Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations
Spodumene concentrate from the Pilbara region in Western Australia was characterized by X-ray diffraction (XRD), Scanning Electron Microscope Energy Dispersive Spectroscopy (SEM-EDS) and Mineral Liberation Analysis (MLA) to identify and quantify major minerals in the concentrate. Particle diameters...
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| author | Allen Yushark Fosu Ndue Kanari Danièle Bartier Harrison Hodge James Vaughan Alexandre Chagnes |
| author_facet | Allen Yushark Fosu Ndue Kanari Danièle Bartier Harrison Hodge James Vaughan Alexandre Chagnes |
| author_sort | Allen Yushark Fosu |
| collection | DOAJ |
| description | Spodumene concentrate from the Pilbara region in Western Australia was characterized by X-ray diffraction (XRD), Scanning Electron Microscope Energy Dispersive Spectroscopy (SEM-EDS) and Mineral Liberation Analysis (MLA) to identify and quantify major minerals in the concentrate. Particle diameters ranged from 10 to 200 microns and the degree of liberation of major minerals was found to be more than 90%. The thermal behavior of spodumene and the concentration of its polymorphs were studied by heat treatments in the range of 900 to 1050 °C. All three polymorphs of the mineral (α, γ and β) were identified. Full transformation of the α-phase was achieved at 975 °C and 1000 °C after 240 and 60 min treatments, respectively. SEM images of thermally treated concentrate revealed fracturing of spodumene grains, producing minor cracks initially which became more prominent with increasing temperature. Material disintegration, melting and agglomeration with gangue minerals were also observed at higher temperatures. The metastable γ-phase achieved a peak concentration of 23% after 120 min at 975 °C. We suggest 1050 °C to be the threshold temperature for the process where even a short residence time causes appreciable transformation, however, 1000 °C may be the ideal temperature for processing the concentrate due to the degree of material disintegration and α-phase transformation observed. The application of a first-order kinetic model yields kinetic parameters which fit the experimental data well. The resultant apparent activation energies of 655 and 731 kJ mol<sup>−1</sup> obtained for α- and γ-decay, respectively, confirm the strong temperature dependence for the spodumene polymorph transformations. |
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| id | doaj.art-c4ee7f58d95243609861ac3797d9595c |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T04:49:43Z |
| publishDate | 2021-12-01 |
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| series | Materials |
| spelling | doaj.art-c4ee7f58d95243609861ac3797d9595c2023-11-23T02:43:18ZengMDPI AGMaterials1996-19442021-12-011423742310.3390/ma14237423Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal TransformationsAllen Yushark Fosu0Ndue Kanari1Danièle Bartier2Harrison Hodge3James Vaughan4Alexandre Chagnes5Université de Lorraine, CNRS, GeoRessources, F-54000 Nancy, FranceUniversité de Lorraine, CNRS, GeoRessources, F-54000 Nancy, FranceUniversité de Lorraine, CNRS, GeoRessources, F-54000 Nancy, FranceSchool of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, AustraliaSchool of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, AustraliaUniversité de Lorraine, CNRS, GeoRessources, F-54000 Nancy, FranceSpodumene concentrate from the Pilbara region in Western Australia was characterized by X-ray diffraction (XRD), Scanning Electron Microscope Energy Dispersive Spectroscopy (SEM-EDS) and Mineral Liberation Analysis (MLA) to identify and quantify major minerals in the concentrate. Particle diameters ranged from 10 to 200 microns and the degree of liberation of major minerals was found to be more than 90%. The thermal behavior of spodumene and the concentration of its polymorphs were studied by heat treatments in the range of 900 to 1050 °C. All three polymorphs of the mineral (α, γ and β) were identified. Full transformation of the α-phase was achieved at 975 °C and 1000 °C after 240 and 60 min treatments, respectively. SEM images of thermally treated concentrate revealed fracturing of spodumene grains, producing minor cracks initially which became more prominent with increasing temperature. Material disintegration, melting and agglomeration with gangue minerals were also observed at higher temperatures. The metastable γ-phase achieved a peak concentration of 23% after 120 min at 975 °C. We suggest 1050 °C to be the threshold temperature for the process where even a short residence time causes appreciable transformation, however, 1000 °C may be the ideal temperature for processing the concentrate due to the degree of material disintegration and α-phase transformation observed. The application of a first-order kinetic model yields kinetic parameters which fit the experimental data well. The resultant apparent activation energies of 655 and 731 kJ mol<sup>−1</sup> obtained for α- and γ-decay, respectively, confirm the strong temperature dependence for the spodumene polymorph transformations.https://www.mdpi.com/1996-1944/14/23/7423spodumene concentratethermal transformationactivation energyfirst-order kineticsmorphological changesphysicochemical properties |
| spellingShingle | Allen Yushark Fosu Ndue Kanari Danièle Bartier Harrison Hodge James Vaughan Alexandre Chagnes Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations Materials spodumene concentrate thermal transformation activation energy first-order kinetics morphological changes physicochemical properties |
| title | Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations |
| title_full | Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations |
| title_fullStr | Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations |
| title_full_unstemmed | Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations |
| title_short | Physico-Chemical Characteristics of Spodumene Concentrate and Its Thermal Transformations |
| title_sort | physico chemical characteristics of spodumene concentrate and its thermal transformations |
| topic | spodumene concentrate thermal transformation activation energy first-order kinetics morphological changes physicochemical properties |
| url | https://www.mdpi.com/1996-1944/14/23/7423 |
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