Chlorine Solutions in Molten Alkali Chlorides

Kolobov, A. Yu.; Хохлов, В. А.; Potapov, Alexei; Kochedykov, Victor A.

doi:10.1515/zna-2007-3-414

Cited by 2 publications

(1 citation statement)

References 3 publications

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“…It is well known that chlorine has good solubility in the liquid eutectic of FeCl 3 −NaCl. 24,25 Similarly, the gaseous chlorine probably also had good solubility in the liquid eutectic NiNa 0.33 Cl 2.33 . In stage 1, the chlorine passed through the sparse uncovered product layer and directly contacted the unreacted Ni core.…”

Section: Resultsmentioning

confidence: 99%

Hot Chlorination Corrosion of Metallic Nickel by Chlorine Catalyzed by Sodium Chloride

Chen

Shen

et al. 2020

ACS Omega

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Reducing chlorine corrosion to metals at high temperatures is a big problem for many industrial processes. Some high Ni alloys such as Hastelloy C-276 (Ni > 50 wt %) have been widely used for this purpose. Chlorine and chlorides often coexisted in many industrial processes at high temperatures, such as some industrial incinerators and metallurgical furnaces. Thus, a comprehensive experimental investigation regarding the effect of NaCl on the chlorination corrosion of metallic nickel powder by chlorine at a high temperature was performed. It was more convenient to investigate the intrinsic chlorination mechanisms and kinetics of metallic Ni if Ni powder was used instead of a Ni plate. It was found that there existed a critical chlorination temperature of 450 °C for relative safe use of Ni-based alloy in the presence NaCl. The Ni chlorination in the presence of NaCl was increased with increasing temperature and reached a maximum of 97% at 700 °C, which was about 21% higher than that in the absence of NaCl. An anhydrous NiCl 2 was initially formed at about 700 °C during the chlorination process and then immediately reacted with NaCl to form a novel eutectic complex with a flaky shape, a melting point of 585 °C, and a simplified molecular formula of NiNa 0.33 Cl 2.33 based on X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electronic microscopy (SEM), and chemical analysis with inductively coupled plasma atomic emission spectroscopy (ICP-AES). As a result, only the complex of NiNa 0.33 Cl 2.33 and NaCl was left in the chlorinated product. At 700 °C, the chlorinated product evaporated only in the form of complex NiNa 0.33 Cl 2.33 instead of individual NiCl 2 or NaCl. The chlorination mechanisms of metallic Ni at a high temperature, for example, 700 °C, in the presence of NaCl were as follows. Step 1: Formation of initial chlorinated solid product NiCl 2 (mp 1001 °C) at a high temperature; step 2: The NiCl 2 reacted with solid additive NaCl (mp 801 °C) to form a final liquid product NiNa 0.33 Cl 2.33 (mp 585 °C); step 3: External Cl 2 (g) was dissolved in the liquid product layer; step 4: The chlorine dissolved in the liquid product of NiNa 0.33 Cl 2.33 reacted with the unreacted Ni core. The external Cl 2 (g) passed through the liquid product NiNa 0.33 Cl 2.33 layer faster than the solid product NiCl 2 layer formed in the absence of NaCl. This resulted in 21% more chlorination corrosion of metallic Ni powder with NaCl addition than that without NaCl addition.

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Section: Resultsmentioning

confidence: 99%

Hot Chlorination Corrosion of Metallic Nickel by Chlorine Catalyzed by Sodium Chloride

Chen

Shen

et al. 2020

ACS Omega

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Preparation of dilute solutions of rare earth metal trichlorides by chlorination of their oxides in a molten NaCl-KCl equimolar mixture

Kolobov,

Potapov,

Khokhlov

2024

Rasplavy

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The article is devoted to the study and thermodynamic justification of the method for obtaining dilute solutions of rare earth metal trichlorides by chlorination of their oxides in a molten equimolar mixture of NaCl – KCl. And the effectiveness of this method is demonstrated by the example of lanthanum (III) and neodymium (III) oxides. Gibbs free energy of the reactions of La2O3 and Nd2O3 chlorination by different chlorinating agents has been calculated. The interaction of lanthanum (III) and neodymium (III) oxides in the molten equimolar mixture NaCl – KCl depending on the chlorination time and the material of reaction vessel (beryllium oxide and glass-carbon) has been studied experimentally. The results of thermodynamic modelling of the chlorination reactions of La2O3 and Nd2O3 by gaseous chlorine in this salt melt are presented. In the case of using a molten equimolar mixture of NaCl – KCl, a significant shift of the Gibbs energy to the negative region is observed compared with chlorination without the use of a salt medium. The effectiveness of chlorine as a chlorinating agent in the melt is based on the fact that in liquid NaCl-KCl Ln3+ ions form complexes with very small activity coefficient. The removal of synthesized lanthanum trichloride from the chlorination reaction zone due to its solubility in a low-viscosity NaCl-KCl melt has a beneficial effect on the rate of its flow. It has been shown that the formation of rare earth metal trichlorides occurs through the formation of LaOCl and NdOCl oxychlorides. The advantages of the proposed method of chlorination of rare earth metal oxides (REM) in the synthesis of solutions of their trichlorides in molten salts are shown.

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Chlorine Solutions in Molten Alkali Chlorides

Cited by 2 publications

References 3 publications

Hot Chlorination Corrosion of Metallic Nickel by Chlorine Catalyzed by Sodium Chloride

Hot Chlorination Corrosion of Metallic Nickel by Chlorine Catalyzed by Sodium Chloride

Preparation of dilute solutions of rare earth metal trichlorides by chlorination of their oxides in a molten NaCl-KCl equimolar mixture

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