Abstract: The present invention provides electrodes comprising a core substrate, and internal layer coating, and an external layer coating and processes to prepare such electrodes.

Abstract: A storage and transport system for sodium hypochlorite pentahydrate (solid bleach) is provided. The system includes a container configured to receive and store crystalline solid bleach that includes of at least forty percent sodium hypochlorite, and to retain decomposition components from crystalline solid bleach stored in the container. The container includes a containment wall at least partially surrounding an interior containment space configured to receive solid bleach therein. A passage extends from exterior the container to the interior containment space. The passage is configured for solid bleach to pass therethrough. A liner is located at an interior surface of the containment wall. The liner is substantially non-reactive with solid bleach and, without leakage, capable of retaining within the containment space: (a) solid bleach, (b) decomposition components of solid bleach and (c) liquid bleach formed when dissolving water is added to solid bleach within the containment space.

Abstract: Disclosed herein are processes for producing highly concentrated bleach slurries containing a mixture of crystals of solid sodium hypochlorite pentahydrate in a liquid phase saturated in sodium hypochlorite and containing sodium hydroxide or other alkaline stabilizers. Bleach slurries and compositions exhibiting enhanced stability are also disclosed.

Abstract: Disclosed herein are processes for producing highly concentrated bleach slurries containing a mixture of crystals of solid sodium hypochlorite pentahydrate in a liquid phase saturated in sodium hypochlorite and containing sodium hydroxide or other alkaline stabilizers. Bleach slurries and compositions exhibiting enhanced stability are also disclosed.

Abstract: The present invention provides compositions comprising comminuted sodium hypochlorite pentahydrate crystals with an average length-to-diameter ratio of less than about 20:1, and a mother liquor saturated in sodium hypochlorite, which has excess alkalinity and/or one or more additional alkali or alkali earth metal salts. Processes for preparing these compositions will be presented.

Abstract: The present invention provides compositions comprising comminuted sodium hypochlorite pentahydrate crystals with an average length-to-diameter ratio of less than about 20:1, and a mother liquor saturated in sodium hypochlorite, which has excess alkalinity and/or one or more additional alkali or alkali earth metal salts. Processes for preparing these compositions will be presented.

Abstract: A sodium hypochlorite composition comprising between about 25% and about 40% sodium hypochlorite, in the form of a slurry of sodium hypochlorite pentahydrate crystals in a mother liquor saturated in sodium hypochlorite. The composition can include sodium chloride, and an alkai stabilizer such as sodium hydroxide and sodium carbonate. The slurry is preferably between about ?15° C. and about 10° C. A method of transporting or storing sodium hypochlorite is also provided in which the sodium hypochlorite is in the form of a slurry of sodium hypochlorite pentahydrate crystals in a mother liquor saturated in sodium hypochlorite. The composition can include sodium chloride, and an alkali stabilizer such as sodium hydroxide and sodium carbonate. The slurry is preferably between about ?15° C. and about 10° C.

Abstract: A sodium hypochlorite composition comprising between about 25% and about 40% sodium hypochlorite, in the form of a slurry of sodium hypochlorite pentahydrate crystals in a mother liquor saturated in sodium hypochlorite. The composition can include sodium chloride, and an alkai stabilizer such as sodium hydroxide and sodium carbonate. The slurry is preferably between about ?15° C. and about 10° C. A method of transporting or storing sodium hypochlorite is also provided in which the sodium hypochlorite is in the form of a slurry of sodium hypochlorite pentahydrate crystals in a mother liquor saturated in sodium hypochlorite. The composition can include sodium chloride, and an alkali stabilizer such as sodium hydroxide and sodium carbonate. The slurry is preferably between about ?15° C. and about 10° C.

Abstract: Automatic control systems, and corresponding processes, for controlling either an anode adjuster in a chlor/alkali cell or at least one average middle temperature of a distillation column wherein the combination of feedback control from at least one real unit operation variable and an embedded real-time dynamic simulation of that variable are used.

Abstract: The present invention relates to a multi-step process for producing HAN that is free of ammonium nitrate. The process comprises the steps of: (a) stripping ammonia from an ammonia-containing, aqueous hydroxylamine solution having a hydroxylamine concentration of at least 10% by weight based upon the weight of the hydroxylamine solution, by contacting the ammonia-containing hydroxylamine solution with a stripping agent selected from the group consisting of inert gases and steam to provide an ammonia-free, aqueous hydroxylamine solution, and (b) reacting the ammonia-free, aqueous hydroxylamine solution with aqueous nitric acid having an acid concentration of at least about 0.1%, preferably at least about 20%, based upon the weight of the aqueous nitric acid, to produce ammonium nitrate-free HAN. In another process embodiment of the invention, the above-described ammonia stripping step is not required, and the hydroxylamine concentration is at least about 0.

Abstract: 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.

Abstract: A model predictive control apparatus and method for controlling the operation of a process having a process input signal and a process output signal, which includes determining a predicted process output signal at a future steady state condition according to a process model, determining a steady state error signal according to the difference between the predicted process output signal and a desired set point signal, and determining a set of future process input change signals required to correct for the estimated steady state error by providing at least one step response in the process output at a future time. The next net process input change is then applied according to the sum of the currently determined first element of the set of future process input change signals summed with any future process input change signals that were previously calculated for the next process input change signal that is calculated according to this method. The model is expressed in velocity form.

Abstract: The present invention relates to a multi-step process for producing HAN that is free of ammonium nitrate. The process comprises the steps of: (a) stripping ammonia from an ammonia-containing, aqueous hydroxylamine solution having a hydroxylamine concentration of at least 10% by weight based upon the weight of the hydroxylamine solution, by contacting the ammonia-containing hydroxylamine solution with a stripping agent selected from the group consisting of inert gases and steam to provide an ammonia-free, aqueous hydroxylamine solution, and (b) reacting the ammonia-free, aqueous hydroxylamine solution with aqueous nitric acid having an acid concentration of at least about 0.1%, preferably at least about 20%, based upon the weight of the aqueous nitric acid, to produce ammonium nitrate-free HAN. In another process embodiment of the invention, the above-described ammonia stripping step is not required, and the hydroxylamine concentration is at least about 0.

Abstract: A process for gas phase delignifying wood pulp comprising: contacting wood pulp in the first stage of pulp bleaching with chlorine dioxide-containing gas to delignify said wood pulp; wherein(a) said wood pulp has a consistency of at least about 15 percent;(b) said chlorine dioxide-containing gas contains less than about 3% by weight chlorine gas, based on the weight of chlorine dioxide in said gas; and(c) said contacting is conducted at a subatmospheric pressure from about 15 to about 750 mm Hg. This process reduces the formation of chloroform and significantly reduces the amounts of toxic by-products such as dioxin and other organic chlorides. These undesirable by-products, collectively identified as absorbable organic halides (AOX), require effluents from pulp bleaching processes to undergo expensive treatment methods to eliminate AOX's prior to discharges to sewers. The effluent discharge from this process generally has less than 2.0 kg adsorbed organic halides (AOX) per ton of wood pulp.

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 producing manganese dioxide and zinc metal comprising the steps of:(1) reacting a mixture of zinc oxide and manganese oxide with an aqueous chloric acid solution wherein the chloric acid is in molar excess of the manganese oxide in a reaction zone to form a reaction mixture in the zone comprising chlorine gas, a solid phase containing manganese dioxide, and a liquid phase containing zinc oxide, chloric acid and water; the concentration of chloric acid in the liquid phase is greater than about 1% by weight of the liquid phase upon leaving the reaction zone;(2) separating the chlorine gas from the solid phase and the liquid phase;(3) separating the solid phase containing manganese dioxide from the liquid phase containing zinc ions, chlorate ions, chloric acid, and water thereby forming a separated solid phase and a separated liquid phase;(4) subjecting the separated liquid phase to electrolysis in an electrochemical cell, thereby producing zinc metal at the cathode and oxygen at the anode;(5) remo

Abstract: 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.

Abstract: A process for producing manganese dioxide comprising the steps of:(1) reacting manganese oxide with a molar excess of an aqueous chloric acid solution in a reaction zone to form a reaction mixture in said zone comprising chlorine gas, a solid phase containing manganese dioxide, and a liquid phase containing chloric acid and water; the concentration of chloric acid in said liquid phase is greater than about 5% by weight of said liquid phase upon leaving the reaction zone;(2) separating said chlorine gas from said solid phase and said liquid phase;(3) separating said solid phase containing manganese dioxide from liquid phase containing chloric acid and water;(4) removing water from said separated liquid phase to concentrate said chloric acid in said separated liquid phase; and(5) returning said separated and concentrated liquid phase back to said reaction zone for further reaction with manganese oxide.

Abstract: 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.

Abstract: 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.