Selective Lithium Brine Adsorption in a Countercurrent Recovery Circuit
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Solution Overview
Problem
Conventional methods for lithium recovery from brines are inefficient, requiring large amounts of water and chemicals, and are economically non-viable, especially in regions with limited fresh water resources.
Innovation Solution
A continuous countercurrent adsorption and desorption (CCAD) process using lithium selective adsorbents, such as lithium alumina intercalates and layered double hydroxides, to selectively recover lithium from brines, with a circuit configuration including brine displacement, loading, entrainment rejection, and elution zones, enhancing lithium concentration and recovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional evaporation ponds and fixed-bed systems are used for lithium recovery, then lithium can be extracted from brines, but the process requires excessive water and reagents, making it economically non-viable
Solution Approach 1:
The patent implements a continuous countercurrent adsorption-desorption process where multiple adsorbent beds operate in sequence, with beds continuously cycling between adsorption and regeneration phases. This continuous operation eliminates the batch processing inefficiencies of fixed-bed systems and maintains constant lithium concentration in the product stream, achieving high productivity with reduced water consumption.
Solution Approach 2:
The process employs periodic switching between adsorption and desorption modes for each adsorbent bed through a multi-position valve system. Beds are cyclically moved between service, regeneration, and rinse positions, allowing simultaneous lithium capture and adsorbent regeneration. This periodic action enables continuous production while minimizing water and reagent requirements compared to conventional methods.
2Manufacturing precision
If fixed-bed systems are used for lithium adsorption, then lithium can be concentrated, but the performance is weaker and water requirements are higher compared to continuous countercurrent systems
Solution Approach 1:
The system divides the lithium concentration process into multiple discrete adsorbent beds (typically 3-5 beds) that operate in sequence. Each bed performs a specific function (adsorption, rinsing, regeneration) and the combined output achieves high lithium concentration purity. This segmentation allows optimization of each stage while reducing overall water and reagent requirements compared to a single fixed-bed system.
Solution Approach 2:
The patent introduces an intermediary rinse solution that recycles water through the system. The rinse solution, which contains some lithium, is directed to the regeneration stage rather than being discarded, and fresh water is added to maintain the cycle. This intermediary approach minimizes water loss while maintaining high product purity through controlled rinsing of the adsorbent beds.
3Adaptability or versatility
If conventional processing techniques are used in regions with declining fresh water availability, then lithium extraction can proceed, but the economic advantage disappears due to high water consumption
Solution Approach 1:
The process fundamentally changes the water consumption parameter by implementing a closed-loop continuous system where water is recycled through multiple stages. The countercurrent design ensures that water is used most efficiently, with the least contaminated water contacting the most highly concentrated lithium stream. This parameter change reduces water consumption by an order of magnitude compared to conventional evaporation ponds, making the process economically viable in water-scarce regions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The CCAD process achieves high lithium recovery rates (up to 97%) with reduced water and reagent usage, producing high-purity lithium products suitable for battery-grade materials, and is more efficient than fixed-bed systems.
Implementation Method 1
contacting the brine solution with a lithium selective adsorbent using a continuous countercurrent adsorption and desorption (CCAD) process
Implementation Method 2
The loaded adsorbent is eluted with a solution to produce a concentrated lithium product stream
Data Source
AI summary
This invention relates generally to a process for selective adsorption and recovery of lithium from natural and synthetic brines, and more particular to a process for recovering lithium from a natural or synthetic brine solution by passing the brine solution through a lithium selective adsorbent in a continuous countercurrent adsorption and desorption circuit.