Chlorine

Schmittinger, Peter; Florkiewicz, T. F.; Curlin, L. Calvert; Lüke, Benno; Scannell, Robert; Navin, Thomas R.; Zelfel, Erich; Bartsch, R.

doi:10.1002/14356007.a06_399

Cited by 17 publications

(31 citation statements)

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“…Although the charge yields of both the chlor-alkali process, in which chlorine gas and sodium hydroxide are produced, and chlorate processes are quite high, ≥ 95%, , the fact that both chlorine gas and chlorate are bulk chemicals, produced in large quantities, means that losses of even a few percent are costly. The yearly electricity consumption in chlor-alkali production alone is about 150TWh, which makes it clear that improvements in energy efficiency of these processes could yield significant reductions in world energy consumption. The main side reaction in industrial electrolytic cells is the production of oxygen.…”

Section: Introductionmentioning

confidence: 86%

“…Chlorine gas and sodium chlorate are base chemicals, with yearly production rates of 50–60 million tonnes , and over three million tonnes, respectively. Chlorine gas is used in a wide variety of applications, including in production of construction materials such as polyvinyl chloride (PVC), in organic synthesis, in metallurgy, and in water treatment .…”

Section: Introductionmentioning

confidence: 99%

“…The electrolytic production of chlor-alkali and sodium chlorate is performed in either divided, for production of chlor-alkali, or undivided, for production of sodium chlorate, electrochemical cells using, for example, steel or activated Ni cathodes (Ni cathodes are only used in chlor-alkali production) and dimensionally stable anodes (DSA, dimensionally stable anode, is a trademark of Industrie De Nora S.p.A., Italy. ). , DSA are mixed ruthenium–titanium oxide (RTO) coatings of rutile RuO 2 and TiO 2 deposited on Ti. The usage of DSA to describe anodes in the present review is primarily used to refer to anodes of the typical industrial “Beer 2” (30% RuO 2 and 70% TiO 2 coated on Ti) formulation .…”

Section: Introductionmentioning

confidence: 99%

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Selectivity between Oxygen and Chlorine Evolution in the Chlor-Alkali and Chlorate Processes

2016

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Chlorine gas and sodium chlorate are two base chemicals produced through electrolysis of sodium chloride brine which find uses in many areas of industrial chemistry. Although the industrial production of these chemicals started over 100 years ago, there are still factors that limit the energy efficiencies of the processes. This review focuses on the unwanted production of oxygen gas, which decreases the charge yield by up to 5%. Understanding the factors that control the rate of oxygen production requires understanding of both chemical reactions occurring in the electrolyte, as well as surface reactions occurring on the anodes. The dominant anode material used in chlorate and chlor-alkali production is the dimensionally stable anode (DSA), Ti coated by a mixed oxide of RuO2 and TiO2. Although the selectivity for chlorine evolution on DSA is high, the fundamental reasons for this high selectivity are just now becoming elucidated. This review summarizes the research, since the early 1900s until today, concerning the selectivity between chlorine and oxygen evolution in chlorate and chlor-alkali production. It covers experimental as well as theoretical studies and highlights the relationships between process conditions, electrolyte composition, the material properties of the anode, and the selectivity for oxygen formation.

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Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Selectivity between Oxygen and Chlorine Evolution in the Chlor-Alkali and Chlorate Processes

2016

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“…However, the well-established “Deacon process” is based on the catalytic oxidation of HCl by O 2 using metal oxide catalysts such as CuO. 23,24 Interestingly, although there are no data on PuO 2 , other lanthanide and actinide oxides (U 3 O 8 , CeO 2 , and Ln 2 O 3 ) are known to be good catalysts for this reaction. 25−28 The thermodynamic equilibrium ratio p HCl / p Cl 2 can be calculated for likely relevant ranges of furnace conditions (see Table S2, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Thermal Processing of Chloride-Contaminated Plutonium Dioxide

et al. 2019

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Over 80 heat treatment experiments have been made on samples of chloride-contaminated plutonium dioxide retrieved from two packages in storage at Sellafield. These packages dated from 1974 and 1980 and were produced in a batch process by conversion of plutonium oxalate in a furnace at around 550 °C. The storage package contained a poly(vinyl chloride) (PVC) bag between the screw top inner and outer metal cans. Degradation of the PVC has led to adsorption of hydrogen chloride together with other atmospheric gases onto the PuO 2 surface. Analysis by caustic leaching and ion chromatography gave chloride contents of ∼2000 to >5000 ppm Cl (i.e., μgCl g –1 of the original sample). Although there are some subtle differences, in general, there is surprisingly good agreement in results from heat treatment experiments for all the samples from both cans. Mass loss on heating (LOH) plateaus at nearly 3 wt % above 700 °C, although samples that were long stored under an air atmosphere or preexposed to 95% relative humidity atmospheres, gave higher LOH up to ∼4 wt %. The majority of the mass loss is due to adsorbed water and other atmospheric gases rather than chloride. Heating volatilizes chloride only above ∼400 °C implying that simple physisorption of HCl is not the main cause of contamination. Interestingly, above 700 °C, >100% of the initial leachable chloride can be volatilized. Surface (leachable) chloride decreases quickly with heat treatment temperatures up to ∼600 °C but only slowly above this temperature. Storage in air atmosphere post-heat treatment apparently leads to a reequilibration as leachable chloride increases. The presence of a “nonleachable” form of chloride was thus inferred and subsequently confirmed in PuO 2 samples (pre- and post-heat treatment) that were fully dissolved and analyzed for the total chloride inventory. Reheating samples in either air or argon at temperatures up to the first heat treatment temperature did not volatilize significant amounts of additional chloride. With regard to a thermal stabilization process, heat treatment in flowing air at 800 °C with cooling and packaging under dry argon appears optimal, particularly, if thinner powder beds can be maintained. From electron microscopy, heat treatment appeared to have the most effect on degrading the square platelet particles compared to those with the trapezoidal morphology.

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“…In this reaction, the chlorine source is hydrogen chloride, which is oxidized according to the Deacon process. 2,12,13 Tetrachloroethene can also be converted into TCE (1) via hydrogenolysis with transition metal catalysts. 14 TrFE (3) has also been prepared using various approaches: 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) can be used as starting material in a vapor-phase reduction, 4a hydrodechlorination 15 or direct controlled-potential (bulk) electrolysis.…”

Section: Introductionmentioning

confidence: 99%