Crystallization of NaHCO3 for concomitant CO2 sequestration and enrichment of lithium cations concentration in high salinity brines
Continental brines, with total dissolved solids ranging from 170–350 g l ^−1 , are the most abundant lithium resources, although lithium is one of the minor brine components, at concentrations around 1%. Amongst several requirements, for an efficient lithium recovery, it is imperative to improve the...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
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| Series: | Sustainability Science and Technology |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/2977-3504/adc45e |
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| Summary: | Continental brines, with total dissolved solids ranging from 170–350 g l ^−1 , are the most abundant lithium resources, although lithium is one of the minor brine components, at concentrations around 1%. Amongst several requirements, for an efficient lithium recovery, it is imperative to improve the Li ^+ to Na ^+ concentration ratio. Here we report a membrane electrolysis process for Na ^+ abatement from brines avoiding solid incrustations inside the reactor and minimizing lithium losses. Sodium is precipitated by CO _2 absorption and conversion to bicarbonate anions under basic conditions. Variables such as CO _2 flow rate and applied current densities were modified under different experimental designs. Three different arrangements were tested, with the best results found for an uncoupled CO _2 conversion and the recovery of the effluent from solid washing. Following this strategy, a reduction in the Na ^+ content of approximately 70% was achieved with a decrease of more than 3-fold in the Na ^+ /Li ^+ ratio of concentrations. Lithium recoveries of up to 66.6% in the catholyte were obtained with a mass balance close to 100% for both lithium and sodium. The proposed methodology has the potential to capture about 146.4 g of CO _2 per liter of electrolyzed brine, permanently storing CO _2 as mineral carbonates. |
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| ISSN: | 2977-3504 |