Direct Lithium Extraction Circuit Using Monovalent Salt Impurity Displacement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional DLE processes face inefficiencies and high costs due to the carryover of impurities like boron, calcium, magnesium, potassium, manganese, and zinc, which complicate lithium recovery and require additional purification steps, and alumina-based adsorbents are ineffective in sulfate-containing solutions.
Innovation Solution
A process and circuit using continuous countercurrent adsorption and desorption with alumina-based lithium selective adsorbents, employing a monovalent salt solution for metathesis reactions to displace impurities, followed by a chloride wash to enhance lithium recovery and purity, with a recycle loop for displaced chloride salt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional precipitation softening is used to remove impurities, then impurity removal is achieved, but operational expenditure and waste treatment costs increase
Solution Approach 1:
The patent extracts and removes specific impurity ions (Ca2+, Mg2+, Mn2+, Zn2+) from the lithium eluate stream using selective precipitation and ion exchange processes, separating them from the lithium-containing stream to achieve high purity without requiring extensive chemical treatment of the entire feed stream
Solution Approach 2:
The patent introduces intermediate purification steps including selective precipitation reagents and ion exchange resins that act as mediators between the crude eluate and the final high-purity lithium product, enabling gradual purification with controlled chemical consumption
2Manufacturing precision
If ion exchange and solvent extraction are used to remove impurities, then impurity removal is achieved, but capital expenditure and maintenance costs increase
Solution Approach 1:
The patent segments the purification process into distinct functional units: a first ion exchange step for removing divalent cations, followed by a second ion exchange or solvent extraction step for further purification. This modular segmentation allows for targeted impurity removal while simplifying equipment design and reducing overall capital expenditure compared to single-stage complex systems
Solution Approach 2:
The patent applies different purification mechanisms (ion exchange vs. solvent extraction) to different stages of the purification process, with each stage optimized for specific impurity types. The first stage uses ion exchange for bulk removal of Ca2+, Mg2+, Mn2+, and Zn2+, while subsequent stages use alternative methods for trace impurity removal, creating locally optimized purification zones
3Manufacturing precision
If additional purification steps are added to achieve high purity, then lithium eluate purity is improved, but process efficiency decreases
Solution Approach 1:
The patent performs preliminary concentration of lithium from brine feedstock using evaporation or membrane processes before the purification stages, pre-concentrating the lithium to levels that reduce the volume requiring subsequent purification treatment. This preliminary action decreases the load on ion exchange and solvent extraction units, improving overall process efficiency while maintaining high purity output
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
Reduces capital and operational expenditures, improves lithium-to-impurity ratio, and enables high-purity lithium production suitable for battery applications by effectively removing impurities and optimizing resource use.
Implementation Method 1
alumina-based lithium selective adsorbents
Implementation Method 2
continuous countercurrent adsorption and desorption
Implementation Method 3
displaces the lithium-bearing solution with a monovalent salt solution to initiate a metathesis reaction
Implementation Method 4
deintercalates the formed LiCl with water or a dilute salt solution
Data Source
AI summary
A process and circuit for direct lithium extraction (DLE) from natural or synthetic lithium-bearing solutions is disclosed, utilizing an alumina-based lithium selective adsorbent. The process circuit employs a monovalent salt wash solution, such as sodium chloride (NaCl) or potassium chloride (KCl), to displace impurities (e.g., boron, calcium, magnesium) from the adsorbent, followed by elution with water or a dilute salt solution to recover lithium. The process circuit improves the lithium-to-impurity ratio in the eluate, reduces operational and capital expenditures, and minimizes waste by recycling displaced impurities into the brine feed stream.