Título: | THERMODYNAMICS SIMULATIONS AND KINETICS MODELING OF MGSO4.7H2O THERMAL DECOMPOSITION | ||||||||||||
Autor: |
BRUNO MUNIZ E SOUZA |
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Colaborador(es): |
EDUARDO DE ALBUQUERQUE BROCCHI - Orientador RODRIGO FERNANDES MAGALHAES DE SOUZA - Coorientador |
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Catalogação: | 18/SET/2023 | Língua(s): | ENGLISH - UNITED STATES |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=63963&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=63963&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.63963 | ||||||||||||
Resumo: | |||||||||||||
Magnesium sulfate is present in several industrial and mining wastes.
It and its derivatives could be reused in various industrial areas, ceasing to
be a waste to become part of a process. Its oxide, MgO, can be used in
some functions, as a pH regulator, depending on its reactivity. Due to this,
its formation must occur at temperatures below the decomposition
temperatures of MgSO4. Therefore, this work evaluated aspects of the
decomposition of MgSO4 through two articles. Article 1 (Thermodynamics
Simulations and Kinetics Modeling of the Thermal Decomposition of
MgSO4.7H2O: Part 1 – Reducing Agent Effect), evaluated the kinetic effect
of using carbon, through four different reducing agents, on the thermal
decomposition of MgSO4.7H2O, while article 2 (Thermodynamics
Simulations and Kinetics Modeling of the Thermal Decomposition of
MgSO4.7H2O: Part 2 – Hydration Effect) analyzed the influences of the
heating rate of the tests and the degree of hydration of the magnesium
sulfate used. The thermogravimetric tests carried out throughout these
articles used samples with a mass of approximately 10 mg of the mixture
(sulfate + reducing agent) and these mixtures had a stoichiometric ratio of
1:1. The experiments carried out in article 1 used reducing agents, charcoal,
green coke, breeze coke, and graphite as reducing agents. In article 2, the
sulfates analyzed were anhydrous, monohydrate, and heptahydrate and the
heating rates used were 5 K.min(-1)
, 10 K.min(-1)
, 15 K.min(-1)
, and 20 K.min(-1).
All data obtained from thermogravimetric tests were processed through
mathematical modeling to obtain kinetic data. In article 1, the use of
reducing agents proved efficient, reducing the activation energy of
magnesium sulfate decomposition from 22.731 kJ.mol(-1)
(pure sulfate) to
340.391 kJ.mol(-1)
(green coke), 196.120 kJ.mol(-1)
(graphite), 191,100 kJ.mol(-1)
(coke breeze) and 162,302 kJ.mol(-1)
(charcoal). In article 2, the heating rate
was not shown to be a determining factor for the decomposition of MgSO4,
in relation to the hydration of magnesium sulfate, the results indicated that
a small portion of H2O in the system can positively influence the
decomposition since the average Ea values were 404.5 KJ.mol(-1)
(mono),
407 KJ.mol(-1)
(anhydrous) and 433.3 KJ.mol(-1)
(hepta).
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