Abstract: A process for electrolysis of an electrolyte, e.g. aqueous alkali metal chloride solution in an electrolytic cell comprising a plurality of anodes and cathodes and separators positioned between adjacent anodes and cathodes to form in the cell a plurality of anode compartments and cathode compartment, the process comprising charging the electrolyte to the anode compartments, electrolyzing the electrolyte, and removing the products of electrolysis from the anode and cathode compartments, the anodes and cathodes comprising an electroconducting electrocatalytically-active portion affixed to a frame member of an electrically non-conducting plastics material, and the frame members being bonded directly or indirectly to each other. Also an electrolytic cell for use in the process.

Abstract: There are provided integrated modules for use in electrodialysis devices, which modules comprise a plurality of unit cells each of which consists of a cation specific membrane, a spacer and an anion specific membrane, said membranes being sealed along the edges of the cell, a spacer being provided between consecutive cells serving for sealing along the edges, an outlet being provided for the brine, outlets of individual cells being arranged as common outlet, a plurality of unit cells being confined in a frame which is provided with an outlet for said cells, each frame being provided with sealing means towards the next such frame. There are also provided electrodialysis stacks comprising a plurality of such modules.

Abstract: An apparatus for recovering metals, such as gold and silver, dissolved in a solution, such as plating waste, rapidly and effectively, comprising a collector (electrolyzing device) for depositing metals in a solution on conductive particles, and a plating device (electrolysis recovering device) for recovering the metals in the form of plating.

Abstract: A system to generate chlorine to disinfect a body of water. The system has a pump to move water through the system, a filter and an electrolytic cell able to generate chlorine by the electrolysis of sodium chloride and having an anode and a cathode mounted in a separate compartment. Chlorine is generated in the anode compartment and hydrogen in the cathode compartment. The compartments are in communication through an ion permeable membrane. There is a power source for the cell. The ion permeable membrane is formed as separate members, each covering an opening in a wall dividing the anode and cathode compartments. The anode and the cathode are located above the electrolyte. There is a mixing container divided into compartments, a first compartment to receive hydrogen and chlorine from the cell and provided with an outlet for water and the second compartment, in communication with the first and having an inlet for water, a float valve to control the inlet, the mixing container having a pressure relief outlet.

Abstract: An improved process for the electrolysis of an aqueous electrolyte in an electrolytic membrane cell is provided. The membrane cell is comprised of an anode compartment having at least one anode and containing the aqueous electrolyte and a cathode compartment containing at least one cathode and a concentrated catholyte liquor. A vertically positioned cation exchange membrane separates the anode compartment from the cathode compartment. The process improvement comprises exposing a substantial portion of the cathode to a gaseous atmosphere, this substantial portion of the cathode is not immersed in the concentrated catholyte liquor produced. The concentrated aqueous catholyte liquor is removed from the cathode compartment to prevent a substantial accumulation of catholyte liquor in the cathode compartment.

Abstract: A divided electrochemical cell assembly comprises stacked bipolar substantially square parallel planar electrodes and membranes. The corners and edges of the electrodes with bordering insulative spacers in juxtaposition with the chamber walls define four electrolyte circulation manifolds. Anolyte and catholyte channeling means permit the separate introduction of anolyte and catholyte into two of the manifolds and the withdrawal of anolyte and catholyte separately from at least two other manifolds. The electrodes and membranes are separated from one another by the insulative spacers which are also channeling means disposed to provide electrolyte channels across the interfaces of adjacent electrodes and membranes.

Abstract: An electrolytic cell of the filter press type comprising a plurality of anodes and cathodes arranged in an alternating manner,a separator positioned between each adjacent anode and cathode to form in the cell a plurality of anode and cathode compartments, anda header for electrolyte which header is connected by means of passageways to each of the anode compartments of the electrolytic cell,in which each passageway comprises a device which is so shaped that in use it creates a vortex flow in the electrolyte flowing from the header to the anode compartments of the cell.

Abstract: Disclosed is a method of replacing a structurally damaged membrane after determining which membrane in a multiple unit filter press membrane electrolytic cell is damaged in response to cell operating conditions and monitorings indicating a problem exists.

Abstract: A bipolar electrolytic cell has a plurality of unit cells electrically aligned in series, each of the unit cells being divided into an anode chamber and a cathode chamber by an ion-exchange membrane, and each of the anode and cathode chambers having a supply pipe and a discharge pipe which are respectively connected at one end to common headers. The other end of each of the supply or discharge pipes in the anode or cathode chambers is inserted deep into the respective electrode chamber so that at least 50% of the electrical resistance of the liquid in each pipe exists in the electrode chamber, and the wall of the inserted portion of each pipe electrically insulates the liquid in the pipe from a liquid in the electrode chamber.

Abstract: An electrode, suitable for use in an electrolytic cell of the filter-press type, and comprising a substantially planar support member and on at least one face of the support member, and preferably on both faces, a plurality of elongated members, for example strips, substantially parallel to each other and each attached at both ends to the support member, a substantial part of the elongated members lying in a plane displaced from and substantially parallel to the support member and the faces of the elongated members lying in planes substantially parallel to the plane of the support member. Also an electrolytic cell, incorporating the electrode.

Abstract: A novel commercial chlor-alkali electrolytic cell which has a pack of less than about 50 interleaved parallel planar electrode frames and substantially horizontal conductor rods. The pack is at least half and preferably twice as tall as it is thick.

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: A monopolar membrane electrolytic cell is comprised of a plurality of anodes wherein each anode is comprised of a first foraminous surface and a second foraminous surface positioned in parallel and spaced apart, and a frame enclosing the first and the second foraminous surfaces. The frame has two side members, a top member, and a bottom member attached to the foraminous surfaces. A chamber is formed between the foraminous surfaces and bounded by the frame. Conductor rods pass through one of the side members of the frame into the chamber, the conductor rods being spaced apart from the foraminous surfaces. Foraminous conductive connectors are positioned in the chamber and attached to the conductor rods and to the foraminous surfaces; a plurality of cathodes wherein each cathode is comprised of at least one foraminous surface, and a frame which encloses the foraminous surface.

Abstract: Chlorine dioxide is produced by electrolysis of a solution of chlorite and by using a compact apparatus which provides continuously a uniform concentration of chlorine dioxide, which can be operated easily, which discharges a spent electrolyte that can be treated easily and which achieves highly efficient use of chlorite and high current efficiency.

Abstract: An electrolyzer for producing an aqueous alkali hydroxide solution, halogen, and hydrogen from an aqueous halogenide-bearing electrolyte. The electrolyzer includes a plurality of alternating anolyte and catholyte chambers each formed by a pair of anode plates and cathode plates, respectively. Seals are provided between and around the perimeter of the two anode and cathode plates to define the chambers. A flat membrane member, permeable to ions is disposed between adjacent anode and cathode plates. The anode and cathode plate and seals include passages for the flow of process fluids. Each anode and cathode plate comprises an active portion permeable to the flow of gas and liquid and an inactive portion impermeable to the flow of gas and liquid.

Abstract: Disclosed is a method of determining which membrane in a multiple unit filter press membrane electrolytic cell is structurally damaged after cell operating conditions and monitorings indicate the problem exists.

Abstract: A method for assembling a filter press type of electrolytic cell is disclosed wherein tightening apparatus is employed at preferably multiple points about the periphery of the stacked electrodes to substantially simultaneously apply a substantially uniform pressure to compress the cell to permit the compressed stack of electrodes to be retained in this compressed state while the cell is assembled in a fluid-tight manner.

Abstract: The product is in the form of discrete particles or in the form of a layer comprising an electrode. It consists of a semi-conductor material subject to photo-corrosion, for example, cadmium sulphide. In order to prevent such photo-corrosion, the surface of the semi-conductor material, which is intended to be illuminated, is covered with a transparent layer of RuO.sub.2, IrO.sub.2 or a mixture of RuO.sub.2 and IrO.sub.2.The product may be used for the conversion of solar energy into electric energy or into a fuel such as hydrogen.

Abstract: An electrolyzer is provided for processing fluids. The electrolyzer includes electrode plates having laterally extending electrical busses. The electrode plates are mounted in a non-conducting external frame having a plurality of ducts for the flow of process fluids between the electrolyte chamber and the ducts. Seals are provided between the electrode plates and the external frame.

Abstract: An electrolytic cell having a plurality of porous and tubular cathodes, a plurality of porous anodes and a plurality of bag-shaped molds being formed by a cation exchange membrane in at least the portions facing and between the vertical faces of the anode and cathodes. The anode accommodating bag-shaped molds have apertures at the bottom through which anode connected electroconductive bars extend, said bars being inserted through and secured at corresponding cell bottom plate apertures by flanges. A partition plate, on the top of the cell main body, has a plurality of openings which correspond to the open tops of the bag-shaped molds. The open top edges of the bag-shaped molds are secured to the partition plate openings by a plurality of lid members.

Abstract: A device for supply or discharge of electrolyte for an electrolyzer of filterpress type has several compartments fed through channels (3) which open out into a common tranquilization chamber (4) of thin cross-section, which in turn is fed with electrolyte by way of a duct twisted, for example, into a spiral (51) of small cross-section.

Abstract: An electrolytic cell for the ion exchange membrane method, which comprises:(a) an electrolytic cell main body;(b) a lid covering the(c) porous and hollow tubular cathodes disposed in the body;(d) a bottom plate having apertures through which an electrically conductive bar can be extended;(e) electrically conductive bars provided with a flange at a lower portion thereof, each inserted through the apertures of the bottom plate into the interior of the body and secured to the bottom plate by the flange;(f) porous anodes each connected to the electrically conductive bar and placed vertically in a face-face relation to the cathode, and disposed between the cathodes;(g) bag-shaped elements, portions of which facing the anodes and the cathodes are formed by a cation exchange membrane, the bottom of which has at least one aperture through which the electrically conductive bar can be extended, and which have each an open top; and(h) a partition plate having openings, which plate is on the top of the body,whereinone or

Abstract: An electrolytic diaphragm cell for the electrolysis of an aqueous solution of an alkali metal chloride is comprised of a cell body having a porous diaphragm separating the cell body into an anode compartment and a cathode compartment. The anode compartment contains at least one anode and the cathode compartment contains at least one cathode. The cathode is comprised of a formaminous metal conductor and a reticulate cathode, with the reticulate cathode being positioned between and in contact with the porous diaphragm and the foraminous metal conductor. The cell has means adapted to supply electric current to the anodes and the cathodes, nd inlets and outlets in the cell body adapted to supply and remove fluids. The electrolytic diaphragm cell of the present invention operates at reduced electrical power consumption by employing three dimensional cathodes having increased internal surface area and increased porosity.

Abstract: An electrolytic cell of the filter press type comprising a monopolar cell unit having a plurality of substantially vertical alternating anodes and cathodes each anode being partitioned from the adjacent cathode or cathodes by a separator to form in the cell unit a plurality of anode and cathode compartments, the electrolytic cell comprising two or more such units mounted one above the other, the anodes of the cell unit at the top or bottom being attached to electrical conductors, the cathodes of the cell unit at the bottom or top being attached to electrical conductors, and the anodes and cathodes of adjacent cell units which are not attached to the said conductors being connected by means of a bipolar electrical connection or connections between the anodes of one cell unit and the cathodes of the adjacent cell unit positioned above or below the said cell unit.

Abstract: A composite fiber reinforced plastic frame and method of making such a frame are provided wherein a thin corrosion resistant liner material having a highly reinforced structural core is at least partially formed by wrapped roving layers of glass fiber impregnated with a catalyzed thermosetting resin that possesses high strength and a low coefficient of thermal expansion.

Abstract: An electrolyzer cell of the filter-press type intended to operate under high pressure and at high temperature is constructed of spacing frames (4) for supporting and joining the electrodes and the diaphrams (1). Each frame is constituted by several portions (41 to 44), each held at a fixed point (61 to 64) and slidingly joined to one another.

Abstract: Chromic acid is now efficiently prepared in a process using dichromate, such as the dichromate typically available as an intermediate in the chromic acid production from chrome ore. In the process, the dichromate is introduced into the center compartment of a three-compartment electrolytic cell and dichromate-containing center compartment electrolyte flows through a porous diaphragm into the anode compartment of the cell. Electrolyte is introduced to the cell cathode compartment which is separated from the center compartment by a substantially hydraulically impermeable cation-exchange membrane means. During electrolysis, chromic acid is prepared in the anolyte and alkali product is produced in the catholyte.

Abstract: A filter press type electrolytic cell for the electrolysis of brine to produce chlorine and caustic includes a plurality of rectangular frames having U-shaped or channel-shaped walls, the open sides of each of which wall members face inwardly, and a downcomer tube in each frame for conducting product from near the top of the frame to the bottom thereof for withdrawal. The downcomer tubes are located near a framing side but are not within a framing channel. The openings of the framing walls are partially covered by cross members of the same material as the framing to improve the resistance thereof to distortion during closing of the cell. Utilization of the downcomer tubes, preferably of polytetrafluoroethylene for the catholyte compartment and titanium or titanium clad material for the anolyte compartment, allows the maintaining of the framing channel open so that inner walls thereof are electrolytically protected against corrosion.

Abstract: Electrochemical systems having a plurality of cells which are hydraulically and electrically connected in series develop shunt currents in the electrolyte of adjacent cells. The shunt currents are reduced or eliminated by the placing of an electrical bypass across two adjacent intercell conduits, and applying a protective current through the electrical bypass in a direction of the shunt currents and of a magnitude that can effectively reduce the shunt currents.

Abstract: In a filter press membrane chloralkali electrolytic cell there is provided an improved external electrolyte recirculation system wherein the salt brine and deionized water replenisher feed lines are inserted individually within the electrolyte return conduits from each external gas-liquid disengager to thereby introduce feed electrolyte into a reservoir of electrolyte fluid which is in low resistance contact with the electrodes.

Abstract: A method of assembling an electrolytic membrane cell is disclosed. The method includes the steps of conditioning the membranes with a conditioning fluid, assembling a vertical stack of horizontal electrode frames with a horizontal membrane sheet between each pair of frames, applying pressure to vertically compress the vertical stack, rotating the compressed vertical stack from a vertical orientation through approximately 90.degree. in which orientation of the stack is called a "pack", connecting the pack into an electrical circuit and to raw material supply lines and product withdrawal lines and then electrically operating the pack while maintaining the pack in a horizontal orientation.

Abstract: In a filter press membrane chloralkali electrolytic cell having a plurality of electrodes with an external anolyte gas-liquid disengager in fluid flow communication with each anode via conduit means having a first predetermined cross-sectional area utilized to recirculate electrolyte from the disengager to each anode and electrolyte replenisher means connected to the disengager and each anode, there is provided an improved electrolyte recirculation system wherein the electrolyte replenisher means includes a plurality of feed pipes which are inserted individually within the conduit means thereby causing each feed pipe to be in fluid flow communication with each anode, each feed pipe further extending a predetermined distance into the conduit means from within the disengager and having a second predetermined cross-sectional area such that the outlet of flow of replenishing electrolyte is into the flow of recirculated electrolyte within the conduit means to effect maximum mixing of the fluids prior to entering e

Abstract: An improved gas generator comprising a multiplicity of electrolytic cells arranged to accommodate a series current path, parallel electrolytic flow and minimized leakage current paths, in a stacked plate configuration that affords a high degree of portability at low cost.

Abstract: Electrodes are disclosed which comprise a porous conductive material as a primary electrode component in electrical contact with a secondary electrode component which preferably is a metal, such as titanium. The secondary electrode component is normally conductive when operating as a cathode, and is capable of alternating between being non-conductive when operating as an anode and becoming conductive again when the electrode is operating as a cathode. Processes for removing metallic species from solution utilizing such electrodes are also disclosed.

Abstract: A method of varying the flow in a flow conduit from both the anolyte disengager and the catholyte disengager to each appropriately corresponding electrode is provided to selectively vary the flow rate of electrolyte fluids through the disengagers to the appropriate electrodes to thereby control the level of foaming of the electrolyte fluids within the disengagers to prevent the blowover of foam during the separation of entrained gas from the electrolyte fluids therein.

Abstract: The electrolysis device of the present invention comprises an elongated vertically disposed hollow housing having an upper end and an open lower end. The housing has at least one inlet opening spaced above the open lower end. An anode is placed within the hollow housing, and a cathode plate is detachably mounted to the lower end of the housing. An electrically operated impeller is mounted between the inlet opening and the open lower end of the housing, and it draws fluid within the inlet opening and drives it outwardly through the open lower end of the housing. The silver ions collect on the negatively charged cathode plate.

Abstract: A novel electrode for a monopolar filter press cell is disclosed which comprises a first foraminous surface and a second foraminous surface positioned in parallel and spaced apart, which are secured to conductor rods positioned in a cell frame. The frame has two side members, a top member and a bottom member attached to the first and second foraminous surfaces. A chamber is formed between the first and second foraminous surfaces and bounded by the frame. At least one pair of conductor rods pass through one of the side members of the frame into the chamber. One of the conductor rods in each pair is attached only to the first foraminous surface; the other conductor rod in the pair is attached only to the second foraminous surface. The frame has inlets and outlets for introducing fluids into and removing electrolysis products from the chamber.

Abstract: Improvements in electrolytic chlor-alkali membrane cells, operated with cell-to-cell catholyte series flow, are obtained by the use, as membranes, of fluoropolymers containing pendant functional groups on the cathode side which are less hydrophilic than sulfonic acid groups. Preferably the functional groups on the catholyte side of the membrane absorb about 5 to about 12 moles of H.sub.2 O per functional group whereas the functional groups on the anolyte side of the membrane absorb more, generally, about 15 to about 30 moles of H.sub.2 O per functional group.

Abstract: A novel electrode is disclosed for a filter press cell operating at medum pressure. This novel electrode comprises two vertical planar foraminous surfaces positioned in parallel and spaced apart, having at least one pair of conductor rods and a frame. The frame has two side members, a top member, and a bottom member, and is attached to the planar surfaces whereby a chamber is formed between the planar surfaces bounded by the frame. The foraminous surface has a tensile strength in the range from about 50 to about 300 pounds per lineal inch measured in the weakest direction of the foraminous surface. One conductor rod of each pair is attached to the frame along with one of the foraminous surfaces. At least one process connection for conveying process material into and out of the chamber is also provided in the frame.

Abstract: An electrode for a monopolar filter press cell comprises two vertical foraminous surfaces positioned in parallel and spaced apart. A frame having two side members, a top member, and a bottom member is attached to the foraminous surfaces. A chamber is formed between the foraminous surfaces and bounded by the frame. Conductor rods pass through one of the side members into the chamber; the conductor rods being spaced apart from the foraminous surfaces. The frame has inlets and outlets for introducing fluids into and removing electrolysis products from the chamber. The novel electrodes provide improved gas flow patterns by creating limited restrictions within the chamber so as to generate a Venturi or low pressure effect which pulls gases from the interelectrode gap through the electrode surfaces and into the chamber.

Abstract: Shunt currents can be eliminated in electrochemical devices by introducing nulling currents via auxiliary electrodes. The invention teaches the reduction or elimination of these shunt currents in such devices with minimized power consumption. Shunt current nulling tunnels are provided which interconnect with electrolyte supply channels feeding the cells of the electrochemical device. Power consumption for the shunt current-nulling tunnels is reduced by designing the tunnels to have an increasing electrical resistance towards their mid-portions. Another embodiment of the invention features an increasing electrical resistance towards the mid-portion of the tunnels and a decreasing electrical resistance towards the mid-portion of the manifolds.

Abstract: A method of assembling an electrolytic membrane cell is disclosed. The method includes the steps of assembling a vertical stack of horizontal electrode frames with a horizontal membrane sheet between each pair of frames, then applying pressure to vertically compress the vertical stack, then rotating the compressed vertical stack from a vertical orientation to a horizontal orientation in which orientation of the stack is called a "pack" and then connecting the pack into an electrical circuit and to raw material supply lines and product withdrawal lines and then electrically operating the pack while maintaining the pack in a horizontal orientation.

Abstract: Apparatus usable in the electrolytic treatment of electroactive species in a solution include a porous electrode which is supported across a fluid flow path in such a manner that fluid flowing along the flow path must pass through an effective portion of the electrode.

Abstract: Hydrochloric acid electrolyzers serve to decompose hydrochloric acid to hydrogen and chlorine with the aid of electric current.

Abstract: Concentrated alkali metal hydroxide substantially free of alkali metal halide and other impurities is produced by the electrolysis of an alkali metal halide solution in an electrolytic cell having a dimensionally stable anode and a metal cathode separated by an electrically conductive stable selectively permeable hydrated cation ion-exchange membrane film of a fluorinated copolymer having pendant sulfonic acid groups or derivatives of such groups. The membrane film is capable of use at high temperatures and under severely corrosive chemical conditions for extended periods without degradation.

Abstract: A filter-press type ion exchange membrane-method electrolysis cell comprising(a) an anode structure which comprises a rectangular anode frame including a top element, a bottom element and two side elements and anode plates welded to the anode frame,(b) a cathode structure which comprises a rectangular cathode frame including a top element, a bottom element and two side elements and cathode plates welded to the cathode frame, and(c) an ion exchange membrane interposed between the anode structure and the cathode structure;whereinthe two side elements of the anode frame and the two side elements of the cathode frame have a tubular structure with a rectangular cross section,the top and bottom elements of the anode frame and the top and bottom elements of the cathode frame have a .].

Abstract: A stream containing chromium and other heavy metals is fed through an electrolytic cell having a flow-through anode of lead shot and a flow-through cathode. The stream passes through the lead shot, resulting in the formation of lead chromate at the anode that falls to a trap in the bottom of the cell. Heavy metals such as copper are plated out on the material forming the flow-through cathode.

Abstract: An apparatus and method of monitoring temperature in a multicell electrolyzer used to produce a gaseous product from a liquid phase electrolyte by placing a single temperature sensing means in the common product collection means is disclosed.

Abstract: Disclosed is a method of operating a solid polymer electrolyte chlor-alkali cell at an elevated pressure with the recovery of liquid chlorine and brine. The liquid chlorine and depleted brine are recovered from the cell and separated. Thereafter, the brine may be dechlorinated, e.g., by cooling the brine to from chlorine hydrate, and separating the chlorine hydrate.

Abstract: The present invention is directed to a method of minimizing shunt currents in electrochemical devices which have a plurality of cells connected, at least in part, in series and which have a common electrolyte which is fed to at least two of the cells as a shared electrolyte from a common manifold via individual inlet channels, whereby an electrical electrolytic conductive bypass path is created around such cells and through said shared electrolyte, resulting in undesirable shunt currents. This method involves providing electrolyte tunnels which connect the individual inlet channels and applying a protective current through said electrolyte tunnels and thus through said shared electrolyte, the protective current being of a magnitude which effectively at least reduces said shunt currents. Thus, a single protective current may be applied such that shunt currents are minimized, and preferably are totally eliminated.