Abstract: A method for fabricating a silicon membrane with predetermined stress characteristics. A silicon substrate is doped to create a doped layer as thick as the desired thickness of the membrane. Stress within the doped layer is controlled by selecting the dopant based on its atomic diameter relative to silicon and controlling both the total concentration and concentration profile of the dopant. The membrane is then formed by electrochemically etching away the substrate beneath the doped layer.

Abstract: An abrasion-resistant, tear-resistant, multilayer composite membrane, useful in electrolysis, is provided comprising a continuous perfluoro ion exchange polymer film attached to a reinforcing fabric by means of a porous, expanded polytetrafluoroethylene (EPTFE) interlayer. The fabric and EPTFE are rendered hydrophilic and non-gas-locking by coating the interior and exterior surfaces thereof with a perfluoro ion exchange resin of equivalent weight less than 1000. The composite preferably is treated with an ionic perfluoro surfactant. Also provided is a multilayer composite according to the above in which the continuous perfluoro ion exchange film is itself a multilayer construction of a perfluorosulfonate polymer and a thin layer of perfluorocarboxylate polymer in which the perfluorosulfonate polymer interfaces with the EPTFE and the interior and exterior surfaces of the EPTFE and fabric are coated with perfluorosulfonate polymer.

Abstract: A composite hydrogen purification membrane comprises an anode for hydrogen oxidation, a cathode for hydrogen reduction, with a proton conductor disposed between and in contact with the anode and the cathode. Electrons are conducted between the anode and cathode through an external connection, with the electron flow generated by the difference in hydrogen partial pressure between the anode and cathode sides of the membrane. Thus the composite hydrogen purification membrane provides high hydrogen permeability and selectivity relative to the impurities in a feed gas, producing pure hydrogen without requiring an external voltage source.

Abstract: Disclosed is a method of carrying out a mobile atom insertion reaction, such as a hydrogen insertion reaction, for the synthesis of reduced, hydrogenated compounds. Such reactions include the production of ammonia and hydrazine from nitrogen, formic acid and methanol from carbon dioxide, and hydrogen peroxide from oxygen. The insertion reactions are carried out at a bipolar mobile atom transmissive membrane comprising a membrane formed of a mobile atom pump material, as a hydrogen pump material, conductive atom transmissive means on one surface of the membrane and conductive atom transmissive means on the opposite surface of the membrane. The mobile atom, such as hydrogen, diffuses across the membrane, to provide a source of hydrogen on the insertion reaction side of the membrane. The insertion reaction side of the membrane is positively biased with respect to a counterelectrode so that a reactant molecule, such as carbon dioxide, is electrosorbed on that surface of the membrane.

Abstract: A method for making light metal-alkali metal master alloy using alkali metal containing scrap comprises: (a) establishing an electrolytic cell divided into two or more laterally adjacent areas by porous alkali metal ion transport means, said cell including a first cell area supplied with alkali metal-containing scrap and a second cell area consisting essentially of molten light metal; (b) supplying current to this cell for transporting alkali metal ions from the first cell area to the second cell area; (c) forming master alloy by combining these ions with the molten light metal in said second cell area; and (d) withdrawing master alloy from the second cell area. An apparatus for making aluminum-lithium or magnesium-lithium master alloy using the lithium from aluminum-lithium alloy scrap is also disclosed.

Abstract: An electrolyte permeable asbestos diaphragm is prepared by depositing asbestos and a particulate thermoplastic polymeric material from an aqueous slurry including alkali metal hydroxide onto a porous substrate, and heating the deposited asbestos, particulate thermoplastic polymeric material, and alkali metal hydroxide for a period of time, e.g., at least 2 hours, and at temperatures sufficient to react the asbestos and alkali metal hydroxide but temperatures insufficient to melt or sinter the particulate thermoplastic polymeric material, whereby the particulate thermoplastic polymeric material functions to provide permeability for the diaphragm.

Abstract: Disclosed is an improved electrolytic cell comprising a microporous separator of the diaphragm type, anolyte and catholyte compartments made of plastic materials and metal electrodes with a multipicity of perforations in the electrochemically active area made preferentially by punching perforations of pre-selected shapes. Also disclosed is the presence of a separation chamber located on top and being an integral part of the anolyte compartment for separating the anodic gases from the expent anolyte solution. Also disclosed are methods for mounting and sealing all of the elements of the electrolytic cell that allow for differences in the thermal expansion of the metal and plastic parts. Further disclosed is a method for attaching together several cells to form a stack, where the cells within the stack can be connected in series or in parallel.

Abstract: An electrolyte permeable diaphragm consisting essentially of asbestos is prepared by depositing asbestos and a porosity control agent selected from the group of cellulosic-type materials, e.g., starch, cellulose or rayon, infusible thermoset polymer materials, e.g., phenol-formaldehyde resin, urea-formaldehyde resin or melamine-formaldehyde resin, and inorganic materials, e.g., fiberglass, graphite, titania, silica, talc, vermiculite or potassium-containing mica from an aqueous slurry including alkali metal hydroxide onto a porous substrate, the porosity control agent being substantially stable and insoluble in the aqueous alkali metal hydroxide-containing slurry, followed by heating the deposited asbestos, porosity control agent and alkali metal hydroxide at temperatures between about 110.degree. C. and 280.degree. C. for a period of time sufficient to react the asbestos and alkali metal hydroxide whereby the porosity control agent provides the permeability for the diaphragm.

Abstract: A method and apparatus for refining elemental sulphur and hydrogen gas from H.sub.2 S is disclosed. More specifically, the present invention relates to a method and apparatus for vapor phase electrolysis of H.sub.2 S gas using a molten polysulfide electrolyte disposed in a matrix.

Abstract: An improved diaphragm for an electrolytic cell is prepared by mixing a slurry of an additive, such as poly(ethylene chlorotrifluoroethylene), and asbestos fibers with a dispersion of titanium dioxide in isopropyl alcohol, depositing the treated asbestos fibers onto a cathode, heating the diaphragm to an elevated temperature of from about 100.degree. C. to about 400.degree. C., and allowing the diaphragm to cool.The diaphragm prepared according to this process exhibits improved mechanical strength and integrity as well as a decrease in electrical energy consumption in comparison to diaphragms prepared using conventional techniques.

Abstract: An electrolyte permeable asbestos diaphragm is prepared by depositing asbestos and a particulate thermoplastic polymeric material from an aqueous slurry including alkali metal hydroxide onto a porous substrate, and heating the deposited asbestos, particulate thermoplastic polymeric material, and alkali metal hydroxide for a period of time, e.g., at least 2 hours, and at temperatures sufficient to react the asbestos and alkali metal hydroxide but temperatures insufficient to melt or sinter the particulate thermoplastic polymeric material, whereby the particulate thermoplastic polymeric material functions to provide permeability for the diaphragm.

Abstract: A process and apparatus for electrochemically separating alkali oxides to simultaneously generate oxygen gas and liquid alkali metals in a high temperature electrolytic cell is provided. The high temperature electrolytic cell comprises a cathode in contact with an alkali ion conducting molten salt electrolyte separated from the anode by an oxygen vacancy conducting solid electrolyte. Alkali metals separated in the alkali metal reducing half cell reaction are useful as reducing agents in the direct thermochemical refining of lunar metal oxide ores to produce metallic species and alkali oxides, and the alkali oxides may then be recycled to the high temperature electrolytic cell.

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: An electrochemical cell having a hydraulically impermeable permselective membrane is operated more efficiently by (1) separating the anode and the cathode of such a cell from the permselective membrane by a spacing means which is porous, hydrophilic, and electrically non-conductive, or alternatively, (2) providing a coating on the metal electrodes of said cell which is hydrophilic, porous, and electrically non-conductive. Said spacing means is of a material selected from the group consisting of at least one of mineral fibers, synthetic organic polymers, and ceramics and glasses.

Abstract: An improved diaphragm for an electrolytic cell is prepared by mixing a slurry of asbestos fibers with a dispersion of titanium dioxide in isopropyl alcohol, depositing the treated asbestos fibers onto a cathode, heating the diaphragm to an elevated temperature of from about 100.degree. C. to about 300.degree. C., and allowing the diaphragm to cool.The diaphragm prepared according to this process exhibits improved mechanical strength and integrity as well as a decrease in electrical energy consumption in comparison to diaphragms prepared using conventional techniques.

Abstract: The present invention is a layered article of manufacture or quilt suitable to be useful to construct an electrolytic cell for manufacturing hydrogen peroxide. In use the quilt is placed upon a planar anode and the upper surface contacted with a current collector.

Abstract: A process for manufacturing a partially permeable membrane is such that a 20-200 .mu.m thick aluminum foil in the non-recrystallized condition is etched in an electrolyte at a current density in the range 2-20 kA/m.sup.2 and the surface given an after-treatment to prevent hydration reactions. The membrane is particularly suitable for ultrafiltration, gas separation or pervaporation and to that end can also be employed in combination with a polymer membrane.

Abstract: A process for manufacturing a microfilter is such that a foil having an aluminum content of at least 99.95% and thickness 20-250 .mu.m is given a recrystallizing anneal, is etched in an electrolyte in stages at constant current density in the range 0.01 to 2 kA/m.sup.2, and the surface given a stabilizing after treatment to prevent hydration reactions.

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: In one aspect a woven diaphragm for use in an electrolytic or in an electrochemical cell. The diaphragm is woven with yarns made from synthetic hydrophobic staple fibers having a linear density between about 1 and 10 denier. The diaphragm is between about 0.005 and 0.150 inches thick and has a weight between about 0.1 and 3.0 pounds per square yard. The diaphragm provides desirable ionic and hydraulic flow rates and a desirable cross cell voltage differential in operation of the cell.

Abstract: A dimensionally stable asbestos diaphragm is formed by direct coating on the foraminous cathode of an electrolytic cell from an asbestos fiber-particulate polymer slurry, followed by fusion of the thermoplastic polymer.

Abstract: A polymeric metal oxide such as polytitanic acid, polyzirconic acid or polysilicic acid is incorporated into a liquid permeable diaphragm formed of, e.g., asbestos, asbestos and a polymer resin, polytetrafluoroethylene, or a major amount polyfluorocarbon fibrils and a minor amount perfluorinated ion exchange material. Optionally, the diaphragm may also include inorganic materials such as zirconium oxide, titanium dioxide, aluminum oxide, talc, barium sulfate or potassium titanate, and hydrous inorganic gels such as magnesium oxide gel, zirconium oxide gel, titanium oxide gel or zirconyl phosphate gel.

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: A diaphragm for alkaline electrolysis, specifically for alkaline electrolysis of water, comprises a fine-pored, predominantly ceramic layer, which is preferably supported by a superficially oxidized structural framework or mesh. The diaphragm in use is sandwiched between two electrodes and is provided, on one or both sides, with fairly coarse-grained protuberances distributed over the surface and embedded into the fine-pored predominantly ceramic layer, which grains project out of the diaphragm surface. In view of the projection of the grains to form protuberances, and in spite of the fact that the adjacent electrodes are in contact with the diaphragm, a certain minimum distance is maintained between the diaphragm and each electrode, whereby, deposits on the electrodes, caused by unavoidable corrosion phenomena within the electrolysis apparatus, cannot propagate into the diaphragm.

Abstract: A process and apparatus for reducing carbon dioxide to at least one useful product includes two redox couple electrolyte solutions separated by a first membrane having photosensitizers. The carbon dioxide to be reduced is provided to a second membrane whch is contiguous to one of the redox couple electrolyte solutions. The second membrane has photosensitizers and a catalyst. Water provides hydrogen ions, which participate in the reduction of the carbon dioxide, via a separator. In operation both membranes are illuminated and produce excited photosensitizers which cause electron transfer from a first redox solution to a second redox solution and thence to the carbon dioxide in the second membrane thereby, in cooperation with the hydrogen ions, reducing at least some of the carbon dioxide at a surface of the second membrane to provide at least one product.

Abstract: The thermally insulated cell comprises: a trough with a steel shell which is surrounded by an outer wall, is lined with a material which is resistant to electrolyte and high temperatures, and is closed by a lid; an electrolyte based on alkali chlorides; segregation wells for the addition of aluminum which is to be purified and for the precipitation of impurity crystals; a supply means which is used to feed-in electrolyte material and is also conceived as a waste gas extractor; a collection and run-off system for the high purity aluminum. Provided in the interior of the cell are bipolar electrode units which are connected electrically in series and are arranged immersed in the electrolyte parallel to the end electrodes. The electrode units comprise graphite frames closed and sealed off by a diaphragm plate, which can be wet by the electrolyte but not by the aluminum. The interpolar distance between the inner side of the diaphragm plate and the cathodic graphite frame is preferably 10-25 mm.

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 improved electrolytic reactor is provided with a sealed enclosure subdivided into separate solution chambers for an anolyte and for a catholyte by the interposition of an electrically insulating septum with a microporous matrix. The microporous membrane, or septum, permits the controlled passage of ionic species but prevents the gross intermixing of the separate electrolytes in respective contact with the cathode and the anode of the reactor. At least one of the chambers defined on either face of the microporous septum is filled with electrically conductive particulate material--stainless steel balls in one embodiment--acting as extensions of the electrode in that chamber, so as to increase the electrically charged, stable surface available for electrolytic mass transfer.

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: The invention concerns a NiO-based ceramic oxide diaphragm for the alkaline water electrolysis. The diaphragm, in accordance with the invention, contains 0.5 to 10% by weight (estimated as Ti based on the oxide mass) of titanium oxide in the porous NiO layer. Diaphragms of this type are obtained, in particular, by the oxidative sintering of a mass of nickel powder which has been applied under pressure to a nickel support, especially one consisting of nickel wire gauze. In the process the titanium is in the form of titanium metal, titanium oxide or a titanium compound which is added to the initial nickel powder. The titanium is present in the form of its oxide after the oxidation sintering treatment. In an alternative embodiment of the process, an already sintered porous mass of nickel or nickel oxide can be impregnated with a titanium compound and calcined to convert the titanium compound to its oxide.

Abstract: The hydrophilicity and other properties of fluoropolymer-bonded asbestos diaphragms for use in brine electrolysis cells are improved by incorporating Na.sub.2 CO.sub.3 into the aqueous slurry from which the diaphragms are prepared.

Abstract: An exchangeable separator is horizontally located within a three-layer refining cell for the electrolytic purification of aluminum. This separator is freely movable in the vertical direction within a movement space (h) defined by a refractory frame. The porosity of the separator is at least 30%, preferably at least 50%, so that the electrolyte and metal can pass through the separator without any significant additional loss of potential.In industrial refining cells, the separator appropriately has a thickness of 0.5 to 2 cm and a disc-shaped design, the vertical movement space (h) being 0.5 to 1 cm. The level changes produced during the operation of the cell can be compensated for in this free movement space.

Abstract: Oxygen ion conducting ceramic materials are disclosed, represented by the formulasNi(Nb.sub.1-x M.sub.x).sub.2 O.sub.6-x and Ni.sub.2 (Nb.sub.1-x M.sub.x).sub.2 O.sub.7-x,wherein M is selected from the group consisting of Zr.sup.+4, Ti.sup.+4, Sn.sup.+4, Sm.sup.+4, Hf.sup.+4 and Ce.sup.+4 and x is a value from 0 to 0.2. These materials, along with Bi.sub.2 O.sub.3 in solid solution with Y.sub.2 O.sub.3 or Nb.sub.2 O.sub.5, may be used in an oxygen separator for removing oxygen from a first gas to a second gas or vacuum. The oxygen separator includes at least one layer of the ceramic material with layers of a porous metallic conductor arranged on either side to form a body. An electrode connects one layer, and a second electrode connects the opposite metallic layer. A voltage signal is applied across the electrodes, whereupon oxygen ions diffuse through the ceramic layer.

Abstract: A narrow gap electrolysis cell has anode and cathode compartments divided by an ionically-permeable separator, such as an ion-exchange membrane or a fibrous diaphragm, and a current feeder grid in electrical contact with a surface-activated particulate electrocatalytic material carried on a face of the separator. The particulate material has cores of a corrosion-resistant material preferably valve metal particles or sponge, or compounds thereof, as well as asbestos fibres and fibres of ion-exchange copolymeric perfluorocarbons, coated with a platinum-group metal catalyst in metal or oxide form. The surface-activated particles may be at least partly carried by a flexible electronically conductive foil between the current feeder grid and the separator.

Abstract: A porous diaphragm for an electrolytic cell for the electrolysis of alkali metal halides is comprised of a thermoplastic support fabric impregnated with particles of a siliceous composition. The thermoplastic support fabric has an anode side, a cathode side opposite the anode side, and a thickness of at least 0.3 millimeters. The cathode side has a greater hydrophobicity than the anode side. To provide greater hydrophobicity which results in controlled, reduced cell voltages, for example, the cathode side of the support fabric is treated with an oxidizing agent.

Abstract: A woven diaphragm for a diaphragm electrolysis cell for electrolysis of aqueous solutions containing ions such as alkali metal ions, chloride ions, and sulfate ions which diaphragm comprises warp threads and weft threads. Both warp threads and weft threads are of multifil filaments. Weft threads contain less than about 200 per meter and warp threads contain less than 400 per meter.

Abstract: The hydrophilicity and other properties of fluoropolymer-bonded asbestos diaphragms for use in brine electrolysis cells are improved by incorporating Na.sub.2 CO.sub.3 into the aqueous slurry from which the diaphragms are prepared.

Abstract: A method for treating an electrolytic diaphragm formed by adhering asbestos fibers to the surface of an electrolytic cathode made of a wire mesh or porous plate, which comprises permeating water glass into the diaphragm, then permeating a chloroprene latex into the water glass-treated diaphragm, and drying the treated diaphragm under heat.

Abstract: The process relates to the formation of diaphragms, for example those used for alkali chloride electrolysis in an aqueous solution. The formation of a layer-type diaphragm, accreted on a hollow diaphragm support from a slurry having a high solids content of diaphragm material, is made uniform.During the accretion step, the diaphragm support is periodically lifted and lowered in the slurry (frequency 0.1-10 min.sup.-1 ; amplitude 10-100 cm; velocity 2-20 cm/sec); its topside, at the upper reversal point of the oscillating motion, has a certain spacing (10-25 cm) from the constantly measured height of the level of slurry in the accretion tank and its underside cannot reach below a minimum distance (30 cm) from the bottom of the basin. The suction pressure of the slurry through the hollow diaphragm support is maintained at a constant value and is controlled (10-500 mbar below the atmospheric pressure of the surroundings).

Abstract: An improved diaphragm for electrolysis, said diaphragm being composed of a fibrous base material of asbestos or a mixture of asbestos and fluorine-containing fibers and existing in the interstices of said base material, a water-swellable micaceous mineral represented by the following general formulaW.sub.1/3-1.0 [X.sub.2.5-3.0 (Z.sub.4 O.sub.10)F.sub.2 ]wherein W is Na and/or Li, X is Li and/or Mg, Z is Si and/or Al, O is oxygen and F is fluorine. The diaphragm can be produced by dispersing a fibrous base material of asbestos or a mixture of asbestos and fluorine-containing fibers in an aqueous slurry of the water-swellable micaceous mineral being partly in the form of a sol or in a mixture of it with an aqueous solution of sodium hydroxide and/or sodium chloride, forming the dispersion into a sheet, and drying the sheet.

Abstract: A porous diaphragm for an electrolytic cell for the electrolysis of alkali metal halides is comprised of a thermoplastic support fabric impregnated with particles of a siliceous composition. The thermoplastic support fabric has an anode side, a cathode side opposite the anode side, and a thickness of at least 0.3 millimeters. The cathode side has a greater hydrophobicity than the anode side. To provide greater hydrophobicity which results in controlled, reduced cell voltages, for example, the cathode side of the support fabric is treated with an oxidizing agent.

Abstract: Porous separators for electrolytic processes are designed which are characterized by an N.sub.mac t value, where N.sub.mac is the ratio of the resistance (r) of the electrolyte-saturated separator to the resistance (r.sub.o) of an equivalent volume of electrolyte and t is the thickness, in inches, of the separator. The N.sub.mac value is referred to here as the MacMullin Number.

Abstract: The invention concerns an electrolyzer for alkaline water electrolysis whose cells are formed by a diaphragm provided with electrodes between 2 bi-polar separator plates as well as a process for the construction thereof.

Abstract: Diaphragm coated electrodes, processes for producing these diaphragm coated electrodes, and application of the diaphragm coated electrodes in electrolytic cells used in the electrolysis of brine to produce chlorine and caustic are disclosed.

Abstract: A method of cladding a separator, that is a diaphragm or membrane, to a cathode box of the pocket type comprising a plurality of foraminate walls, the method comprising positioning a separator in the form of a sleeve in each pocket of the cathode box with the ends of the sleeves projecting beyond the ends of the pockets and heat sealing by means of radio frequency heating those parts of the sleeves projecting beyond the ends of adjacent pockets, either to each other or to additional heat sealable material. Also a cathode box clad with separator, and an electrolytic cell comprising a cathode box clad with separator.

Abstract: Diaphragms for use in electrolytic cells, e.g., chlor-alkali cells, are beneficially prepared using pulverized expanded vermiculite in place of the historically popular asbestos.

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 electrochemical cell used to separate gas from a gaseous mixture by reduction of said gas at the cathode and regeneration of said gas at the anode is characterized in that one or more substances formed during the cathodic reduction and/or the anodic regeneration is chemically converted, preferably by catalytic decomposition, to produce further quantities of said gas, the gas formed by both the anodic regeneration and the chemical conversion being recovered as the product. In an especially preferred embodiment a plurality of said cells are used in apparatus for extracting oxygen from the air by using a cathode comprising high surface area graphite powder which reduces oxygen to produce peroxyl ions, each cell being further provided, externally of the cathode compartment, with means for catalytically decomposing the peroxyl ions produced, suitable catalysts being CoFe.sub.2 O.sub.4 or NiCo.sub.2 O.sub.4.

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.