a mesh mesh center distance (LW) of 4.0 mm, and a plate thickness of 0.5 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.5 mm, an aperture ratio of 35.7%, and a value obtained by dividing the total peripheral length of the openings by the aperture ratio was 1.78.
- the shape of the opening was the same as that in FIG. 4C, and the opening 100 ′ was symmetrical with respect to the first virtual center line 101 extending in the short direction ⁇ of the mesh.
- the opening 100 ′ is vertically symmetric with respect to the second virtual center line 102 extending in the long direction ⁇ of the mesh. Furthermore, the value obtained by dividing the area Sa of the part a by the area Sb of the part b was 1.10, and the value obtained by dividing St by SW was 0.48.
- the reduction in electrolysis voltage relative to Comparative Example 1 is 35 mV in Example 1, 43 mV in Example 2, 41 mV in Example 3, 8 mV in Example 4, and in Example 5. 42 mV, 19 mV in Example 6, and it was found that both can reduce the electrolysis voltage relative to Comparative Example 1.
- Comparative Examples 2 and 3 the electrolytic voltage increased by 23 mV and 19 mV, respectively, compared to Comparative Example 1.
- the decrease in the electrolysis voltage with reference to Comparative Example 1 is 19 mV in Example 6 and 39 mV in Example 7, and both can reduce the electrolysis voltage relative to Comparative Example 1. I understood.
- the electrode for electrolysis according to this embodiment has a vanadium-containing catalyst layer, the effect of reducing the electrolysis voltage is further increased.
- Example 8 The electrode for electrolysis of Example 5 was used for reactivation of the electrode with reduced activity.
- This base electrode was attached to the rib of the anode chamber of the anode cell by welding.
- the electrolytic voltage at a current density of 6 kA / m 2 of this substrate electrode was increased by 32 mV with respect to Comparative Example 1.
- the electrode for electrolysis of Example 5 was welded as a renewal electrode, and it was set as the electrolytic cell containing an electrode laminated body.
- Example 9 The conductive base material in Example 1 is made of titanium having a mesh center distance (SW) of 2.2 mm, a mesh mesh center distance (LW) of 3.0 mm, and a plate thickness of 0.52 mm.
- An electrode for electrolysis was produced in the same manner as in Example 1 except that expanded metal was used.
- the obtained electrode for electrolysis had a thickness of 0.52 mm, an aperture ratio of 23.3%, and a value obtained by dividing the total peripheral length of the aperture by the aperture ratio was 2.36.
- the above-described electrode for electrolysis was used to reactivate an electrode with reduced activity.
- the base electrode was attached to the rib of the anode chamber of the anode cell by welding.
- the electrolysis voltage at a current density of 6 kA / m 2 of this substrate electrode was increased by 35 mV with respect to Comparative Example 1.
- the above-mentioned electrolysis electrode was welded as a renewal electrode to obtain an electrolytic cell containing an electrode laminate.
- the electrode for electrolysis of the present invention can be suitably used in the field of salt electrolysis because it can keep the voltage and power consumption during electrolysis low and has practical strength.
- it is useful as an anode for salt exchange electrolysis by ion exchange membrane method, and enables high-purity chlorine gas having a low oxygen gas concentration to be produced at low voltage and low power consumption over a long period of time.
- Electrolysis electrode 20 Opening part 100 Opening part 100 'Opening part 101 1st virtual center line 102 2nd virtual center line a Part a b part b 200 Electrolysis Cell for Electrolysis 210 Electrolyte 220 Container 230 Anode (Electrode for Electrolysis) 240 Cathode 250 Ion Exchange Membrane 260 Wiring 300 Electrode for Electrode 310 Distance in Center of Short Mesh Direction of Opening Mesh (Short Diameter SW) 320 Distance between centers of long mesh direction of opening (long diameter LW) 330 Second virtual center line 340 portion a 350 part b 360 Distance between opening and opening in short direction of opening mesh
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Abstract
Description
電解電圧の内訳を詳細に解析すると、理論的に必要な電解電圧以外に、イオン交換膜の抵抗及び電解槽の構造抵抗に起因する電圧、電解用電極である陽極及び陰極の過電圧、陽極と陰極との間の距離に起因する電圧等が含まれることが明らかになっている。また、長期に亘って電解を継続すると、塩水中の不純物等の種々の原因に惹起される電圧上昇等が生じることもある。
例えば、特許文献2には、所定の厚み・孔径・多孔率を有する金属性の多孔板、又は所定の厚み・長径・短径・開口率を有するエクスパンデッドメタルを用いた陽極に対して、陽イオン交換膜の陽極面を可及的に近づけて電解する方法が提案されている。特許文献3には、実質上ダイヤモンド形状の金属メッシュから成り、メッシュのストランド及び開口部の割合、開口部の長手方向間隔LWD及び幅方向間隔SWDを所定の値とした陽極が提案されている。この特許文献3には、該形状を有する金属メッシュの表面上にコーティングとして、白金族金属酸化物、マグネタイト、フェライト、コバルトスピネル、または混合金属酸化物を用いることが出来ると開示されている。
また特許文献4では、陽極基材としてチタン製エクスパンデッドメタルまたはチタン製金網を用い、該陽極基材の開口率・厚みを所定の範囲とすること、及び該陽極基材への触媒塗布後の陽極表面上の凹凸高低差の最大値を所定の範囲とすることによって、電解性能を向上させる技術が提案されている。
さらに特許文献5においては、陽極の厚みを従来の約半分以下とし、かつ開口部の縦方向、横方向の孔開きの比率を調整することで、電解時のセル電圧を下げることができる旨が記載されており、この電極により、陰極室からイオン交換膜を介して拡散する水酸化物イオンが反応して発生する不純物ガス、すなわち、酸素ガス量を低減させる試みがなされている。
このように従来技術では、陽極の厚みを薄くし、陽極基材の開口率を大きくする方向で、電解時の電圧を下げる方策が採用されている。
また、特許文献2~4では、エクスパンデッドメタルの開口率、メッシュの長手方向及び幅方向の各間隔等について検討されているが、陽極の形状と電解電圧との関係については充分に検討されたものではなく、更なる電解電圧の低減化が求められている。特に陽極メッシュ厚みが薄く、かつ開口率の高い陽極では、実用上の強度が不足する等の問題も生じる。
特許文献5では、陽極の厚みを従来の約半分以下とすることによって、陽極の低電圧化と酸素ガス発生量の低減を試みる手法が採られているが、工業レベルでのイオン交換膜電解槽では陰極室から加圧して運転されるため、陽極メッシュ厚みが薄すぎると強度が保てず、エクスパンドメタルを2枚重ねて使用する必要がある等、陽極の強度と電解電圧の低減を満足させるには、更なる改善が必要である。
すなわち、本発明は、以下のとおりである。
[1]
有孔金属製板からなる導電性基材と、
該導電性基材の表面上に形成された少なくとも一層の触媒層と、
を備える電解用電極であって、
前記電解用電極の厚みが0.5mm超1.2mm以下であり、
前記電解用電極の開口部の周辺長の総和Bを前記電解用電極の開口率Aで除した値Cが、2超5以下である、電解用電極。
[2]
前記開口率Aが、5%以上25%未満である、[1]に記載の電解用電極。
[3]
前記開口部のメッシュの短目方向中心間距離SWが1.5以上3以下であり、かつ、前記メッシュの長目方向中心間距離LWが2.5以上5以下である、[1]又は[2]に記載の電解用電極。
[4]
前記電解用電極の厚みが、0.5mm超0.9mm以下である、[1]~[3]のいずれかに記載の電解用電極。
[5]
下記式(1)で表される値Eが、0.5以上である、[1]~[4]のいずれかに記載の電解用電極:
E=B/(A×(SW2+LW2)1/2) (1)
[6]
[1]~[5]のいずれかに記載の電解用電極を陽極として含む陽極室と、
陰極を含む陰極室と、
前記陽極室と前記陰極室とを隔離するイオン交換膜と、
を備える、電解槽。
[7]
前記イオン交換膜の陽極側表面において、当該イオン交換膜を構成するポリマーからなる突出部を有する、[6]に記載の電解槽。
[8]
[1]~[3]のいずれかに記載の電解用電極と、
前記電解用電極とは異なる基材電極と、
を備える、電極積層体。
[9]
前記電解用電極の厚みが、0.5mm超0.65mm以下である、[8]に記載の電極積層体。
[10]
[1]~[3]のいずれかに記載の電解用電極を、電解槽における既設の電極上に溶接する工程を含む、電極の更新方法。
[11]
有孔金属製板からなる導電性基材と、
該導電性基材の表面上に形成された少なくとも一層の触媒層と、
を備える電解用電極であって、
前記電解用電極の開口部の形状が、メッシュの短目方向に伸びる第1の仮想中心線に対して左右対称であり、かつ、メッシュの長目方向に伸びる第2の仮想中心線に対して上下非対称であり、
前記電解用電極の厚みが0.5mm超1.2mm以下である、電解用電極。
[12]
前記開口部を、前記第2の仮想中心線により一方の部分aと他方の部分bに区分したとき、前記部分aの面積Saを前記部分bの面積Sbで除した値が、1.15以上2.0以下である、[11]に記載の電解用電極。
[13]
前記開口部のメッシュの短目方向中心間距離SWから前記開口部のメッシュの短目方向最大目開きを減じた値Stを、前記SWで除した値が、0.4以上である、[11]又は[12]に記載の電解用電極。
以下、「本実施形態に係る電解用電極」と称するときは、第1の電解用電極及び第2の電解用電極を包含するものとする。
本実施形態に係る電解用電極において、導電性基材は、有孔金属製板からなり、飽和に近い高濃度の食塩水中で、塩素ガス発生雰囲気で用いられる。そのため、該導電性基材の材質としては、耐食性のあるバルブ金属が好ましい。バルブ金属としては、以下に限定されないが、例えば、チタン、タンタル、ニオブ、ジルコニウム等が挙げられる。該バルブ金属の中でも、経済性及び触媒層との親和性の観点からチタンが好ましい。
導電性基材の形状としては、金属製で孔を有する平坦状のものであれば特に限定されないが、例えば、エクスパンドメタル、多孔板、金網等の形状が挙げられ、本実施形態においてはエクスパンドメタルが好適に用いられる。エクスパンドメタルとは、一般的に、金属製平板や金属箔に対し、上刃と下刃でスリットを入れながら押し広げてメッシュを形成し、所望の厚みまで圧延ロール掛け等により平坦化加工したものである。連続フープ加工が可能なため生産効率が高く、元の板材の廃棄ロスもなく経済性に優れており、また一体構造のため、金網と異なり完全な電気伝導度が確保され、ほどけることがない。
ここでいう開口率Aとは、電解用電極のいずれか一方の表面の投影面積SAにおける開口部の総面積SBの割合(SB/SA)をいう。開口部の総面積SBとは、電解用電極において、陽イオンや電解液等が導電性基材(有孔金属製板)によって遮断されない領域の投影面積の総計ということができる。
また、ここでいう開口部の周辺長の総和Bとは、電解用電極の単位面積あたりにおける開口部の周辺の長さLiをそれぞれ計測し、該周辺長を単位面積当たりの個数nで積算した値(ΣLi、i=1~n)をいう。
上記(I)について、開口率(%)は、開口部分を切り出す前の紙の重量w1と、開口部分を全て切り出した後の紙の重量w2から、100×(w1-w2)/w1により算出できる。また、周辺長の総和は、開口部分として切り出されたものの各周辺長の合計として求めることができる。
上記(II)について、画像データの解析方法としては、例えば、米国国立衛生研究所(NIH)が開発し公有の「Image J」を画像処理に用いること等が挙げられる。
電解用電極の開口部の周辺長の総和Bを電解用電極の開口率Aで除した値C(=B/A)が2以下であると、開口率が大きくなるか、あるいは少数の大きな開口部を有する電解用電極となり、電解用電極の比表面積が小さくなることで、見かけ上の電流密度が高くなり、電解電圧が上昇する。また上述のCの値が5超であると、開口率が低くなるか、あるいは小さな開口部を多数有する導電性基材となり、電解液の循環や電極で発生するガスの脱離性に悪影響を生じさせることで、電解電圧が上昇する恐れがある。
上記SW及びLWは図3のように特定できる。すなわち、SWは、メッシュの短目方向に隣接する2つの開口部の中心を結んだ距離として特定できる。また、LWはメッシュの長目方向に隣接する2つの開口部の中心を結んだ距離として特定できる。
上記SWが1.5mm以上であり、上記LWが2.5mm以上であると、本実施形態において好適な厚み及び開口率を確保しやすくなる。また、上記SWが3mm以下であり、かつ、上記LWが5mm以下であると、本実施形態において好適な開口率の範囲を確保しやすくなる、すなわち、電解用電極の比表面積を確保しやすくなる。
さらに、図3に示すように、開口部間の距離dも調整することが好ましい。距離dは、SWの二乗にLWの二乗を加えた値の平方根で算出され、この数値が小さいほどガス等の物質移動が促進される傾向にある。かかる観点から、dの値は、2.9~5.8mmであることが好ましく、3.4~5.1mmであることがより好ましい。
E=B/(A×(SW2+LW2)1/2) (1)
式(1)において、(SW2+LW2)1/2は前述のdに対応している。このように、A、B及びdの関係を適切な範囲に調整することにより、開口部の空間的な分散度合が好適となり、電解電圧を低減できる傾向にある。すなわち、電解用電極におけるEの値が0.5以上1.5以下であると、電解液の液循環に対して電解用電極の開口部の空間的な分散度合が好適となり、電解電圧を低減できる傾向にある。
第2の電解用電極における開口部形状の典型例を図4(A)に示す。図4(A)における開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称である。左右対称とは、第1の仮想中心線を基準として開口部を右部分と左部分に分けたとき、右部分の形状が左部分の形状に一致すること、すなわち第1の仮想中心線を基準として右部分と左部分とが線対称であることをいう。左右対称であることは、上述した画像解析により確認することができる。
さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称である。上下非対称とは、第2の仮想中心線を基準として開口部を上部分と下部分に分けたとき、上部分の形状が下部分の形状と一致しないこと、すなわち第2の仮想中心線を基準として上部分と下部分とが線対称とならないことをいう。左右対称であることは、上述した画像解析により確認することができる。例えば、図4(B)に示す例において、開口部100はメッシュの長目方向βに伸びる第2の仮想中心線102を基準としたとき、上側の部分aと下側の部分bに区分でき、部分aと部分bの形状を比較することで容易に確認することができる。
従来の電解用電極における開口部の典型的な形状としては、上記第1の仮想中心線に対して左右対称であり、かつ、上記第2の仮想中心線に対して上下対称であるものが挙げられる。例えば、図4(C)に示す例において、開口部100’は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称である。また、開口部100’において、メッシュの長目方向βに伸びる第2の仮想中心線102を基準としたとき、仮想中心線102を基準として上側の部分aと下側の部分bとは線対称となっている。このような形状である場合、典型的には、開口部は菱形形状であり、当該開口部を構成する4辺は、当該開口部の中心点から略等距離に位置することとなる。このような従来の電解用電極において、発生するガス(典型的には球状である。)が開口部を通過しようとするとき、当該ガスが開口部を構成する4辺(すなわち4点)と接触することで通過抵抗が増加する傾向にあると推測される。すなわち、電解時に電極で発生するガスが開口部に内接して滞留し易い傾向にあり、電解液の液循環に悪影響を与えて電解電圧が上昇するといった問題が生じうる。
これに対して、第2の電解用電極は、第1の仮想中心線に対して左右対称であり、かつ、第2の仮想中心線に対して上下非対称であることにより、電極で発生するガス(典型的には球状である。)が開口部を通過しようとするときの通過抵抗が低減される傾向にあると推測される。すなわち、電解時に電極で発生するガスと開口部を構成する各辺との接触点が少なくなる傾向にあるため、ガスを効果的に脱離させることができる傾向にあり、電解液の液循環に悪影響を与えることなく、電解電圧を低減できるものとなる。
本実施形態に係る電解用電極における導電性基材の表面上に、好ましくは上述の処理を施した導電性基材の表面上に形成される触媒層は、電解電圧を下げるために、白金族金属酸化物、マグネタイト、フェライト、コバルトスピネル、または混合金属酸化物等の電極触媒物質を含むことが好ましい。電解時の電圧をより低く抑える観点から、上述した電極触媒物質の中でも、ルテニウム元素、イリジウム元素及びチタン元素が、それぞれ、酸化物の形態にあることがより好ましい。
ルテニウム酸化物としては、以下に限定されないが、例えばRuO2等が挙げられる。
イリジウム酸化物としては、以下に限定されないが、例えばIrO2等が挙げられる。
チタン酸化物としては、以下に限定されないが、例えばTiO2等が挙げられる。
固溶体とは、一般的に、2種類以上の物質が互いに溶け合い、全体が均一の固相となっているものをいう。固溶体を形成する物質としては、金属単体、金属酸化物等が挙げられる。特に本実施形態に好適な金属酸化物の固溶体の場合には、酸化物結晶構造における単位格子中の等価な格子点上に、2種類以上の金属原子が不規則に配列している。具体的には、ルテニウム酸化物とイリジウム酸化物とチタン酸化物とが相互に混合し、ルテニウム酸化物の側から見れば、ルテニウム原子がイリジウム原子若しくはチタン原子又はこれらの双方によって置換された置換型固溶体であることが好ましい。その固溶状態は特に限定されず、部分固溶の領域が存在していてもよい。
固溶によって、結晶構造における単位格子の大きさがわずかに変化する。この変化の度合いは、例えば、粉末X線回折の測定において、結晶構造に起因する回折パターンは変化せず、単位格子の大きさに起因するピーク位置が変化すること等から確認することができる。
本実施形態における触媒層が、他の金属元素を含んでいる場合、その含有割合は、触媒層に含まれる金属元素の全部に対する他の金属元素のモル比として、20モル%以下であることが好ましく、10モル%以下であることがより好ましい。
本実施形態における触媒層の厚さは、0.1~5μmであることが好ましく、0.5~3μmであることがより好ましい。触媒層の厚さを上述の下限値以上とすることにより、初期電解性能を十分に維持できる傾向にある。また触媒層の厚みを上述の上限値以下とすることにより、経済性に優れた電解用電極が得られる傾向にある。触媒層の厚みは、基材断面を切断し、光学顕微鏡や電子顕微鏡により計測することができる。
触媒層が二層以上である場合には、そのうちの少なくとも一層が本実施形態における触媒層であればよい。触媒層が二層以上である場合には、少なくとも最内層が本実施形態における触媒層であることが好ましい。少なくとも最内層が、ルテニウム酸化物、イリジウム酸化物、及びチタン酸化物から形成される固溶体であることにより、触媒層の耐久性が一層向上する傾向にある。本実施形態における触媒層を、同じ組成又は異なる組成で二層以上有している態様も好ましい。
触媒層が二層以上である場合であっても、本実施形態における触媒層の厚さは、上記のとおり、0.1~5μmであることが好ましく、0.5~3μmであることがより好ましい。
次に、本実施形態に係る電解用電極の製造方法について、導電性基材としてエクスパンドメタルを用いる場合を例にして詳細に説明する。
本実施形態に係る電解用電極は、導電性基材として、バルブ金属製平板に上刃と下刃でスリットを入れながら押し広げてメッシュを形成し、所望の厚みまで圧延ロール掛け等により圧延して平坦化加工したエクスパンドメタルを用い、該導電性基材に、上述の表面積増大化処理を施した後、該導電性基材上に、ルテニウム元素、イリジウム元素、及びチタン元素を含む触媒層を形成することにより、製造することができる。
また、電解用電極の開口率と、開口部のメッシュ短目方向中心間距離である短径SWは、バルブ金属製平板に上刃と下刃でスリットを入れながら押し広げてメッシュを形成する一連の工程において、上刃の上下運動に連動して送りローラーによって連続的に前方へ送る刻み幅を調整することによって、本実施形態に好適な範囲に調整することができる。すなわち、本実施形態の開口部の分散の程度を調整する観点から、バルブ金属製平板に上刃と下刃でスリットを入れる際の刻み幅を0.8mm以下に調整することが好ましい。また、本実施形態の開口部の形状を維持する観点から0.5mm以上が好ましい。
さらに、開口部のメッシュ長目方向中心間距離である長径LWは、バルブ金属製平板にスリットを入れる上刃と下刃の型を適切に選択することにより、本実施形態に好適な範囲に調整することができる。
さらにまた、電解用電極の開口部の周辺長の総和は、開口部の数の増減に依存して増減することから、スリットを入れる上刃と下刃の数等により調整できる。
一方、パンチングメタル等の多孔版を導電性基材として採用する場合は、金属の平板に対して、パンチングプレスの金型で穴あけ加工を施して得ることができ、その際に、例えば、当該金型の形状や配置を適切に選択することにより、開口率、開口部の周辺長の総和、SW及びLWを本実施形態の好適な範囲に調整することができる。
さらに、金網を導電性基材として採用する場合は、種々公知の方法により得られた金網製造用の金属線を複数使用して織り込むことによって得ることができ、その際に、例えば、金網製造用の金属線の単位長さ当たりの重量(デニール、金属線の太さに相当)や、金網の単位面積当たりに織り込む金属線の本数(メッシュ数)を適切に選択することにより、開口率、開口部の周辺長の総和、SW及びLWを本実施形態の好適な範囲に調整することができる。また、上記同様の制御により、第2の電解用電極に係る形状が得られやすくなる傾向にある。
熱分解法による製造方法では、導電性基材上に、上記元素を含有する化合物(前駆体)の混合物を含む塗工液を塗工した後、酸素含有雰囲気下で焼成し、塗工液中の成分を熱分解させることにより、触媒層を形成することができる。この方法によると、従来の製造方法よりも少ない工程数で、高い生産性で、電解用電極を製造することができる。
ルテニウム化合物の金属塩としては、以下に限定されないが、例えば、塩化ルテニウム、硝酸ルテニウム等が挙げられる。
イリジウム化合物の金属塩としては、以下に限定されないが、例えば、塩化イリジウム、硝酸イリジウム等が挙げられる。
チタン化合物の金属塩としては、以下に限定されないが、例えば、四塩化チタン等が挙げられる。
塗工液には、上記化合物に含まれる化合物以外の他の化合物を、更に含んでいてもよい。他の化合物としては、以下に限定されないが、例えば、タンタル、ニオブ、スズ、白金、ロジウム、バナジウム等の金属元素を含有する金属化合物;タンタル、ニオブ、スズ、白金、ロジウム、バナジウム等の金属元素を含有する有機化合物等が挙げられる。
塗工液は、上記の化合物群が適当な溶媒に溶解又は分散されて成る液体状の組成物であることが好ましい。ここで使用される塗工液の溶媒としては、上記化合物の種類に応じて選択できる。例えば、水;ブタノール等のアルコール類等を用いることができる。塗工液中の総化合物濃度は、特に限定されないが、触媒層の厚さを適正に制御するとの観点から、10~150g/Lであることが好ましい。
導電性基材に塗工液を塗工した後、必要に応じて、塗膜を乾燥させる工程を行うことが好ましい。この乾燥工程により、塗膜をより強固に導電性基材の表面に形成することができる。乾燥条件は、塗工液の組成、溶媒種等によって適宜選択することができる。乾燥工程は、10~90℃の温度において1~20分間行うことが好ましい。
焼成時間は、長い方が好ましい。一方、電極の生産性の観点からは、焼成時間が過度に長くなりすぎないように調整することが好ましい。これらを勘案すると、1回の焼成時間は、5~60分間であることが好ましい。
本実施形態の電解槽は、本実施形態に係る電解用電極を備えるものである。すなわち、本実施形態の電解槽は、本実施形態に係る電解用電極を陽極として含む陽極室と、陰極を含む陰極室と、前記陽極室と前記陰極室とを隔離するイオン交換膜と、を備える。この電解槽は、電解する際の初期電圧が低減されたものである。本実施形態の電解槽の断面の一例を図6に模式的に示す。
本実施形態の電解槽に供給する電解液210としては、例えば、陽極室には、2.5~5.5規定(N)の塩化ナトリウム水溶液(食塩水)、塩化カリウム水溶液等の塩化アルカリ水溶液を、陰極室には、希釈した水酸化アルカリ水溶液(例えば水酸化ナトリウム水溶液、水酸化カリウム水溶液等)又は水を、それぞれ使用することができる。
イオン交換膜250としては、例えば、イオン交換基を有するフッ素樹脂膜等を使用できる。イオン交換膜の中でも、イオン交換膜の陽極側表面にイオン交換膜を形成するポリマーからなる突出部(微小突起:デルタ形状)を形成させてなるイオン交換膜を、本実施形態に係る電解用電極と組み合わせて、電解槽として用いることが好ましい。その具体例として、例えば「Aciplex」(登録商標)F6801(旭化成株式会社製)等を挙げることができる。
本実施形態に係る電解用電極(陽極230)は、イオン交換膜250との間に適当な間隔を設けて配置してもよいし、イオン交換膜250と接触して配置されていても、何ら問題なく使用できる。陰極240は、イオン交換膜250と適当な間隔を設けて配置してもよいし、イオン交換膜250との間に間隔がない接触型の電解槽(ゼロギャップ式電解槽)であっても、何ら問題なく使用できる。
本実施形態の電解槽の電解条件については特に限定されず、公知の条件で運転することができる。例えば、電解温度を50~120℃、電流密度を0.5~10kA/m2に調整して、電解を実施することが好ましい。
本実施形態に係る電解用電極は、電解槽に既設の触媒被覆電極の活性が低下した際に、電極を更新する用途に好適に用いることができる。すなわち、本実施形態における電極の更新方法は、本実施形態に係る電解用電極を、電解槽における既設の電極上に溶接する工程を含む。このように、本実施形態に係る電解用電極を既存の電極上に新たに溶接するだけで、活性が低下した既設電極における電解性能を劣化前の水準に戻す、またはさらに向上させる、すなわち、容易に再活性化させることが可能である。そのため、従来は、活性の低下した既存の電極を更新する際に、既存の電極を電解槽から剥ぎ取る工程、さらに新たな電極を溶接する工程、の2つの工程を経ていた電極更新時の負荷を軽減できる。
上記のようにして、溶接された本実施形態に係る電解用電極と、電解槽における既設の電極とは、積層体とみなすことができる。すなわち、本実施形態の電極積層体は、本実施形態に係る電解用電極と、前記電解用電極とは異なる基材電極と、を備えるものである。ここでいう基材電極は特に限定されないが、典型的には、上述した電解槽における既設の電極であって、活性が低下した電極を挙げることができる。
なお、電解用電極の再活性化に好適な、本実施形態に係る電解用電極としては、厚みが0.5mm超0.65mm以下であり、かつ開口部の周辺長の総和Bを開口率Aで除した値C(=B/A)が2より大きく5以下であることが好ましい。厚みが上述の範囲であると、既存の電極上に新たに溶接する際に溶接し易く、既存の電解槽の内部構造・使用部品等を特に変更することなく、電解性能を劣化前の水準に戻す、またはさらに向上させる、すなわち、再活性化させることが可能である。すなわち、本実施形態の電極積層体において、電解用電極の厚みが0.5mm超0.65mm以下であることが好ましい。
更に本実施形態に係る電解用電極は、化学的、物理的、及び熱的に極めて安定な触媒層を有するため、長期の耐久性に優れる。よって、該電解用電極を備える本実施形態の電解槽によれば、長時間に亘って電極の触媒活性が高く維持され、高純度の塩素を安定して製造することが可能となる。
先ず、実施例及び比較例における各評価方法について、以下に示す。
電解セルとして、陽極室を有する陽極セルと、陰極室を有する陰極セルと、を具備する電解セルを用意した。
各実施例及び比較例で準備した電解用電極を所定のサイズ(95×110mm=0.01045m2)に切り出したものを試験用電極とし、該試験用電極を溶接によって陽極セルの陽極室のリブに装着して、陽極として用いた。
陰極としては、ニッケル製の金網基材の上に酸化ルテニウムの触媒被覆を行ったものを用いた。先ず、陰極セルの陰極室のリブ上に、集電体として金属ニッケル製のエキスパンド基材を、陽極と同じサイズで切り出して溶接した後、ニッケル製ワイヤーを編んだクッションマットを乗せ、その上に陰極を配置した。
ガスケットとしては、EPDM(エチレンプロピレンジエン)製のゴムガスケットを用い、陽極セルと陰極セルとの間にイオン交換膜を挟んだ。このイオン交換膜としては、食塩電解用の陽イオン交換膜「Aciplex」(登録商標)F6801(旭化成株式会社製)を用いた。
導電性基材として、メッシュの短目方向中心間距離(SW)が2.1mm、メッシュの長目方向中心間距離(LW)が3mm、板厚0.81mmのチタン製エクスパンドメタルを用いた。上記板厚は厚み計で測定した。また、SW、LW、St、開口率、及び開口部の周辺長の総和の値は、導電性基材の表面の所定範囲をマイクロスコープ等の画像観察機器で観察し、投影面を撮影した画像データを解析することにより求めた。画像データの解析方法として、米国国立衛生研究所(NIH)が開発し公有の「Image J」を画像処理に用いた。画像処理に用いた画像サイズは、導電性基材の8.0×5.3mmの範囲とした。すなわち、この範囲に存在する開口部を対象として、隣接する開口部の各々に対して特定されるメッシュの短目方向中心間距離、メッシュの長目方向中心間距離、及び、開口部のメッシュの短目方向中心間距離から前記開口部のメッシュの短目方向最大目開きを減じた値を測定し、これらの平均値を算出して、それぞれSW、LW及びStとした。以下、各実施例及び比較例における導電性基材及び電解用電極についても、上記と同様にSW、LW、St、開口率A、開口部の周辺長の総和B、開口部1つの周辺長、E(=B/(A×(SW2+LW2)1/2))及び厚みの値を求めることとした。このエクスパンドメタルを、大気中540℃で4時間焼成し、表面に酸化被膜を形成させた後、25質量%硫酸中において85℃で4時間酸処理を行い、導電性基材の表面に細かい凹凸を設ける前処理を施した。
次に、ルテニウムとイリジウムとチタンとの元素比(モル比)が25:25:50になるように、塩化ルテニウム水溶液(田中貴金属社製、ルテニウム濃度100g/L)をドライアイスで5℃以下に冷却及び撹拌しながら、四塩化チタン(キシダ化学社製)を少量ずつ加えた後、更に塩化イリジウム水溶液(田中貴金属社製、イリジウム濃度100g/L)を少量ずつ加えて、総金属濃度が100g/Lの水溶液である塗工液CL1を得た。一方で、ルテニウムとチタンとの元素比(モル比)が35:65になるように、上述の塩化ルテニウム水溶液と四塩化チタンを、上述と同様の混合方法によって、総金属濃度が100g/Lの水溶液である塗工液CL2を得た。
上記のロール塗工、乾燥、及び焼成から成るサイクルを合計7回繰り返し行い、次いで520℃における1時間の焼成を更に行うことにより、導電性基材上に黒褐色の第一触媒層を形成した。この第一触媒層を形成した基材に対して、塗工液をCL2に代える以外は、塗工液CL1を用いて塗工した時と同様にロール塗工、次いで乾燥を実施し、大気中、440℃において10分間、焼成を行った。最後に大気中、440℃において60分間焼成し、電解用電極を作製した。
得られた電解用電極は、厚み0.81mm、開口率7.4%、電極の投影面積当たりの開口部数は20個/cm2超、開口部の周辺長の総和を開口率で除した値は4.54であった。また、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.28、StをSWで除した値は0.76であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が3mm、メッシュの長目方向中心間距離(LW)が6mm、板厚1.0mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み1.0mm、開口率37.8%、電極の投影面積当たりの開口部数は13個/cm2、開口部の周辺長の総和を開口率で除した値は1.06であった。また、開口部の形状は図4(C)と同様の形状が観察され、開口部100’は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100’は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.03、StをSWで除した値は0.667であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.2mm、メッシュの長目方向中心間距離(LW)が4.2mm、板厚0.8mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.80mm、開口率10.9%、電極の投影面積当たりの開口部数は20個/cm2、開口部の周辺長の総和を開口率で除した値は3.26であった。また 、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.64、StをSWで除した値は0.73であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.3mm、メッシュの長目方向中心間距離(LW)が3.3mm、板厚0.83mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.83mm、開口率9.25%、電極の投影面積当たりの開口部数は20個/cm2超、開口部の周辺長の総和を開口率で除した値は3.65であった。また、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.27、StをSWで除した値は0.70であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.3mm、メッシュの長目方向中心間距離(LW)が3.3mm、板厚0.81mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.81mm、開口率22.1%、電極の投影面積当たりの開口部数は20個/cm2超、開口部の周辺長の総和を開口率で除した値は2.05であった。また、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.28、StをSWで除した値は0.43であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が1.6mm、メッシュの長目方向中心間距離(LW)が3.0mm、板厚0.56mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.56mm、開口率17.5%、電極の投影面積当たりの開口部数は43個/cm2、開口部の周辺長の総和を開口率で除した値は3.30であった。また、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.88、StをSWで除した値は0.65であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.1mm、メッシュの長目方向中心間距離(LW)が3.1mm、板厚0.81mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.81mm、開口率15.5%、電極の投影面積当たりの開口部数は20個/cm2超、開口部の周辺長の総和を開口率で除した値は2.72であった。また、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.42、StをSWで除した値は0.67であった。
実施例6と同様に作製したチタン製エクスパンドメタル(SW:2.2mm、LW:3.2mm、板厚0.82mm)に対し、実施例1における塗工液CL1を実施例1と同様の方法で塗工し、上記導電性基材上に第一触媒層を形成した。
次に、ルテニウムとイリジウムとチタンとバナジウムとの元素比(モル比)が21.25:21.25:42.5:15になるように、硝酸ルテニウム水溶液(フルヤ金属社製、ルテニウム濃度100g/L)をドライアイスで5℃以下に冷却及び撹拌しながら、四塩化チタン(和光純薬社製)を少量ずつ加えた後、更に塩化イリジウム水溶液(田中貴金属社製、イリジウム濃度100g/L)及び塩化バナジウム(III)(キシダ化学社製)を少量ずつ加えて、総金属濃度が100g/Lの水溶液である塗工液CL3を得た。上記第一触媒層を形成した基材に対して、塗工液CL3を用いて実施例1と同様にロール塗工、乾燥、及び焼成から成るサイクルを、1回目の焼成温度を400℃とし、次いで450℃に昇温して更に3回繰り返し行い、最後に520℃における1時間の焼成を更に行うことにより、電解用電極を作製した。
得られた電解用電極は、厚み0.82mm、開口率16.1%、電極の投影面積当たりの開口部数は20個/cm2超、開口部の周辺長の総和を開口率で除した値は2.73であった。また、開口部の形状は図4(A)と同様の形状が観察され、開口部100は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下非対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.38、StをSWで除した値は0.63であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.3mm、メッシュの長目方向中心間距離(LW)が3.0mm、板厚0.6mmで、圧延ロールによる平坦化を実施していないチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.6mm、開口率43.3%、開口部の周辺長の総和を開口率で除した値は1.07であった。また、開口部の形状は図4(C)と同様の形状が観察され、開口部100’は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100’は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は0.90、StをSWで除した値は0.45であった。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.1mm、メッシュの長目方向中心間距離(LW)が4.0mm、板厚0.5mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.5mm、開口率35.7%、開口部の周辺長の総和を開口率で除した値は1.78であった。また、開口部の形状は図4(C)と同様の形状が観察され、開口部100’は、メッシュの短目方向αに伸びる第1の仮想中心線101に対して左右対称であった。さらに、開口部100’は、メッシュの長目方向βに伸びる第2の仮想中心線102に対して上下対称であった。さらにまた、部分aの面積Saを部分bの面積Sbで除した値は1.10、StをSWで除した値は0.48であった。
実施例1~6及び比較例1~3でそれぞれ作製した電解用電極を用いて、イオン交換膜法食塩電解試験を実施した。その結果を表1に示す。
なお表1において、導電性基材として用いるエクスパンドメタルに対し、圧延ロールによる平坦化を実施したものを「FR化○」、実施していないものを「FR化×」と記した。また、比較例1を基準とした電解電圧の低減分を「効果:ΔV」の正の値とした。
一方、比較例2、3においては、比較例1に対してそれぞれ、23mV、19mV、電解電圧が増大した。
実施例5の電解用電極を、活性の低下した電極の再活性化に用いた。活性の低下した電極として、セミコマーシャルプラントの電解槽で6.9年通電した比較例1と同様に作製した電解用電極を、所定のサイズ(95×110mm=0.01045m2)に切り出したものを基材電極とし、この基材電極を溶接によって陽極セルの陽極室のリブに装着した。この基材電極の電流密度6kA/m2における電解電圧は、比較例1を基準として32mV上昇していた。この基材電極の上に、実施例5の電解用電極を更新用電極として溶接し、電極積層体を含む電解槽とした。
実施例1における導電性基材を、メッシュの短目方向中心間距離(SW)が2.2mm、メッシュの長目方向中心間距離(LW)が3.0mm、板厚0.52mmのチタン製エクスパンドメタルとした以外は、実施例1と同様の方法により、電解用電極を作製した。
得られた電解用電極は、厚み0.52mm、開口率23.3%、開口部の周辺長の総和を開口率で除した値は2.36であった。
上述の電解用電極を、活性の低下した電極の再活性化に用いた。活性の低下した電極として、製造プラントの電解槽で7.1年通電した比較例1と同様に作製した電解用電極を所定のサイズ(95×110mm=0.01045m2)に切り出したものを基材電極とし、この基材電極を溶接によって陽極セルの陽極室のリブに装着した。この基材電極の電流密度6kA/m2における電解電圧は、比較例1を基準として35mV上昇していた。この基材電極の上に、上記の電解用電極を更新用電極として溶接し、電極積層体を含む電解槽とした。
2,3 開口部
10 電解用電極
20 開口部
100 開口部
100’ 開口部
101 第1の仮想中心線
102 第2の仮想中心線
a 部分a
b 部分b
200 電気分解用電解槽
210 電解液
220 容器
230 陽極(電解用電極)
240 陰極
250 イオン交換膜
260 配線
300 電解用電極
310 開口部のメッシュの短目方向中心間距離(短径SW)
320 開口部のメッシュの長目方向中心間距離(長径LW)
330 第2の仮想中心線
340 部分a
350 部分b
360 開口部のメッシュの短目方向の開口部と開口部との間の距離
Claims (13)
- 有孔金属製板からなる導電性基材と、
該導電性基材の表面上に形成された少なくとも一層の触媒層と、
を備える電解用電極であって、
前記電解用電極の厚みが0.5mm超1.2mm以下であり、
前記電解用電極の開口部の周辺長の総和Bを前記電解用電極の開口率Aで除した値Cが、2超5以下である、電解用電極。 - 前記開口率Aが、5%以上25%未満である、請求項1に記載の電解用電極。
- 前記開口部のメッシュの短目方向中心間距離SWが1.5以上3以下であり、かつ、前記メッシュの長目方向中心間距離LWが2.5以上5以下である、請求項1又は2に記載の電解用電極。
- 前記電解用電極の厚みが、0.5mm超0.9mm以下である、請求項1~3のいずれか一項に記載の電解用電極。
- 下記式(1)で表される値Eが、0.5以上である、請求項1~4のいずれか一項に記載の電解用電極:
E=B/(A×(SW2+LW2)1/2) (1) - 請求項1~5のいずれか一項に記載の電解用電極を陽極として含む陽極室と、
陰極を含む陰極室と、
前記陽極室と前記陰極室とを隔離するイオン交換膜と、
を備える、電解槽。 - 前記イオン交換膜の陽極側表面において、当該イオン交換膜を構成するポリマーからなる突出部を有する、請求項6に記載の電解槽。
- 請求項1~3のいずれか一項に記載の電解用電極と、
前記電解用電極とは異なる基材電極と、
を備える、電極積層体。 - 前記電解用電極の厚みが、0.5mm超0.65mm以下である、請求項8に記載の電極積層体。
- 請求項1~3のいずれか一項に記載の電解用電極を、電解槽における既設の電極上に溶接する工程を含む、電極の更新方法。
- 有孔金属製板からなる導電性基材と、
該導電性基材の表面上に形成された少なくとも一層の触媒層と、
を備える電解用電極であって、
前記電解用電極の開口部の形状が、メッシュの短目方向に伸びる第1の仮想中心線に対して左右対称であり、かつ、メッシュの長目方向に伸びる第2の仮想中心線に対して上下非対称であり、
前記電解用電極の厚みが0.5mm超1.2mm以下である、電解用電極。 - 前記開口部を、前記第2の仮想中心線により一方の部分aと他方の部分bに区分したとき、前記部分aの面積Saを前記部分bの面積Sbで除した値が、1.15以上2.0以下である、請求項11に記載の電解用電極。
- 前記開口部のメッシュの短目方向中心間距離SWから前記開口部のメッシュの短目方向最大目開きを減じた値Stを、前記SWで除した値が、0.4以上である、請求項11又は12に記載の電解用電極。
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- 2017-12-28 EP EP17891083.2A patent/EP3569740A4/en active Pending
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JP7236568B2 (ja) | 2019-06-18 | 2023-03-09 | ティッセンクルップ・ウーデ・クロリンエンジニアズ ゲー エム ベー ハー | 電解用電極および電解装置 |
JP7464313B1 (ja) | 2023-01-20 | 2024-04-09 | ウェスコ エレクトロード シーオーエルティーディー | イオン交換膜法クロルアルカリ電解用電極、その製造方法及びそれを用いたゼロギャップ型イオン交換膜電解槽 |
Also Published As
Publication number | Publication date |
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EP3569740A1 (en) | 2019-11-20 |
US20190360112A1 (en) | 2019-11-28 |
JP6778459B2 (ja) | 2020-11-04 |
KR102349667B1 (ko) | 2022-01-12 |
KR20190088067A (ko) | 2019-07-25 |
CN110023541B (zh) | 2022-02-08 |
KR102422917B1 (ko) | 2022-07-21 |
CN114351178A (zh) | 2022-04-15 |
JPWO2018131519A1 (ja) | 2019-11-07 |
TW201829847A (zh) | 2018-08-16 |
JP6956842B2 (ja) | 2021-11-02 |
CN110023541A (zh) | 2019-07-16 |
BR112019013822A2 (pt) | 2020-01-21 |
KR20210044912A (ko) | 2021-04-23 |
EP3569740A4 (en) | 2020-04-08 |
TWI666343B (zh) | 2019-07-21 |
JP2021008672A (ja) | 2021-01-28 |
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