Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite
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 degre...
| Main Author: | |
|---|---|
| Format: | Journal Article |
| Published: |
2017
|
| Online Access: | http://hdl.handle.net/20.500.11937/54199 |
| _version_ | 1848759309393985536 |
|---|---|
| author | Jones, Franca |
| author_facet | Jones, Franca |
| author_sort | Jones, Franca |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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 Al3+ 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 |
| first_indexed | 2025-11-14T09:57:50Z |
| format | Journal Article |
| id | curtin-20.500.11937-54199 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:57:50Z |
| publishDate | 2017 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-541992017-09-13T16:09:43Z Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite Jones, Franca 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 Al3+ 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 2017 Journal Article http://hdl.handle.net/20.500.11937/54199 10.3390/min7060090 http://creativecommons.org/licenses/by/4.0/ fulltext |
| spellingShingle | Jones, Franca Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite |
| title | Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite |
| title_full | Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite |
| title_fullStr | Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite |
| title_full_unstemmed | Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite |
| title_short | Crystallization of Jarosite with Variable Al3+ Content: The Transition to Alunite |
| title_sort | crystallization of jarosite with variable al3+ content: the transition to alunite |
| url | http://hdl.handle.net/20.500.11937/54199 |