Showing papers on "Sodium chlorate published in 1998"

Method for producing chlorine dioxide by activating an impregnated zeolite crystal mixture, and mixtures for performing such method

Abstract: A method for producing chlorine dioxide by activating a mixture of impregnated zeolite crystals, the mixture itself, and a method for regenerating the mixture after chlorine dioxide production. The activation is accomplished by causing water or a moisture-containing gas (e.g., air including water vapor) to flow through the mixture or otherwise exposing the mixture to such fluid, or by exposing the mixture to liquid hydrogen peroxide, liquid sulfuric acid, ferric chloride solution, or sodium chlorate solution. The mixture can include sodium chlorite-impregnated zeolite crystals and zeolite crystals impregnated with ferric chloride, ferric sulfate, or both, and optionally also zeolite crystals impregnated with calcium chloride. Alternatively, the mixture includes sodium chlorate-impregnated zeolite crystals, sulfuric acid-impregnated zeolite crystals, zeolite crystals impregnated with one or more of calcium chloride (or another deliquescent or water absorbing and retaining substance, such as one or more of ferric chloride and ferric sulfate), and an oxidizer (such as hydrogen peroxide, sodium metabisulfite, or sodium bisulfite). The oxidizer reacts (in the presence of water absorbed by the deliquescent or water absorbing substance) to release another substance which in turn reacts with one or more of the other impregnating substances to produce chlorine dioxide. The chlorine dioxide release rate can be controlled in any of several ways, including by selecting the concentration and amount of activating liquid, or using zeolite having a selected weight ratio of one or more impregnating substance to zeolite.

Influence of H2O2 on a chloride‐dependent reaction path to chlorine dioxide

Abstract: Reaction paths governing chlorine dioxide formation from solutions of sodium chlorate, sulfuric acid, hydrogen peroxide and sodium chloride at 25°C were examined. Chlorine dioxide was formed by two paths: the reduction of chlorate by hydrogen peroxide and the reduction of chlorate by chloride. At conditions of this study, the rate of the chloride-chlorate path predominated and was enhanced by hydrogen peroxide, reaching an upper limit as hydrogen peroxide concentration was increased. A mechanism was proposed that explains the observed behavior. It is based on existing theory, but includes a new step: the rapid reaction of hydrogen peroxide with an intermediate, Cl2O2. It was shown also that chloride was not required to sustain chlorine dioxide formation in the hydrogen peroxide-chlorate path.

Process for producing solid chlorine dioxide

Abstract: A process for preparing ClO2 solid includes reaction of diluted sulfuric acid solution with methanol and solid sodium chlorate in reaction tower in the presence of NaCl as catalyst to obtain ClO2 gas, cooling in cooler, adsorbing ClO2 by water, regulating pH to 8-9, spraying the ClO2 solution dissolved in water to absorbent, stirring and tabletting, and features convenient preparation and transportation, high purity and high sterilization effect

Method for producing high purity chlorine dioxide food additives

Abstract: The production method of high-purity chlorinedioxide food additive belongs to a method for producing chlorinedioxide disinfectant preservative and fresh-keeping agent which can be used as additive for food, and mainly is characterized by that it uses sodium chlorate, oxalic acid and sulfuric acid as raw materials to produce chlorinedioxide gas, then said gas is cleaned by using 5-15% urea solution, and then absorbed by alkaline stabilizing agent so as to obtain the high-purity, high-concentration and high-stability stabilized chlorinedioxide solution. The composition of said stabilizing agentconsists of sodium carbonate, hydrogen peroxide, sodium dodecasulfonic benzoate and 8-quinolinol according to the weight ratio of 1 : 0.2-0.9 : 0.002-0.01 : 0.0002-0.001.

Purifying metal halide from organic and carbonaceous impurities

Abstract: A method of purifying metal halides from organic and carbonaceous impurities involves heating a mixture of the solid halide with a solid additive which includes a halogen-oxygen bond and which dissociates at below the metal halide melting temperature. Preferably, the additive is a halogen-oxygen acid (or its alkali metal salt or anhydride) or a halogen oxide of the halide in the metal halide. Chlorides and bromides may also be purified using easily decomposable alkali salts of chlorine-oxygen acids and bromine-oxygen acids, e.g. caesium chloride may be purified using caesium perchlorate (CsClO4) at 250 deg C and sodium chloride may be purified using sodium chlorate (NaClO3) or sodium perchlorate (NaClO4) at 482 deg C. The amount of additive is unimportant. The purified metal halide may be transferred directly, without cooling, into a melting crucible for production of large crystals by the Bridgeman-Stockbarger or Czochralski process.