THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT

The interaction of tungsten (VI) oxide and calcium tungstate with a molten eutectic mixture of calcium-sodium chlorides in the temperature range from 600 to 800 °С was investigated by the methods of isothermal saturation, mass spectrometry with inductively coupled plasma (ICP–MS) and X-ray phase ana...

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Дата:2023
Автори: Medvezhynska, Olha, Omel'chuk, Anatoliy, Shvaika, Irine, Shvayka, Igor, Proskurka, Lubov
Формат: Стаття
Мова:English
Опубліковано: V.I.Vernadsky Institute of General and Inorganic Chemistry 2023
Онлайн доступ:https://ucj.org.ua/index.php/journal/article/view/538
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Назва журналу:Ukrainian Chemistry Journal

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Ukrainian Chemistry Journal
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spelling oai:ojs2.1444248.nisspano.web.hosting-test.net:article-5382023-06-14T19:46:42Z THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT Medvezhynska, Olha Omel'chuk, Anatoliy Shvaika, Irine Shvayka, Igor Proskurka, Lubov oxygen-containing compounds of tungsten, chlorides of sodium, calcium, molten mixture, interaction. The interaction of tungsten (VI) oxide and calcium tungstate with a molten eutectic mixture of calcium-sodium chlorides in the temperature range from 600 to 800 °С was investigated by the methods of isothermal saturation, mass spectrometry with inductively coupled plasma (ICP–MS) and X-ray phase analysis. It was noted that the solubility of both tungsten trioxide and calcium tungstate depends to a large extent on temperature. Thus, in the temperature range from 600 to 700 °C, the equilibrium concentration of tungsten increases by an average of 1.7 times, and in the range from 700 to 800 °C, its values increase by 3.9 times. Based on the results obtained by inductively coupled plasma mass spectrometry, it was found that the equilibrium content of tungsten (in the calculation of pure metal) in the molten eutectic mixture of sodium and calcium chlorides both in contact with tungsten trioxide and in contact with calcium tungstate at different temperatures within the error of definition has approximately the same values. The obtained results indicate in favor of the fact that the dissolution of tungsten trioxide in the molten mixture of sodium and calcium chlorides proceeds through the stage of formation of calcium tungstate. It is possible that sodium tungstate may be formed in this case, but no direct evidence of this has been found. At temperatures higher than 750 °C, almost all of the loaded tungsten trioxide turns into calcium tungstate. This gives grounds for asserting that in the molten salt phase tungsten is mainly in the form of calcium tungstate. The obtained results give reason to consi­der that the interaction of the mentioned oxy­gen-containing compounds of tungsten produces homogeneous salt phases of the ternary system CaCl2–NaCl–CaWO4, the content of which calcium tungstate in the temperature range of 700÷800 °С is satisfactorily described by the dependence ln S = 8.331 – 14057/T. V.I.Vernadsky Institute of General and Inorganic Chemistry 2023-04-28 Article Article Physical chemistry Физическая xимия Фізична xімія application/pdf https://ucj.org.ua/index.php/journal/article/view/538 10.33609/2708-129X.89.03.2023.25-36 Ukrainian Chemistry Journal; Vol. 89 No. 3 (2023): Ukrainian Chemistry Journal; 25-36 Украинский химический журнал; Том 89 № 3 (2023): Ukrainian Chemistry Journal; 25-36 Український хімічний журнал; Том 89 № 3 (2023): Український хімічний журнал; 25-36 2708-129X 2708-1281 en https://ucj.org.ua/index.php/journal/article/view/538/273
institution Ukrainian Chemistry Journal
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datestamp_date 2023-06-14T19:46:42Z
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language English
topic_facet oxygen-containing compounds of tungsten
chlorides of sodium
calcium
molten mixture
interaction.
format Article
author Medvezhynska, Olha
Omel'chuk, Anatoliy
Shvaika, Irine
Shvayka, Igor
Proskurka, Lubov
spellingShingle Medvezhynska, Olha
Omel'chuk, Anatoliy
Shvaika, Irine
Shvayka, Igor
Proskurka, Lubov
THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT
author_facet Medvezhynska, Olha
Omel'chuk, Anatoliy
Shvaika, Irine
Shvayka, Igor
Proskurka, Lubov
author_sort Medvezhynska, Olha
title THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT
title_short THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT
title_full THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT
title_fullStr THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT
title_full_unstemmed THE INTERACTION OF TUNGSTEN (VI) OXIDE AND CALCIUM TUNGSTATE IN THE CaCl2–NaCl EUTECTIC MELT
title_sort interaction of tungsten (vi) oxide and calcium tungstate in the cacl2–nacl eutectic melt
description The interaction of tungsten (VI) oxide and calcium tungstate with a molten eutectic mixture of calcium-sodium chlorides in the temperature range from 600 to 800 °С was investigated by the methods of isothermal saturation, mass spectrometry with inductively coupled plasma (ICP–MS) and X-ray phase analysis. It was noted that the solubility of both tungsten trioxide and calcium tungstate depends to a large extent on temperature. Thus, in the temperature range from 600 to 700 °C, the equilibrium concentration of tungsten increases by an average of 1.7 times, and in the range from 700 to 800 °C, its values increase by 3.9 times. Based on the results obtained by inductively coupled plasma mass spectrometry, it was found that the equilibrium content of tungsten (in the calculation of pure metal) in the molten eutectic mixture of sodium and calcium chlorides both in contact with tungsten trioxide and in contact with calcium tungstate at different temperatures within the error of definition has approximately the same values. The obtained results indicate in favor of the fact that the dissolution of tungsten trioxide in the molten mixture of sodium and calcium chlorides proceeds through the stage of formation of calcium tungstate. It is possible that sodium tungstate may be formed in this case, but no direct evidence of this has been found. At temperatures higher than 750 °C, almost all of the loaded tungsten trioxide turns into calcium tungstate. This gives grounds for asserting that in the molten salt phase tungsten is mainly in the form of calcium tungstate. The obtained results give reason to consi­der that the interaction of the mentioned oxy­gen-containing compounds of tungsten produces homogeneous salt phases of the ternary system CaCl2–NaCl–CaWO4, the content of which calcium tungstate in the temperature range of 700÷800 °С is satisfactorily described by the dependence ln S = 8.331 – 14057/T.
publisher V.I.Vernadsky Institute of General and Inorganic Chemistry
publishDate 2023
url https://ucj.org.ua/index.php/journal/article/view/538
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