Thermochemistry of jarosite-alunite and natrojarosite-natroalunite solid solutions

Drouet, Christophe; Pass, Katrina L.; Baron, Dirk; Draucker, Sara; Navrotsky, Alexandra

doi:10.1016/j.gca.2003.12.001

Cited by 63 publications

(59 citation statements)

References 20 publications

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“…The formula was determined by assuming the sulphate content and determining the number of moles of the K, Al, and Fe relative to sulphate from the ICP data. Finally, the hydronium, water and hydroxide content were determined by charge neutralization considerations as given by ( [14]. The calculated compositions are shown in Table 2.…”

Section: Elemental Analysismentioning

confidence: 99%

“…Alunite is isostructural with jarosite, where the Fe 3+ is replaced with Al 3+ [13][14][15][16][17]. Recently, it has also been found on Mars [18].…”

Section: Introductionmentioning

confidence: 99%

“…For this reason, synthetic samples are often used to determine relationships free from other substitutional interferances [13][14][15]. Alunite is also said to be found in nature with significant Fe substitution [13][14][15], although studies on natural K-alunite/jarosite samples are rare in the literature.…”

Section: Introductionmentioning

confidence: 99%

“…Other comprehensive investigations of the jarosite-alunite solid solution are from the group of Navrotsky [13,14]. These investigations mainly focus on the thermodynamics [14] of formation and in particular the difference between Na and K containing jarosites [13].…”

Section: Introductionmentioning

confidence: 99%

“…These investigations mainly focus on the thermodynamics [14] of formation and in particular the difference between Na and K containing jarosites [13]. There is a lack of information in these manuscripts on how the infrared spectroscopy or thermal behaviour alters for the entire solid solution from 0 to 1, but there is previously published infrared spectroscopy information on jarosite and alunite [9,15,27,28] looking at the formation of the Fe and Al end members of the jarosite family to determine their spectroscopic characteristics [9].…”

Section: Introductionmentioning

confidence: 99%

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Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite

Jones

2017

Minerals

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This study focused on the formation of the jarosite-alunite solid solution at relatively low temperature, 90 • C. It was found that the transition from jarosite to alunite results in significant changes in the powder X-ray diffraction pattern, the infrared spectrum and thermal behavior when the degree of substitution reached ≥50%. The initial Al/(Al + Fe) in solution, however, required to achieve these substitution levels in the solid is ≥90%. The morphology shows that the faceted jarosite form goes through an intergrown transition to a spherical morphology of pure alunite. This morphology has not been previously observed for alunite and most likely reflects the formation temperature. Rietveld analysis shows that the a lattice parameter obeys Vegard's Rule while the c lattice parameter behavior is more complex. Empirical modelling of the incorporation of Fe into alunite supports the general trends found in the X-ray diffraction data for the behaviour of the a-axis with Al/Fe content. The dehydration of the Al 3+ ion could be a significant contribution to the activation energy barrier to alunite formation as found for other minerals. Finally, dynamic light scattering showed that the nucleation behavior for jarosite and Fe-containing alunite are significantly different. Alunite appears to nucleate continuously rather than in a single nucleation event.

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Section: Elemental Analysismentioning

confidence: 99%

“…Alunite is isostructural with jarosite, where the Fe 3+ is replaced with Al 3+ [13][14][15][16][17]. Recently, it has also been found on Mars [18].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite

Jones

2017

Minerals

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Thermodynamic Properties of Polymorphs of Fluorosulfate Based Cathode Materials with Exchangeable Potassium Ions

et al. 2016

Self Cite

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FeSO F-based frameworks have recently emerged as attractive candidates for alkali insertion electrodes. Mainly owing to their rich crystal chemistry, they offer a variety of new host structures with different electrochemical performances and physical properties. In this paper we report the thermodynamic stability of two such K-based "FeSO F" host structures based on direct solution calorimetric measurements. KFeSO F has been reported to crystallize in two different polymorphic modifications-monoclinic and orthorhombic. The obtained enthalpies of formation from binary components (KF plus FeSO ) are negative for both polymorphs, indicating that they are thermodynamically stable at room temperature, which is very promising for the future exploration of sulfate based cathode materials. Our measurements show that the low-temperature monoclinic polymorph is enthalpically more stable than the orthorhombic phase by ≈10 kJ mol , which is consistent with the preferential formation of monoclinic KFeSO F at low temperature. Furthermore, observed phase transformations and difficulties in the synthesis process can be explained based on the obtained calorimetric results. The KMnSO F orthorhombic phase is more stable than both polymorphs of KFeSO F.

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Thermal expansion and decomposition of jarosite: a high-temperature neutron diffraction study

Zhao

Vogel

et al. 2009

Phys Chem Minerals

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The structure of deuterated jarosite, KFe3(S04)2(OD)6, was investigated using time-of-flight neutron diffraction up to its dehydroxylation temperature. Rietveld analysis reveals that with increasing temperature, its c dimension expands at a rate ~10 times larger than that for a. This anisotropy of thermal expansion is due to rapid increase in the thickness of the (001) On heating, the hydrogen bonds, 01···D-03, through which the (001) octahedral tetrahedral sheets are held together, become weakened, as reflected by increase in the D···01 distance and concomitant decrease in the 03-D distance with increasing temperature. On further heating to 575 K, jarosite starts to decompose into nanocrystalline yavapaiite and hematite (as well as water vapor), a direct result of the breaking of the hydrogen bonds that hold the jarosite structure together.

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Thermochemistry of jarosite-alunite and natrojarosite-natroalunite solid solutions

Cited by 63 publications

References 20 publications

Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite

Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite

Thermodynamic Properties of Polymorphs of Fluorosulfate Based Cathode Materials with Exchangeable Potassium Ions

Thermal expansion and decomposition of jarosite: a high-temperature neutron diffraction study

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