Abstract: A compound electrode incorporating a lead substrate utilizes the lead as a support structure. This support structure provides a surface that engages a valve metal expanded metal mesh. The mesh member has a front and back surface with the back surface facing the lead support structure. At least the front surface of the mesh member is an active surface. Securing of the mesh member to the lead support structure in electrical connection permits the lead support structure to serve as a current distributor for the mesh member. The mesh member may engage the surface of the lead support structure by pressing or rolling the mesh onto the lead. Other engagement means can include the use of fasteners, or welding and the like. The resulting structure can be particularly useful as an electrode assembly for use in an electrolytic cell that serves for the electrowinning of a metal.

Abstract: A compound electrode incorporating a lead substrate utilizes the lead as a support structure. This support structure provides a surface that engages a mesh member, e.g., a valve metal expanded metal mesh. The mesh member has a front and back surface with the back surface facing the lead support structure. At least the front surface of the mesh member is an active surface. Securing of the mesh member to the lead support structure in electrical connection permits the lead support structure to serve as a current distributor for the mesh member. The mesh member may engage the surface of the lead support structure as by pressing or rolling the mesh onto the lead. Other engagement means can include the use of fasteners, or welding and the like. The resulting structure can be particularly useful as an electrode assembly for use in an electrolytic cell that serves for the electrowinning of a metal.

Abstract: A method of preparing electrodes is now described, which electrodes have enhanced adhesion of subsequently applied coatings combined with excellent coating service life. In the method, a substrate metal, such as a valve metal as represented by titanium, is provided with a highly desirable rough surface characteristic for subsequent coating application. This can be achieved by various operations including etching to ensure a roughened surface morphology. In subsequent operations, a barrier layer is provided on the surface of enhanced morphology. This may be achieved by operations including heating, as well as including thermal decomposition of a layer precursor. Subsequent coatings provide enhanced lifetime even in the most rugged commercial environments.

Abstract: An electrode, electrochemical cell, and electrochemical processes are disclosed. The electrode is a porous, multi-layered electrode which can have an element in flexible, strip form wound around a central, usually flat plate core, which core may serve as a current distributor. In any form, each layer can be represented by a very thin, highly flexible metal mesh. This can be a fine, as opposed to a coarse, mesh which has extremely thin strands and small voids. The electrode will have an active coating. For utilizing this electrode, the cell in one form will be a monopolar cell providing upward, parallel electrolyte flow through the porous, multi-layered electrode. A representative cell can have such electrode at least substantially filling an electrode chamber. The cells can be contained in a cell box that will provide the desired flow-through relationship for the electrolyte to the electrode.

Abstract: An electrode, electrochemical cell, and electrochemical processes are disclosed. The electrode is a porous, multi-layered electrode which can have an element in flexible, strip form wound around a central, usually flat plate core, which core may serve as a current distributor. In any form, each layer can be represented by a very thin, highly flexible metal mesh. This can be a fine, as opposed to a coarse, mesh which has extremely thin strands and small voids. The electrode will have an active coating. For utilizing this electrode, the cell in one form will be a monopolar cell providing upward, parallel electrolyte flow through the porous, multi-layered electrode. A representative cell can have such electrode at least substantially filling an electrode chamber. The cells can be contained in a cell box that will provide the desired flow-through relationship for the electrolyte to the electrode.

Abstract: An electrode, electrochemical cell, and electrochemical processes are disclosed. The electrode is a porous, multi-layered electrode which can have an element in flexible, strip form wound around a central, usually flat plate core, which core may serve as a current distributor. In any form, each layer can be represented by a very thin, highly flexible metal mesh. This can be a fine, as opposed to a coarse, mesh which has extremely thin strands and small voids. The electrode will have an active coating. For utilizing this electrode, the cell in one form will be a monopolar cell providing upward, parallel electrolyte flow through the porous, multi-layered electrode. A representative cell can have such electrode at least substantially filling an electrode chamber. The cells can be contained in a cell box that will provide the desired flow-through relationship for the electrolyte to the electrode.

Abstract: An electrode, electrochemical cell, and electrochemical processes are disclosed. The electrode is a porous, multi-layered electrode which can have an element in flexible, strip form wound around a central, usually flat plate core, which core may serve as a current distributor. In any form, each layer can be represented by a very thin, highly flexible metal mesh. This can be a fine, as opposed to a coarse, mesh which has extremely thin strands and small voids. The electrode will have an active coating. For utilizing this electrode, the cell in one form will be a monopolar cell providing upward, parallel electrolyte flow through the porous, multi-layered electrode. A representative cell can have such electrode at least substantially filling an electrode chamber. The cells can be contained in a cell box that will provide the desired flow-through relationship for the electrolyte to the electrode.

Abstract: A method of preparing electrodes is now described, which electrodes have enhanced adhesion of subsequently applied coatings combined with excellent coating service life. In the method, a substrate metal, such as a valve metal as represented by titanium, is provided with a highly desirable rough surface characteristic for subsequent coating application. This can be achieved by various operations including etching to ensure a roughened surface morphology. In subsequent operations, a barrier layer is provided on the surface of enhanced morphology. This may be achieved by operations including heating, as well as including thermal decomposition of a layer precursor. Subsequent coatings provide enhanced lifetime even in the most rugged commercial environments.

Abstract: A method of preparing electrodes is now described, which electrodes have enhanced adhesion of subsequently applied coatings combined with excellent coating service life. In the method a substrate metal, such as a valve metal as represented by titanium, is provided with a highly desirable rough surface characteristic for subsequent coating application. This can be achieved by various operations including etching and melt spray application of metal or ceramic oxide to ensure a roughened surface morphology. In subsequent operations: a barrier layer is provided on the surface of enhanced morphology. This may be achieved by operations including heating, as well as including thermal decomposition of a layer precursor. Subsequent coatings provide enhanced lifetime even in the most rugged commercial environments.

Abstract: A metal surface is now described having enhanced adhesion of subsequently applied coatings. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable surface characteristic for subsequent coating application. This can be initiated by selection of a metal of desirable metallurgy and heat history, including prior heat treatment to provide surface grain boundaries which may be most readily etched. In subsequent etching operation, the surface is made to exhibit well defined, three dimensional grains with deep grain boundaries. Subsequently applied coatings, by penetrating into the etched intergranular valleys, are desirably locked onto the metal substrate surface and provide enhanced lifetime even in rugged commercial environments.

Abstract: A metal surface, useful as an electrode in an electrolytic cell, is now described having enhanced adhesion of subsequently applied coatings combined with excellent coating service life. The substrate metal of the electrode, such as a valve metal as represented by titanium, is provided with a highly desirable rough surface characteristic for subsequent coating application. This can be achieved by various operations including etching and melt spray application of metal or ceramic oxide to ensure a roughened surface morphology. Usually in subsequent operations, a barrier layer is provided on the surface of enhanced morphology. This may be achieved by operations including heating, as well as including thermal decomposition of a layer precursor. Subsequent coatings provide enhanced lifetime even in the most rugged commercial environments.

Abstract: A metal surface is now described having enhanced adhesion of subsequently applied coatings. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable surface characteristic for subsequent coating application. This can be initiated by selection of a metal of desirable metallurgy and heat history, including prior heat treatment to provide surface grain boundaries which may be most readily etched. In subsequent etching operation, the surface is made to exhibit well defined, three dimensional grains with deep grain boundaries. Subsequently applied coatings, by penetrating into the etched intergranular valleys, are desirably locked onto the metal substrate surface and provide enhanced lifetime even in rugged commercial environments.

Abstract: A metal surface is now described having enhanced adhesion of subsequently applied coatings. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable surface characteristic for subsequent coating application. This can be achieved by a plasma sprayed coating of well defined surface morphology, the plasma spraying being with one or more metals usually valve metals. The metal of the coating may be the same or different from the metal of the substrate. Subsequently applied coatings, by penetrating into the coating of well defined surface morphology, and desirably locked onto the resulting metal article an provide enhanced lifetime even in rugged commercial environments.

Abstract: A metal surface is now described having enhanced adhesion of subsequently applied coatings combined with excellent coating service life. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable rough surface characteristic for subsequent coating application. This can be achieved by various operations including etching and melt spray application of metal or ceramic oxide to ensure a roughened surface morphology. Usually in subsequent operations, a barrier layer is provided on the surface of enhanced morphology. This may be achieved by operations including heating, as well as including thermal decomposition of a layer precursor. Subsequent coatings provide enhanced lifetime even in the most rugged commercial environments.

Abstract: A metal surface is now described having enhanced adhesion of subsequently applied coatings. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable surface characteristic for subsequent coating application. This can be initiated by selection of a metal of desirable metallurgy and heat history, including prior heat treatment to provide surface grain boundaries which may be most readily etched. In subsequent etching operation, the surface is made to exhibit well defined, three dimensional grains with deep grain boundaries. Subsequently applied coatings, by penetrating into the etched intergranular valleys, are desirably locked onto the metal substrate surface and provide enhanced lifetime even in rugged commercial environments.

Abstract: A coating is now disclosed which is especially serviceable as an improved electrocatalytic coating for an electrode. The coating is a crystalline coating of mixed oxides. The oxides are of iridium, ruthenium and titanium, in very specially defined proportions. When the coating is present on an electrically conductive metal substrate that can serve as an electrode, such electrode has, in combination, the characteristics of reduced oxygen evolution in a membrane cell, low chlorine electrode potentials, plus reduced coating weight loss in a caustic environment.

Abstract: A metal surface is now described having enhanced adhesion of subsequently applied coatings. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable surface characteristic for subsequent coating application. This can be initiated by selection of a metal of desirable metallurgy and heat history, including prior heat treatment to provide surface grain boundaries which may be most readily etched. In subsequent etching operation, the surface is made to exhibit well defined, three dimensional grains with deep grain boundaries. Subsequently applied coatings, by penetrating into the etched intergranular valleys, are desirably locked onto the metal substrate surface and provide enhanced lifetime even in rugged commercial environments.

Abstract: A method is now utilized for stripping costly electrocatalytic coatings from valve metal substrates while maintaining excellent integrity of the substrate metal. The removed metal may also be conveniently recovered. A molten salt bath of alkali metal hydroxide and alkali metal salt of an oxidizing agent is employed. Careful electrode to bath contact times and bath temperatures are observed. Additionally, a dilute mineral acid rinse and water rinse, with scrubbing in one of the rinses follows such molten salt bath contact for the electrode. Solids recovered from the rinses are combined.

Abstract: Chlorine dioxide is generated from chlorate salt and introduced into a treatment stream. Initially following dissolution of the salt in aqueous medium, the solution is subjected to ion exchange for producing intermediate chloric acid. The acid is next converted to chlorine dioxide by electrolysis. The chlorine dioxide produced can then be extracted for use with a treatment stream. The chlorine dioxide generated can be free from unwanted by-products. The total generation system lends itself to recycling of unused product for obtaining virtually complete conversion of chlorate salt to useful chlorine dioxide.

Abstract: A heterogeneous catalyst and method for making chlorine dioxide from an acid and a metal chlorate solution. The catalyst comprises coformed mixed oxides of platinum group metals with at least one valve metal oxide.