Abstract: A chromium regeneration apparatus (10) is disclosed for regenerating spent chromium solution by oxidizing trivalent chromium to hexavalent chromium. The apparatus is provided with a tank (42) forming a reservoir full of spent chromium solution. A number of anode assembles (46) are supported on the tank within the reservoir with each assembly including two frame sections (70, 72) bolted together along their sides and bottom with two separate cation selective membranes (100, 102) secured therebetween. Membrane tensioners (104) are inserted between the membranes to separate them and urge them against the frame sections over openings in the frame sections to define an anode chamber. An anode and cathode are provided to a generate a current flow therebetween to regenerate the solution.

Abstract: In an electrode assembly for gas-forming electrolyzers, particularly for monopolar membrane electrolyzers comprising vertical plate electrodes and opposite electrodes and a membrane between the plate electrode and the opposite electrode, the distribution of current in the membrane is improved and the voltage drop is decreased in that the plate electrodes are provided on that surface which faces the membrane with ante-electrodes, which consist of apertured, electrically conducting surface structures, which are electrically conductively connected to the plate electrodes and extend in planes which are parallel to the plate electrodes.

Abstract: A membrane electrode device used as one electrode provided in association with an article to be coated such as a motor vehicle constituting the other electrode in electrodeposition coating widely used in automatic coating film treatment and the like of motor vehicle bodies. This device includes a tubular support membrane support member formed of mesh-like skeleton members, a membrane wound around the outer periphery of this membrane support member, and an electrode provided at the side of the inner surface of the membrane support member at a given interval therefrom. Part of portions of the skeleton members, which are provided in the vertical direction, are raised to some degree outwardly from the other skeleton portions.

Abstract: A process for fabricating a unitary membrane-electrode structure by attaching an electrode to a permselective membrane while the latter is in a non-hydrated (and essentially non-dissociated) form. The electrode, in the form of a bonded aggregate of catalytic and polymeric binder particles, is attached to a membrane having less than 0.01 grams of matrix water per gram of dry membrane by the application of heat and pressure. The membrane is then hydrated causing the membrane to swell by a controlled amount and converting it to the dissociated form. A membrane-electrode structure fabricated in this manner is particularly useful in the electrolysis of alkali metal halides because it is characterized by improved cathodic current efficiency and by reduced susceptibility to permeation of gaseous hydrogen.

Abstract: An alkali metal salt solution is electrolyzed in an electrolytic cell with at least two electrode compartments adapted to being separated by a membrane. At least one electrode compartment contains at least one means defining a space adapted to receive a portion of membrane surface during operation of the cell. By maintaining the pressure higher in one electrode compartment than the other the membrane portion is pushed toward and into the membrane receiving space such that any wrinkles formed on the membrane are removed.

Abstract: Disclosed herein are processes for preparing a raw material dispersion and raw material powders for producing reaction layers of a gas permeable electrode. The raw materials are prepared in one aspect of the invention by mixing fine particles containing a surface-active agent, freezing the mixture to a temperature at which the surface-active agent loses at least part of its function and then thawing out the same. The resulting material exhibits superior catalytic performance because the particles are dispersed uniformly by the lack of function of the surface-active agent at the time of freezing.The raw materials are prepared in another aspect of the invention by mixing hydrophilic minute particles coated with an ion exchange resin, PTFE and hydrophobic fine powders.

Abstract: Solid compositions based on superoxides comprise a material inert with respect to O.sub.2 - anions playing the role of matrix with regard to these anions, and O.sub.2 - anions, these compositions forming a material stable up to about 100.degree. C. This matrix permits the mobility of the O.sub.2 - anions in this temperature region. These compositions are usable as electrolytes (1) in an electrochemical cell.

Abstract: Gas diffusion electrodes, gas generating or consuming electrochemical cells utilizing such electrodes, and a method of preparing such electrodes are disclosed. The electrode comprises an electronically conductive porous body defining respective gas and electrolyte contacting surfaces. The electrode is prepared by forming the porous body, disposing the electrolyte contacting surface in contact with an electrolyte, and contacting the gas contacting surface with a gaseous atmosphere. Current is passed through the porous body at a degree of electrode polarization much higher than normal whereby modification of the electrode material is effected. If desired, a catalyst may be incorporated in the electrode and is subjected to pretreatment as well. The inventive electrodes exhibit superior voltage performance under oxygen polarization conditions.

Abstract: An electrolyzer for alkaline electrolysis of water has a diaphragm-electr sandwich arrangement wherein a predetermined narrow spacing to provide a minimum distance is maintained between the diaphragm surface and the superjacent electrode. The spacing is provided by a single layer of a filament of predetermined thickness disposed in an array. The filament is strung in a plurality of lengths disposed in a common plane so that the thickness of the spacing is the same as the thickness of the single layer which is equal to the filament thickness. The array is secured by a retaining wire which engages a groove provided in a cell frame of the electrolyzer. The filament is made of plastic material which can withstand electrolysis conditions. An apparatus and method for stringing the filament to provide the array are also described.

Abstract: A halogen, such as chlorine, is generated by electrolysis of an aqueous solution of an alkali metal halide such as sodium chloride, in a cell having anolyte and catholyte chambers separated by a solid polymer electrolyte in the form of a stable, selectively cation permeable, ion exchange membrane. One or more catalytic electrodes including at least one thermally stablized, reduced oxide of a platinum group metal are bonded to the surface of the membrane. An aqueous brine solution is brought into contact with the anode and water or an aqueous NaOH solution is brought into contact with the cathode. The brine is electrolyzed to produce chlorine at the anode and hydrogen and caustic at the cathode. The cell membrane preferably has an anion rejecting cathode side barrier layer which rejects hydroxyl ions to block back migration of caustic to the anode thereby enhancing the cathode current efficiency of the cell and of the process.

Abstract: The invention is a membrane/electrode combination having an electrically conductive screen which has a first and a second face. The first face is substantially flat and the screen has a plurality of openings passing through it. The openings connect the first and the second faces of the screen and occupy up to about 75% of the surface area of each face of the electrically conductive screen. There is also an ion exchange membrane film having a first and a second face. The first face of the membrane film is attached to the first face of the electrically conductive screen, thereby leaving portions of the first face of the membrane film exposed through the openings in the electrically conductive screen. A plurality of catalytically active particles are disposed on the exposed portions of the first face of the membrane film and are in electrical and physical contact with the membrane and with the electrically conductive screen.

Abstract: Bonded, coherent fibrous web substrates well adopted as cathodic elements for electrolytic cells and advantageously incorporating an electrocatalytic agent, include a web matrix which comprises a plurality of fibers, at least a portion of which comprising electrically conductive fibers, e.g., carbon fibers, said plurality of fibers being coherently bonded together with a fluorine-containing polymer, and said web substrate having a resistivity of up to about 0.4 .OMEGA..cm.

Abstract: Monopolar, bipolar, and hybrid filter press electrolytic cells for electrolytic processes utilizing a novel method of introducing and removing electrical energy are disclosed. The invention contemplates a novel low pressure, high surface contact area connecting means for joining the anode element and cathode element of electrode assemblies. The invention also contemplates a low pressure, high surface contact area contact of the current distributor member to the back plate.

Abstract: The invention is a method for making an improved membrane/electrode combination by at least partially coating at least a portion of a first face of a screen template with a plurality of catalytically active particles, where the substantially flat screen has the first face, a second face, and a plurality of openings passing therethrough which connect the first and the second faces of the screen. The openings occupy up to about 75% of the surface area of each face of the screen template. The coated face of the screen template is contacted with an ion exchange membrane. The catalytically active particles are transferred from the screen template to the membrane and the particles are bonded to the membrane.

Abstract: An inorganic gas separator which has a porosity between 30 and 70% and a pore diameter between 10 and 100 .mu.m, and which is gas impermeable when soaked-through with liquid, is mounted in a frame, divides a cell housing into two compartments, and is moistened by capillarity with liquid fed through channels extending in the frame. In each compartment are mounted a porous foil, an electrode, a pre-electrode, a metal plate and an insulating plate. On the cell-housing thermo-electric heat pumps are mounted for cooling and the unit formed by the housing and the pumps is surrounded by an outer casing.

Abstract: A diaphragm-electrode system for electrocoating including an electrode provided as a counterpart electrode corresponding to a substrate that functions as an electrode on one side, and a diaphragm that serves to separate the counterpart electrode from the foregoing substrate acting as the electrode opposing to the former, as well as from the paint components in aqueous solution for electrodeposition. The diaphragm is disposed in a form to encircle the outer surface of a diaphragm backing member. The diaphragm backing member is tubular in form and made of insulating material having a water permeating structure. The counterpart electrode is encased inside of the diaphragm backing member. Between the counterpart electrode and the diaphragm backing member, a water running mechanism is provided in order to forcibly flow water from one side along a direction to the other side.

Abstract: An electrode for membrane electrolysis comprises an electrode body, whose surface is provided at least partially with an electro-catalytically active coating.The electrode body is constructed from a plurality of parallel, mutually spaced lamellas having a plurality of recesses on edge surfaces facing the membrane, edge surfaces of bridge portions, located between these recesses, not being coated for electro-catalytic activity.

Abstract: An electrolysis unit for improving water quality in continuous production comprises a pair of electrodes formed into cylinders and an ion-exchanging membrane disposed between the cylinders so as to form two separate water paths having circular forms with thin widths. The membrane is characterized by special supporting structure therefor to maintain its shape.

Abstract: A method of improving performance in an electrochemical cell having a consumable metal anode defining an anode face and a cathode spaced from the anode face and defining an electrolyte flow channel therebetween whereby an aqueous alkaline electrolyte flows through a system of flow baffles disposed in the electrolyte flow channel of the cell. The flow baffles define an electrolyte flow path having a directional vector component perpendicular to a sufficient component of a flow vector of the electrolyte to increase the speed at which the electrolyte passes across the anode face at any selected volumetric flow rate as compared to an otherwise identical cell without such baffles.

Abstract: An electrolyzer for the production of chlorine from an aqueous alkaline halide solution includes a plurality of electrolysis cells each having a housing of two half-shells. The bottom side of each of the half-shells is in a plane parallel to a plane of an adjacent anode or cathode, the space between the bottom side and the anode or the cathode being provided with framework-pattern metallic reinforcements. Each bottom side has one or more contact strips attached to its outer surface which are arranged in a congruent position to the contact strips on the bottom side of the adjacent electrolysis cell, and extend over the length or width of the cell. The contact strips are aligned with and connected by electrically conducting means to part of the framework-pattern reinforcements and the unperforated sections of the adjacent anode or cathode. The two half-shells and a membrane partition wall are assembled to form an electrolysis cell sealed by two gaskets.

Abstract: A blend of fluorocarbon polymers for incorporation into an asbestos fiber slurry for forming into a diaphragm is disclosed. The blend comprises fluorocarbon polymer fibers and fluorocarbon polymer chunks of certain sizes in certain weight ratios. Also disclosed is a diaphragm comprised of the asbestos and two types of fluorocarbon polymers, as well as a method of making same.

Abstract: An improved arrangement of electrochemical cells wherein the individual cells are arranged on a single electrolytic membrane. The arrangement provides for the placement of many individual cells in one chamber, thereby eliminating the many chamber walls and inlet and outlet lines associated with the standard structure. An electrochemical device can thus be constructed very simply and, when the cells are electrically connected in series, will operate at voltages compatible with standard battery voltages or generate power at any desired voltage.

Abstract: A continuous flow electrophoretic separator (10) is provided, comprising a cylindrical stator (12) and a concentric tubular rotor (14), and electrode systems (24, 26) incorporated into the stator and the rotor defining between them an annular separation chamber (28). One or both electrode systems include a tubular semi-permeable membrane (56) supported by a support tube (58) of a rigid plastics material and grooved on its inner and outer surfaces. The grooves (64, 62) are deep enough to provide fluid communication between the two surfaces of the support tube, and those grooves (64) adjacent to the separation chamber are preferably less than 3 mm wide. If the membrane (56) is between the support tube (58) and the separation chamber (28), then the support tube (58) may have both longitudinal (60) and circumferential grooves (64) adjacent the membrane, and longitudinal grooves (62) on its other surface.

Abstract: A multi-layered diaphragm for electrolysis, which comprises a porous layer of a fluorine-containing polymer having a pore diameter of from 0.05 to 10 .mu.m, a porosity of from 30 to 95% and a thickness of from 30 to 450 .mu.m and with its interior and anode-side surface being hydrophilic, and an ion exchange resin layer supported on the cathode side thereof and having a thickness thinner than the porous layer but of at least 5 .mu.m and an ion exchange capacity of from 0.5 to 2.0 meq/g dry resin, the total thickness being from 35 to 500 .mu.m.

Abstract: There is disclosed a composite membrane and an air electrode for use in hydrogen-oxygen fuel cells, metal-air cells and oxygen sensors. The composite membrane includes a porous membrane having micropores with a thin layer affixed thereto. The thin layer having metallic oxide in a carbon matrix, so that oxygen gas is able to permeate therethrough, but water vapor in air is not allowed to permeate therethrough.

Abstract: An electrochemical extraction method comprises establishing a cell of the form working electrode: flowing aqueous electrolyte solution: second electrode. The working electrode includes an ion exchange material and the second electrode may include ion exchange material. D.C. potential is applied to the cell to adsorb ions onto the working electrode and cell polarity is subsequently reversed to elute the adsorbed ions.The cell is separated by a cell divider, e.g. in the form of an ion selective membrane, into first and second electrolyte compartments and the solution is passed through the compartment adjacent the working electrode to effect adsorption and, where the second electrode includes ion exchange material, solution is passed through the compartment adjacent the second electrode to effect desorption.

Abstract: A continuous electrolytic generator is disclosed having two sealed compartments, separated by a cation exchange membrane, having a cathode in one compartment, and an anode in the other. A bipolar electrode is positioned in the anode compartment between the cation exchange membrane and the anode. The bipolar electrode may be supported on the dividing wall spaced from the ion-exchange membrane. The bipolar membrane may also be supported on the anode on insulators in spaced relation thereto. The generator has exterior reservoirs for continuously circulating solutions to and from the anode and cathode compartments. A third reservoir receives make-up water and salt and is connected to supply brine to the exterior anode reservoir. The cell produces a mixture of oxidant gases containing chlorine, chlorine dioxide, oxygen, hydrogen peroxide, and possibly ozone, from the anode compartment which is connected to a gas collection and utilization system, e.g., a venturi in a flowing water line.

Abstract: Electrolysis cell incorporating, in an enclosure, electrodes (17) each of which passes, in a leaktight manner, through an individual opening (16) in a wall (4) of the enclosure and each of which is surrounded by an individual bag-shaped tubular separator (20) engaged in a leaktight manner in the abovementioned opening in the wall.

Abstract: Unitary, cast structural element for filter press electrolysis cell which incorporates into a single unit the central barrier between the peripheral boundaries for the adjacent anode compartment and adjacent cathode compartment of two electrolysis cells located on opposite sides of the central barrier. Also incorporated into the single cast structural element are anode component bosses and cathode component bosses extending outwardly from opposite sides of the central barrier. These bosses not only serve as mechanical support for their respective flat plate anode component and cathode component, but also they serve as stand-off means and electrical current collectors and dispersers from the cathode component of one electrolysis cell to the anode component of the next cell. Simplicity of design coupled with incorporation of many functional elements into one part eliminates many cell warpage problems, inherent high voltage problems and membrane "hot spot" problems.

Abstract: The invention relates to an ion exchange-type electrolytic cell with electrodes retained in close proximity to each other by means of a spring element.

Abstract: A reinforced ion exchange membrane which comprises fluorinated polymer which has carboxylic functional groups, which has a hydrogen bubble release layer on the cathode-facing side thereof, and which has channels open to the outer surface of the anode-facing side thereof, is described. Precursor membrane, which may contain partially embedded sacrificial members, and from which the reinforced ion exchange membrane is made, is also described. The reinforced ion exchange membrane can be used to separate the compartments of a chloralkali cell, and such a cell operates at low voltage, high current efficiency, and low power consumption.

Abstract: An electrically conductive layer on a solid-body electrolyte (1) is produced by swelling and impregnating an organic ion exchange material (2) with a metal salt solution, drying, converting the metal ions in a gas stream to finely distributed particles (3) which are in electrical contact with one another, renewed swelling in a solvent, converting into a brushable paste and applying same to the surface of the solid-body electrolyte and drying. Preferred embodiment: solid-body electrolyte (1) and ion exchange material (2) made of polymers containing sulphonic acids; and conductive particles (3) made of platinum metals or oxides thereof, in particular ruthenium as electrocatalyst.

Abstract: An electrolytic cell comprising a plurality of anodes and a plurality of cathodes, and a hydraulically impermeable cation-exchange membrane and a gasket of an electrically insulating material positioned between each adjacent anode and cathode to form in the cell a plurality of separate anode and cathode compartments, in which either(a) the cation-exchange membrane is in contact with the anode at least around the periphery of the anode and the gasket is positioned between the membrane and the cathode and abuts onto that part of the membrane which is in contact with the periphery of the anode, or(b) the cation-exchange membrane is in contact with the cathode at least around the periphery of the cathode and the gasket is positioned between the membrane and the anode and abuts onto that part of the membrane which is in contact with the periphery of the cathode.

Abstract: Shunt currents which flow between the electrodes of adjacent cells through the moving conductive fluid and the fluid pool in the manifold of a bipolar cell assembly are minimized by introducing the conductive fluid at the top of an elongated outlet manifold. This results in cascaded flow which interrupts the current path. Shunt currents between the fluid manifold walls of the conductive bipolar elements in the series connected electrochemical cell assemblies are minimized by insulating the manifold walls with insulating, elastomeric sealing grommets. This prevents current flow between the manifold walls through the electrically conductive fluid in the manifold and provides an edgeseal between bipolar plates.The instant invention relates to a process and apparatus for electrochemical cell assemblies and more particularly, for reducing shunt current in series connected bipolar assemblies.

Abstract: An electrolytic cell comprises an anode and a cathode which are partitioned by an ion exchange membrane having at least one roughened surface which contacts with or closes in a distance of up to 20 mm to a corresponding electrode.

Abstract: An electrode, especially for chlorine and hypochlorite production, comprises an electrocatalyst consisting of 22-55 mol % ruthenium oxide, 0.2-22 mol % palladium oxide and 44-77.8 mol % titanium oxide. The electrocatalyst may form a coating on a valve metal substrate and may be topcoated with a porous layer of titanium or tantalum oxide.

Abstract: In an electrolytic cell having a membrane and vertical electrodes composed of a plurality of units,a. the electrode having one polarity is horizontally divided into a plurality of units,b. the electrode having the opposite polarity is vertically divided into a plurality of units, andc. the units of at least one of the two electrodes are adapted to be displaced by spring elements. Spacers are suitably provided between the units of that electrode which is not contacted by the membrane.

Abstract: An electrolytic cell, and a gasket therefor, the cell comprising at least one anode and at least one cathode and a separator positioned between an anode and adjacent cathode and dividing the cell into separate anode and cathode compartments, the gasket comprising a plurality of projections and recesses on or in a surface thereof, and preferably on or in both surfaces thereof, adapted to cooperate with corresponding recesses and projections in or on a surface of an anode or cathode or a gasket adjacent thereto.

Abstract: The integrated electrochemical/chemical oxygen generating system of the invention includes a water electrolyzer combined with a chemical oxygen generating subsystem which converts hydrogen from the electrolyzer to a decomposable oxygen source such as hydrogen peroxide. The total oxygen output of such a system is greater than that possible from the electrolyzer alone while safely disposing of the electrochemically generated hydrogen.

Abstract: An electrochemical cell having dished electrodes received in rectangular frame members, and arranged to form a bipolar stack. Electrolyte inlets and outlets open into plenum chambers defined between the dished electrodes and the frame members. A turbulence promoter substantially fills the flowpath between the electrolyte inlet and electrolyte outlet.

Abstract: The invention relates to a membrane electrolysis cell of the filter press type with one or more plate-type electrode pairs, each comprising at least one non-continuous active central part, with a membrane provided between the electrode pairs, and with a seal installed between each electrode and membrane rim. The membrane cell is suitable for the production of an aqueous alkali metal hydroxide solution (cell liquor) as well as of halogen and hydrogen by electrolyzing an aqueous halide-bearing electrolyte (brine).The non-continuous central part of the electrodes has a grid-type structure, the grid rods of the electrode pairs are staggered by a maximum of half the rod width, the grid rods of the electrodes are arranged so that their interspace is smaller than the projection of their width, the grid rods have a convex face at least on the active side, and the thickness of the seals between the electrode and membrane rims is equal or inferior to the height of the grid rod portion protruding over the electrode rim.

Abstract: A method for making polymer bonded electrode (PBE) structures wherein the particulate and particles of perfluorocarbon copolymer are combined with a solvent for the copolymer at a temperature where significant solvation of the perfluorocarbon does not occur. The resulting blended dispersion is spread to form the PBE, and the solvent removed. The PBE is then fused under heat and pressure for use.

Abstract: Disclosed is a permionic membrane having a porous film of surface and electrocatalyst on at least one surface thereof. Also disclosed is an electrolytic cell with the permionic membrane, an electrolytic process utilizing the permionic membrane, and an electrolytic process utilizing the electrolytic cell.

Abstract: A novel, electrocatalytic material comprising at least one reduced platinum group metal oxide is subsequently heated in the presence of oxygen at a temperature high enough to stabilize the catalyst in acidic and halogen environments. The catalyst optionally contains other thermally stabilized, reduced platinum group metal oxides, electroconductive extenders of the group consisting of graphite and oxides of transition or valve metals. A novel electrode structure includes the catalyst and a polymeric binder. A novel method of preparing the electrocatalytic material is described as well as a unitary electrolyte electrode structure which has a bonded electrode containing the novel electrocatalytic material, bonded to at least one side of a membrane-electrolyte.

Abstract: An electrode frame for the electrolytic recovery or purification of metals comprises four frame arms (1-4). It serves to tension a filter cloth arranged on both sides of the frame plane between which the interior (5) of the frame is enclosed. In order to keep constant the tension of the filter cloths, at least one (4) of the arms (1-4) is flanked by a pressure bar (6) which extends essentially parallel thereto, is spaced therefrom and is charged with spring pressure in a direction (7) leading away from the frame interior (5).

Abstract: An electrolyzer is provided which includes at least one set of closely spaced electrode assemblies consisting of a flat anode and a flat cathode separated by a membrane permeable to ions. One side of the electrode assembly is supported by a rigid pressure plate while a flexible pressure plate disposed along the opposite side of the electrode assembly biased the anode and cathode towards each other. The flexible pressure plate includes a flat portion having contact pads struck and formed therefrom. The contact pads are sized to cover from 30 to 70% of the overall plate surface and include portions which are plane-parallel to the flat portion. The contact pads bent to one side are designed to be vertical on a longitudinal axis after mounting of the flexible pressure plate in an electrolyzer.

Abstract: The economy of production of hydrogen and sulfuric acid in a three chamber lectrolysis cell in which an electrolyte flows through the intermediate chamber (11) which is bounded by ion exchanger membranes (9,10) can be improved by the provision of a porus supporting framework or skeleton (12) of graphite or of ion exchanger material against which the separators with the electrodes (7, 8) on them, can be pressed. The overall internal resistance of the cell can thus be reduced and its mechanical behavior improved. Substantial through passage porosity is desired in the supporting structure, which may be of graphite, but porous aggregates of ion exchanger material with fixedly applied or welded on separators in the form of stacked layers or rolled mats, are preferred for the relative simplicity of their provision in practice.

Abstract: A solid polymer electrolyte (SPE), solid polymer electrolyte electrode, and method for forming from cationic exchange perfluorocarbon copolymer. Disclosed are solution techniques for forming SPEs and SPE electrodes using fluorocarbon vinyl ether copolymers.

Abstract: An electrolytic chlorine generator employing a porous ceramic diaphragm for the separation of the caustic soda solution from the weakly acidic brine solution and employing as the cathode a flame or plasma deposited porous metallic coating on the outer surface of the ceramic diaphragm.

Abstract: A cell for the electrolysis of magnesium at low temperatures and electrical potential using a composite anode consisting of a mixture of an oxygen containing compound of magnesium and a reducing agent with internal conductors extending through the composite mixture to provide low resistance current paths through the highly resistive mixture to the active anode surface. The mixture may be employed in a self-baking mode or be prebaked. Alternatively, the mixture may be in particulate form contained within a porous membrane. A bipolar arrangement may also be employed.