Enthalpy of Formation of Alunite and Natroalunite (According Calorimetric Data)статьяИсследовательская статья
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Дата последнего поиска статьи во внешних источниках: 16 июня 2022 г.
Аннотация:A sample of natural alunite of the composition K0.6Na0.4Al3(SO4)2(OH)6 was studied by powderX-ray diffraction, infrared spectroscopy, electron microprobe, and thermal analysis. The enthalpy of formationof the alunite from elements ΔfH0(298.15 K) = −5149 ± 13 kJ/mol was determined by the method of meltsolution calorimetry, using a Setaram (France) Calvet microcalorimeter. The calculated enthalpies andGibbs energies of formation of the end members of the series alunite KAl3(SO4)2(OH)6 to natroaluniteNaAl3(SO4)2(OH)6 are − 5164 ± 13 and − 4651 ± 13 kJ/mol, respectively, for alunite and − 5127 ± 13 and− 4615 ± 13 kJ/mol, respectively, for natroalunite.