Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching

Heat-treatment of spodumene concentrate at 1323 K (1050 °C) for 30 min in a rotary kiln yielded a successful decrepitation. Particle size decreased from 2 cm to less than 425 µm for 80% of the initial mass. X-ray analysis of both fractions did not reveal the presence of α-spodumene or γ-spodumene. T...

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Main Authors: Colin Dessemond, Gervais Soucy, Jean-Philippe Harvey, Philippe Ouzilleau
Format: Article
Language:English
Published: MDPI AG 2020-06-01
Series:Minerals
Subjects:
Online Access:https://www.mdpi.com/2075-163X/10/6/519
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author Colin Dessemond
Gervais Soucy
Jean-Philippe Harvey
Philippe Ouzilleau
author_facet Colin Dessemond
Gervais Soucy
Jean-Philippe Harvey
Philippe Ouzilleau
author_sort Colin Dessemond
collection DOAJ
description Heat-treatment of spodumene concentrate at 1323 K (1050 °C) for 30 min in a rotary kiln yielded a successful decrepitation. Particle size decreased from 2 cm to less than 425 µm for 80% of the initial mass. X-ray analysis of both fractions did not reveal the presence of α-spodumene or γ-spodumene. The coarse fraction was ground to less than 425 µm with minimal mechanical energy and mixed with the finer fraction to perform lithium extraction. The lithium extraction efficiency reached 98 wt% without the need for flotation. Some aspects of the thermodynamic behavior of the spodumene system were assessed. Results show that metastable γ-spodumene may hinder the formation of β-spodumene at lower heat treatment temperatures. Some heat-treated samples presented non-negligible γ-spodumene content and lithium extraction efficiency decreases as the γ content increases. Finally, the assumed irreversibility of the transformations was studied by analyzing heat-treated samples following long controlled-storage periods. The results show that concentrate composition is not static over the studied time. This suggests that the β formation is not as irreversible as claimed. It is recommended to avoid long periods between heat-treatment and extraction to avoid the slow conversion of β-spodumene to other allotropes, which are less susceptible to lithium extraction.
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spelling doaj.art-c0224f59549a4614a5055b556e1c3bed2023-11-20T02:57:46ZengMDPI AGMinerals2075-163X2020-06-0110651910.3390/min10060519Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid LeachingColin Dessemond0Gervais Soucy1Jean-Philippe Harvey2Philippe Ouzilleau3Département de Génie Chimique et Biotechnologique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaDépartement de Génie Chimique et Biotechnologique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaPolytechnique Montréal, Université de Montréal, Montréal, QC H3T 1J4, CanadaDépartement de Génie Chimique et Biotechnologique, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, CanadaHeat-treatment of spodumene concentrate at 1323 K (1050 °C) for 30 min in a rotary kiln yielded a successful decrepitation. Particle size decreased from 2 cm to less than 425 µm for 80% of the initial mass. X-ray analysis of both fractions did not reveal the presence of α-spodumene or γ-spodumene. The coarse fraction was ground to less than 425 µm with minimal mechanical energy and mixed with the finer fraction to perform lithium extraction. The lithium extraction efficiency reached 98 wt% without the need for flotation. Some aspects of the thermodynamic behavior of the spodumene system were assessed. Results show that metastable γ-spodumene may hinder the formation of β-spodumene at lower heat treatment temperatures. Some heat-treated samples presented non-negligible γ-spodumene content and lithium extraction efficiency decreases as the γ content increases. Finally, the assumed irreversibility of the transformations was studied by analyzing heat-treated samples following long controlled-storage periods. The results show that concentrate composition is not static over the studied time. This suggests that the β formation is not as irreversible as claimed. It is recommended to avoid long periods between heat-treatment and extraction to avoid the slow conversion of β-spodumene to other allotropes, which are less susceptible to lithium extraction.https://www.mdpi.com/2075-163X/10/6/519spodumene heat treatmentphase transitionsthermodynamic phase diagramacid leaching lithium extraction
spellingShingle Colin Dessemond
Gervais Soucy
Jean-Philippe Harvey
Philippe Ouzilleau
Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching
Minerals
spodumene heat treatment
phase transitions
thermodynamic phase diagram
acid leaching lithium extraction
title Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching
title_full Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching
title_fullStr Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching
title_full_unstemmed Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching
title_short Phase Transitions in the α–γ–β Spodumene Thermodynamic System and Impact of γ-Spodumene on the Efficiency of Lithium Extraction by Acid Leaching
title_sort phase transitions in the α γ β spodumene thermodynamic system and impact of γ spodumene on the efficiency of lithium extraction by acid leaching
topic spodumene heat treatment
phase transitions
thermodynamic phase diagram
acid leaching lithium extraction
url https://www.mdpi.com/2075-163X/10/6/519
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