Showing papers on "Sodium chlorate published in 1993"

Morphology and growth kinetics of large sodium chlorate crystals grown in the presence and absence of sodium dithionate impurity

Abstract: A study has been made of the influence of variations in cooling rate (supersaturation) and impurity content of the changes in morphology (habit and surface features) of sodium chlorate crystals grown from aqueous solution The habit was found to vary from pure cubic at high cooling rates to cuboid with relatively small {110} and (111), (111), (111), and (111) faces at low cooling rates Optical examination of the as grown surfaces of the resulting crystals revealed the presence of growth hillocks and surface features characteristic of dislocation-associated growth mechanisms This speculation was supported by the distribution of dislocations in the various growth sectors, identified by Lang topography

Kinetics of hydrogen peroxide-chlorate reaction in the formation of chlorine dioxide

Abstract: This paper reports and discusses an experimental prrogram that investigates chlorine dioxide formation by reduction of sodium chlorate with hydrogen peroxide in aqueous sulfuric acid. The rate of reaction was studied in both batch and well-mixed reactors over ranges of temperature and reactant concentrations which bracket conditions of commercial interest. The rate data were correlated by a power law model in which an acidity function H - was used to characterize the acidity of sulfuric acid.

Functions of barium peroxide in sodium chlorate chemical oxygen generators

Abstract: Catalyzed decomposition of NaClO 3 and the effect of BaO 2 and Ba(OH) 2 -H 2 O on the decomposition are studied using thermal gravimetric analysis and differential thermal analysis. BaO 2 and Ba(OH) 2 -H 2 O are moderately active catalyst when used alone and inhibitors when used with the more active catalyst cobalt oxide for NaClO 3 decomposition. The smoothing effect of BaO 2 on NaClO 3 decomposition is explained, and the mechanism of chlorine suppressing during NaClO 3 decomposition is discussed.

Sodium Salts of Chlorine Oxyacid Anions, Cl(+7), Perchlorate, XPS Comparison Spectra

Abstract: High quality sodium chlorate has been analyzed as part of a series of chlorine oxyacid salts, chlorite to perchlorate. The spectra include survey and high resolution scans over the major photopeaks, the sodium Auger transitions and the valence band of the compound. Spectra for this compound were collected with the magnesium x‐ray source. Several literature references are provided as additional sources of XPS data and description of the chemistry of chlorine oxyacid anions.

Chlorine dioxide generation for a zero discharge pulp mill

Abstract: Chlorine dioxide for a cellulose pulp mill bleach plant is produced by concentrating (evaporating) liquid effluents from the bleach plant to a concentration level high enough for incineration, incinerating the concentrated effluents to produce an ash, chemically reacting at least a part of the ash to produce chlorate, and using the chlorate in the manufacture of chlorine dioxide. The ash is purified to produce sodium chloride and the sodium chloride is reacted with oxygen and external energy to produce sodium chlorate. The chlorate is then used in the manufacture of chlorine dioxide. Sulfates produced are used to manufacture acid and/or caustic, and heavy metal hydroxides are disposed of. A part of the ash may be used directly in chlorine dioxide manufacture. At least some of the salt from chlorate manufacture may be fed to the chemical recovery loop, including a recovery boiler, in the pulp mill. Evaporated gases may be returned to the pulp mill and bleach plant.

Catalytic effects of nonoxide metal compounds on the thermal decomposition of sodium chlorate

Abstract: Thermal decompositions of NaClO 3 in the presence of various non-oxide metal compounds were studied using thermogravimetric analysis. The non-oxide additives show catalytic activities similar to those of the corresponding metal oxides. The correlations between electron configurations and catalytic activities are discussed. It is found that metal cations with partially filled d orbitals are all active catalyst. Metal cations with d 0 configurations are moderately active. Metal cations with d 10 or noble gas configurations have the lowest activity

Process for the crystallisation of sodium chlorate and solid granular mass based on sodium chlorate

Abstract: Process for the crystallization of sodium chlorate, according to which a supersaturated aqueous solution of sodium chlorate (14) is circulated from bottom to top through a bed of crystals (6) so as to fluidize it. Granular solid mass based on sodium chlorate, comprising granules in the form of balls substantially without sharp edges.

Membrane Cell Operation

Abstract: The voltage requirements of a membrane-divided cell are decreased by operating the cell with a catholyte temperature significantly in excess of the anolyte temperature, generally at least 10°C greater and preferably at least 20°C greater. The invention is particularly useful in an electrochemical acidification process whereby aqueous sodium chlorate and sodium sesquisulfate solution is acidified for use in a chlorine dioxide generating process and aqueous sodium hydroxide is produced as a by-product.

Growth and habit modification of sodium chlorate crystals

Abstract: Single crystals of sodium chlorate were grown in the presence of selective impurities. The morphology of these crystals changed completely from cubic to tetrahedral form. Experiments were performed in the presence of different concentrations of impurities to ascertain their role in modifying the habit of these crystals. The presence of impurity in the solution was found to affect the habit of the crystals, although it does not appear to enter into the lattice.