![]() ![]() 3, 5 This process was originally developed for recovering uranium from used nuclear fuel. 6– 11 The concept underlying the process can also be used as a decontamination option when radioactive contaminants exist at levels deeper than the surface oxide layers. 4, 5Īn electrorefining process using molten salt has been developed to treat and recycle nuclear materials in used nuclear fuel. 3 In addition, decontaminating the waste can change waste categories from intermediate level waste to low level waste. Such radioactive waste must be decontaminated to reduce the volume of final waste as well as to meet the waste acceptance criteria of the final repository. In particular, radioactive isotopes are distributed in the volume of the reactor internals and pressure vessels made of steel alloys because of neutron activation reactions. 1, 2 Structural components containing these metallic elements are activated in volume or contaminated on surfaces. Radioactive metallic waste produced from nuclear power plants commonly contains Cr, Fe, and Ni as alloying constituents and Co as an impurity. The findings of this study will be directly used for designing a decontamination process to produce acceptable waste forms and reduce waste volume. The obtained reaction properties were used in the numerical modeling of the ECE reaction in a Ni and Co binary system to reproduce the experimental results of CV, revealing the presence of chemical reaction. In particular, the redox reaction of Cr(III)/Cr(II) was investigated by chronoabsorptometry to obtain its formal potential, the number of electrons, and the diffusion coefficient of Cr(II). UV–vis-NIR absorption spectroscopy of the metallic constituents was performed to derive molar absorption coefficients and molecular structures in molten salt media. The order of the diffusion coefficients was 10 –5 cm 2 s −1, which agrees with the existing data and the standard rate constants showed similar values with the order of 10 –3 cm s −1 between experimental correlations and numerical fitting. Cyclic voltammetry combined with numerical fitting was used to obtain the formal potentials, standard rate constants, and diffusion coefficients of redox reactions, Cr(II)/Cr, Fe(II)/Fe(0), Co(II)/Co(0), and Ni(II)/Ni(0), in LiCl-KCl at 773 K. JT Baker.This study examines the thermodynamic, kinetic, and spectroscopic behaviors of Cr, Fe, Co, and Ni to lay the foundation to develop an electrochemical decontamination process for radioactive metallic wastes. Chromium (VI) compounds are carcinogenic to humans (Group 1). There is sufficient evidence in experimental animals for the carcinogenicity of chromium (VI) compounds. ![]() Also positive associations have been observed between exposure to Chromium (VI) compounds and cancer of the nose and nasal sinuses. Chromium (VI) compounds cause cancer of the lung. There is sufficient evidence in humans for the carcinogenicity of chromium (VI) compounds. Lyon: International Agency for Research on Cancer. Volume 100C: Arsenic, Metals, Fibres, and Dusts (PDF). "Structure cristalline de la forme 'basse temperature' du sulfate de potassium K 2SO 4-beta" (Crystal structure of the "low temperature" β-form of potassium sulfate) Bulletin de la Société Chimique de France 1968, vol. ^ a b Gerd Anger, Jost Halstenberg, Klaus Hochgeschwender, Christoph Scherhag, Ulrich Korallus, Herbert Knopf, Peter Schmidt, Manfred Ohlinger, "Chromium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.Human exposure further encompasses impaired fertility, heritable genetic damage and harm to unborn children. The compound is also corrosive and exposure may produce severe eye damage or blindness. Safety Īs with other Cr(VI) compounds, potassium chromate is carcinogenic. It occurs very rarely and until now is known from only few localities on Atacama Desert. Tarapacaite is the natural, mineral form of potassium chromate. It is also used as an indicator in precipitation titrations with silver nitrate and sodium chloride (they can be used as standard as well as titrant for each other) as potassium chromate turns red in the presence of excess of silver ions. It is used in qualitative inorganic analysis, e.g. It is as an oxidizing agent in organic synthesis. Unlike the less expensive sodium salt, potassium salt is mainly used for laboratory work in situations where an anhydrous salt is required. When treated with lead(II) nitrate, it gives an orange-yellow precipitate, lead(II) chromate. In solution, the behavior of potassium and sodium dichromates are very similar. K 2 Cr 2 O 7 ( aq ) + 2 KOH ⟶ 2 K 2 CrO 4 + H 2 O It is prepared by treating potassium dichromate with potassium hydroxide: The environment about the tetrahedral CrO 4 2− center in β-K 2CrO 4. ![]()
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