Abstract: The novel process of the invention produces chlorine dioxide by feeding an aqueous solution of chloric acid to a chlorine dioxide generator. The aqueous solution of chloric acid is reacted with a reducing agent in the chlorine dioxide generator to produce chlorine dioxide and a spent chloric acid solution containing metallic impurities. A portion of the spent chloric acid solution containing metallic impurities is reacted with a basic compound selected from the group consisting of alkali metal hydroxides, and alkali metal carbonates in a neutralizing zone to form a precipitate of the metallic impurities and an alkali metal chlorate solution. The precipitate of the metallic impurities is separated from the alkali metal chlorate solution and the alkali metal chlorate solution fed to an ion exchange compartment of an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment.

Abstract: An aqueous solution of chloric acid and alkali metal chlorate is produced in an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment.

Abstract: A process which comprises heating a reaction mixture comprised of an aqueous solution containing perchlorate ions, chlorate ions and hydrogen ions to produce chlorine dioxide and oxygen gas.The novel process of the present invention provides a commercially viable process for producing chlorine dioxide from mixtures of oxy-chlorine species in the absence of a reducing agent. The process can be operated without producing an acidic salt by-product while producing a chlorine dioxide product which is substantially free of chlorine. In addition, the process of the invention permits a reduction in the amount of acid fed to the chlorine dioxide generator.

Abstract: An electrolytic cell construction in which the cell includes at least one anode and cathode, and a separator therebetween held under a compressive force by a frame assembly. The anodes and cathode are provided with a portion for electrical connection to an electric connector plate. The electric connector plate is positioned in contact with a respective anode and cathode. The compressive force of the frame assembly which holds the components of the cell in compression to provide a fluid tight seal simultaneously serves to apply a force between the electrical connector plates and their respective anode or cathode to hold the electrical connector plates in contact therewith. Preferably spring means are provided for biasing the electrical connector plates and the portions of the anode and cathode for connection to the plate into engagement with each other.

Abstract: An electrode and an electrolytic cell in which the electrode includes a plate having electrode material attached to at least one side thereof. A header opening is provided in the electrode plate and has a plurality of slots radiating therefrom towards the center of the plate. The electrolytic cell includes an electrode spaced from a separator such as a membrane or diaphram by a gasket member of universal design. The electrodes, separator and gaskets have a header opening extending therethrough with slots radiating from the header openings in the anode and cathode plates to provide fluid communication between anode and cathode chamber and the header.

Abstract: A process for producing chlorine dioxide a solution of chloric acid is reduced in the presence of an externally added load of perchlorate ions to form chlorine dioxide.

Abstract: A process for treating solutions of a hydroxylammonium salt containing excess acid which comprises:a) mixing the hydroxylammonium salt containing excess acid with a hydroxylammonium solution containing free hydroxylamine to produce a solution of the hydroxylammonium salt substantially free of excess acid,b) contacting a portion of the solution of the hydroxylammonium salt substantially free of excess acid with a weak base ion exchange resin to produce the hydroxylammonium solution containing free hydroxylamine, and,c) recycling the hydroxylammonium solution containing free hydroxylamine to step a).The process minimizes the decomposition of the hydroxylammonium salt solution and produces high purity hydroxylammonium nitrate solutions without directly contacting excess nitric acid with ion exchange resins. In addition to hydroxylammonium salts, the process can be used to treat any nitrate salt of an anine weak base which contains excess nitric acid.

Abstract: A process for fabricating a porous, high surface area electrode and the use of that electrode in an electrolytic cell for manufacturing chlorine-free chlorine dioxide from dilute alkali metal chlorite solutions in a single step is disclosed. The electrolytic cell uses a porous flow-through anode and a cathode separated by a suitable separator.

Abstract: An aqueous solution of chloric acid and alkali metal chlorate is produced in an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment. The process comprises feeding an aqueous solution of an alkali metal chlorate to the ion exchange compartment, electrolyzing an anolyte in the anode compartment to generate hydrogen ions, passing the hydrogen ions from the anode compartment through a cation exchange membrane into the ion exchange compartment to displace alkali metal ions and produce an aqueous solution of chloric acid and alkali metal chlorate, passing alkali metal ions from the ion exchange compartment into the cathode compartment, removing the aqueous solution of chloric acid and alkali metal chlorate from the ion exchange compartment, and reacting the aqueous solution of chloric acid and alkali metal chlorate with a strong acid having a dissociation constant of 1.times.10.sup.

Abstract: A porous, high surface area electrode comprising a fine fibrous conductive substrate having a density less than about 50% and a specific surface area to volume ratio of greater than about 30 cm.sup.2 /cm.sup.3. The individual fibers of the substrate have a length to diameter aspect ratio greater than 1000:1. An electrocatalyst covers at least a portion of the substrate. A current distributor is electrically connected to the coated substrate. The method of fabricating the electrode includes fabricating a fine fibrous conductive substrate, preparing the surface of the substrate for receiving an electrocatalyst covering thereon, preparing the electrocatalyst for application to the substrate and applying the electrocatalyst to the substrate. Optionally, the electrode may be further treated to promote adhesion of the electrocatalyst to the substrate.

Abstract: A bipolar water ionizing electrode and a process employing such an electrode in an electrodialytic cell are disclosed. The cell has a plurality of ion exchange compartments separated by cation permselective membranes and the bipolar water ionizing electrode. The bipolar electrode is permeable to gas and electric current and impervious to liquid.

Abstract: A process for the separation of a mixture of zinc and manganese oxides by adding the mixture to a chloric acid solution whereby the chloric acid solution oxidizes solid manganese oxide to solid manganese dioxide and causes the zinc oxide to dissolve into soluble zinc ions. The solid manganese dioxide is then separated from the chloric acid solution containing zinc ions.

Abstract: A continuous process for producing chlorine dioxide which comprises feeding an aqueous solution of an alkali metal chlorate to a first ion exchange compartment of an electrolytic cell having an anode compartment, a cathode compartment and at least one ion exchange compartment between the anode compartment and the cathode compartment, electrolyzing an anolyte in the anode compartment to generate hydrogen ions, passing the hydrogen ions from the anode compartment through a cation exchange membrane into the first ion exchange compartment to displace alkali metal ions and produce an aqueous solution of chloric acid and alkali metal chlorate, passing alkali metal ions from the first ion exchange compartment into the cathode compartment, and reacting in a chlorine dioxide generator the aqueous solution of chloric acid and alkali metal chlorate substantially free of anionic and cationic impurities with a reducing agent which does not form persistent anions in the generator solution, to generate chlorine dioxide and

Abstract: A process of operating an electrochemical cell with a particular catholyte flow pattern is disclosed wherein the cell is angled from the horizontal and the catholyte is fed into a gap in the cathode compartment between the liquid metal cathode and the membrane on the lower first end and exits the gap on the opposing higher second outlet end.

Abstract: An aqueous solution of chloric acid and alkali metal chlorate is produced in an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment.

Abstract: A process for removing an ionic impurity from an impure substantially non-aqueous liquid passes the impure non-aqueous liquid through at least one ion exchange compartment containing an ion exchange medium. The ion exchange compartment is separated from an anode compartment and a cathode compartment by ion exchange membranes, where the ion exchange membranes and ion exchange medium having functional groups of the opposite charge as that of the ionic impurity. An electric current is conducted across the ion exchange compartment substantially transverse to the direction of flow of the impure non-aqueous liquid, and transporting the ionic impurity through an ion exchange membrane to separate the ionic impurity from the non-aqueous liquid.

Abstract: A process for producing chlorine dioxide is provided which reacts an aqueous solution of chloric acid and an alkali metal chlorate with a solution of a non-oxidizable acid in the presence of an oxygen-evolving catalyst in a reaction zone to produce a gaseous mixture of chlorine dioxide gas, oxygen, water vapor and an aqueous solution of the non-oxidizable acid and an alkali metal salt of the non-oxidizable acid. The gaseous mixture of chlorine dioxide gas and oxygen are separated from the aqueous solution of the non-oxidizable acid and alkali metal salt of the non-oxidizable acid, while the aqueous solution of the non-oxidizable acid and alkali metal salt of the non-oxidizable acid is fed to the anode compartment of three compartment electrolytic cell having at least one ion exchange compartment between an anode and a cathode compartment.

Abstract: An aqueous solution of chloric acid and alkali metal chlorate is produced in an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment, in a process which comprises:a) feeding an aqueous solution of an alkali metal chlorate to the ion exchange compartment,b) passing hydrogen and alkali metal ions from the anode compartment through a cation exchange membrane into the ion exchange compartment, wherein the hydrogen ions displace alkali metal ions to produce an aqueous solution of chloric acid and alkali metal chlorate,c) passing alkali metal ions from the ion exchange compartment into the cathode compartment,d) electrolyzing the aqueous solution of chloric acid and alkali metal chlorate in the anode compartment to produce an aqueous solution of chloric acid, alkali metal chlorate, hydrogen ions and perchlorate ions as a minor constituent.

Abstract: An aqueous solution of chloric acid and alkali metal chlorate is produced in an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment.

Abstract: A process for producing chlorine dioxide from an aqueous solution of chloric acid and alkali metal chlorate which is prouced in a electrolytic cell having an anode compartment, a cathode compartment and at least one ion exchange compartment between the anode and cathode compartments. The process includes the steps of feeding an aqueous solution of an alkali metal chlorate to the ion exchange compartment, electrolyzing an anolyte in the anode compartment to generate hydrogen ions, passing the hydrogen ions from the anode compartment through a cation exchange membrane into the ion exchange compartment to displace alkali metal ions and produce an aqueous solution of chloric acid and alkalimetal chlorate, passing the alkali metal ions from the ion exchange compartment into the cathode compartment, and finally passing the aqueous solution of chloric acid and alkali metal chlorate to a chlorate dioxide generator.