Olin Corporation

Sterling Pulp Chemicals, Ltd.

Jerry J Kaczur

David W Cawlfield

Kenneth E Woodard, Jr

Budd L Duncan

Sudhir K Mendiratta

Steven A Iacoviello

Julian F Watson

Larry D Carpenter

Edward G Miller

Ronald L Dotson

Marek Lipsztajn

Gerald Cowley

John J Simmons

J Paul Deininger

Robert T Brooker

Paul J Craney

Elizabeth K Muse

James C Tyler, Jr

John E Coleman

Hassan Arabghani

Cortie J Rolison, Iii

A process for converting in a single pass an aqueous alkaline pH, alkali metal chlorite solution into an aqueous chlorine dioxide-containing solution that involves the combination of (1) using an electrochemical acidification cell to lower the pH value of the aqueous alkali metal chlorite feed before it enters the anode compartment of an electrochemical oxidation cell where the chlorite is converted to chlorine dioxide with (2) using an anolyte flow pattern where the anolyte passes through a porous, high surface area electrode. This process results in a substantially improved conversion efficiency per pass.

Electrolytic process for producing chlorine dioxide

A process and apparatus for producing chlorine dioxide comprising chemically reducing chloric acid with water in the presence of any oxygen-evolving catalyst and in the absence of another acid or an added reducing agent, thereby producing chlorine dioxide and oxygen.

Catalytic process for chlorine dioxide generation from chloric acid

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.

Water ionizing electrode and electrochemical process for using

A process for removing alkaline earth metal impurities (e.g. calcium and magnesium ions) from an aqueous alkali metal chlorate solution which includes adding sufficient alkali metal carbonate or hydroxide or both to the impure solution to raise the pH to above 9 and form alkaline earth metal precipitates which are then removed from the pH-adjusted solution (e.g. by microfiltration). This process can lower the level of these impurities from about 1-20 ppm to less than about 0.3 ppm or less.

Purification of aqueous alkali metal chlorate solutions

The present invention relates to an electrochemical process for the removal of excess or residual nitric acid from aqueous hydroxylammonium nitrate (HAN) solutions. The process utilizes a multi-compartment electrochemical membrane cell in which the HAN solution flows through a central ion exchanging compartment bounded by anion membranes on either side. Electrochemically generated OH-ions formed at the cathode are used to displace and remove the nitric acid from the HAN solution. In use, the residual nitric acid content in the HAN is suitably reduced to a specified safe level before the HAN is concentrated to a 13.0 molar final composition.

Electrochemical process for the removal of residual nitric acid from

A process for electrochemically treating an aqueous solution containing inorganic oxynitrogen species is disclosed in which the aqueous solution is fed into the catholyte compartment of an electrochemical reduction cell using a high surface area cathode separated from an anolyte compartment to electrochemically reduce substantially all of the oxynitrogen species to nitrogen or ammonia and produce a purified water product.

Process for the removal of oxynitrogen species for aqueous solutions

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. Electrolysis of an anolyte in the anode compartment generates hydrogen ions which pass 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. The aqueous solution of chloric acid and alkali metal chlorate is returned to the chlorine dioxide generator. The process of the invention produces chlorine dioxide free of chlorine from mixtures of oxy-chlorine species. A continuous removal of metallic impurities permits avoiding or significantly increasing the time period between generator shutdowns.

Effluent treatment in a process for producing chlorine dioxide from

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, increasing the chlorate ion concentration to provide the aqueous solution of chloric acid and alkali metal chlorate with a total chlorate ion to water molar ratio of about 0.15 or greater.

Chloric acid - alkali metal chlorate mixtures and chlorine dioxide

A process for removing NO.sub.x oxides and SO.sub.x oxides from gaseous streams contacts the gaseous stream with an aqueous solution of chloric acid. The process of the invention removes sulfur oxides and nitrogen oxides from waste gas streams without producing inorganic salts. In addition, the use of chloric acid provides improved oxidation of NO and SO.sub.2. The process can be operated to treat 'dirty' gas streams containing particulates and compounds which may poison or contaminate NO.sub.x removal systems employing catalysts.

Process for removal of NO.sub.x and SO.sub.x oxides from waste gases

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.

Chlorine dioxide generation using inert load of sodium perchlorate

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.

Process for producing an electrode by electroless deposition

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.-4 or greater and a reducing agent to generate chlorine dioxide gas.

Electrochemical process for generating chlorine dioxide using chloric

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.

High surface area electrode structures for electrochemical processes

Electrodialytic process for producing an alkali solution

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 to form an alkali metal chlorate precipitate. The alkali metal chlorate precipitate is recycled by dissolving the precipitate into the alkali metal chlorate feed stream that is fed to the first ion exchange compartment of the electrolytic cell.

Growing community of inventors

Cleveland, TN, United States of America

Jerry J Kaczur