Pressure leach of β-spodumene with carbonic acid: Weak acid process for extraction of lithium

Mahmoud F. Alhadad; Hans C. Oskierski; Johannes Chischi; Gamini Senanayake; Bernhard Schulz; Alexandra A. Suvorova; Sarah E. M. Gain; Bogdan Z. Dlugogorski

doi:10.1016/j.mineng.2023.108398

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Pressure leach of β-spodumene with carbonic acid: Weak acid process for extraction of lithium

Journal article

Open access

Peer reviewed

Pressure leach of β-spodumene with carbonic acid: Weak acid process for extraction of lithium

Mahmoud F. Alhadad, Hans C. Oskierski, Johannes Chischi, Gamini Senanayake, Bernhard Schulz, Alexandra A. Suvorova, Sarah E. M. Gain and Bogdan Z. Dlugogorski

Minerals engineering, Vol.204, 108398

2023

DOI: https://doi.org/10.1016/j.mineng.2023.108398

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Abstract

Carbonic acid process

Dissolution-precipitation mechanism

Lithium bicarbonate

Mass-transfer limitation

Pressure leach of spodumene

Weak acid process

This contribution develops a process for recovering lithium from β-spodumene by sequential pressure leach with solutions of carbonic acid, as a replacement for digestion of β-spodumene with concentrated sulfuric acid. Six sequential steps, each operated at 200 °C and 100 bar for 1 h, retrieve 75 % of lithium from the initial feed material. This compares with a 12.6 % Li recovery from a single-stage (batch) operation. We develop both the thermodynamic and mass-transfer models of the leach process and argue that the lithium extraction is mass-transfer controlled. The underlying mechanism involves: (i) near-instantaneous ion exchange between H+ for Li+ at the onset of the digestion; (ii) direct formation of amorphous Li-depleted rinds; (iii) precipitation of secondary minerals, boehmite (AlO(OH)) and skin-forming amorphous silica (SiO2), the latter only in the batch operation; (iv) counter-current diffusion of H+ and Li+ through the surface layer (surface layer = depleted sublayer + precipitation sublayer); (v) dissolution of the surface layer at the solid-solution interface, through the reactions with water. The evidence comes from the near-proportionality between the lithium recovery and mass of dissolved β-spodumene, no detection of keatite-HAlSi2O6, particle morphology, precipitation of amorphous skins of SiO2 decorated with boehmite specks observed by electron microscopy and predicted from thermodynamic modelling as well as from a mass-transfer analysis of the Li-recovery rates. Direct observations confirm the existence of a three-phase reacting system, as predicted from thermodynamic calculations, with the absence of a supercritical fluid phase. Lithium recoveries, of at least 28 % in a single step, are attainable, but only for long contact time of 48 h. Digestion lasting hundreds of hours is needed for the batch process to reach Li extraction corresponding to that of the sequential leach. The challenges for industrial implementation of the process comprise recycling of large amounts of water, avoiding the precipitation of silica that forms rinds, accelerating the hydrolysis of Li-depleted sublayer, concentrating the dilute solutions of Li+ and overcoming hesitance of industry to consider high-pressure treatment.

Details

Title: Pressure leach of β-spodumene with carbonic acid: Weak acid process for extraction of lithium
Authors/Creators: Mahmoud F. Alhadad - Murdoch University
Hans C. Oskierski - Murdoch University, Centre for Water, Energy and Waste
Johannes Chischi - Murdoch University
Gamini Senanayake - Murdoch University, Centre for Water, Energy and Waste
Bernhard Schulz - TU Bergakademie Freiberg
Alexandra A. Suvorova - Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, WA 6009, Australia
Sarah E. M. Gain - Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, WA 6009, Australia
Bogdan Z. Dlugogorski - Energy and Resources Institute, Charles Darwin University, Ellengowan Drive, Purple 12.01.08, Casuarina, NT 0810, Australia
Publication Details: Minerals engineering, Vol.204, 108398
Publisher: Elsevier Ltd
Identifiers: 991005606968307891
Murdoch Affiliation: Harry Butler Institute
Language: English
Resource Type: Journal article

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Collaboration types: Domestic collaboration; International collaboration
Citation topics: 2 Chemistry; 2.165 Nanofibers, Scaffolds & Fabrication; 2.165.1082 Calcium Carbonate Crystallization
Web Of Science research areas: Engineering, Chemical; Mineralogy; Mining & Mineral Processing
ESI research areas: Geosciences