Membrane Solvent Extraction for Lithium Aluminum Separation
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Solution Overview
Problem
Current methods for lithium recovery from geothermal brines and clay minerals are energy-intensive, costly, and inefficient, producing high amounts of waste and requiring multiple steps, making them unsuitable for large-scale, cost-effective industrial applications.
Innovation Solution
A membrane solvent extraction method using hydrophobic hollow fibers with a cationic extractant like di-(2-ethylhexyl)phosphoric acid (DEHPA) immobilized in the porous sidewalls, which selectively extracts aluminum while rejecting lithium, allowing for continuous recirculation of feed and strip solutions to achieve high-purity lithium recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mining methods are used to recover lithium, then lithium production capacity increases, but energy consumption and costs increase significantly
Solution Approach 1:
The patent changes the chemical parameters of the extraction process by using a cationic extractant with specific chemical properties that selectively interact with lithium ions. The extractant is designed with a specific charge and molecular structure that enables selective lithium extraction from brine, improving productivity while reducing energy consumption compared to conventional methods
Solution Approach 2:
The cationic extractant acts as an intermediary substance between the lithium-containing brine and the purification process. This intermediary selectively binds with lithium ions, enabling efficient separation and recovery with lower energy requirements than direct conventional extraction methods
2Productivity
If sorption-based systems are used for lithium recovery from geothermal brines, then lithium can be recovered, but the process is inefficient in terms of time, energy, and cost
Solution Approach 1:
The patent replaces the mechanical sorption-based system with a chemical extraction system using cationic extractants. This substitution enables faster and more efficient lithium recovery by utilizing chemical selectivity rather than physical sorption, significantly reducing process time and energy requirements while maintaining high recovery efficiency
3Manufacturing precision
If solvent extraction methods are used to separate lithium from other metals, then lithium separation is achieved, but the process is costly and generates large amounts of waste
Solution Approach 1:
The cationic extractant is designed with specific local chemical properties that create selective interaction with lithium ions while being inert toward other metals. This local quality specificity enables high lithium purity separation without requiring extensive waste treatment processes, reducing both manufacturing precision requirements and waste generation
Solution Approach 2:
The patent converts the potential harm of processing complex brine compositions into a benefit by using the cationic extractant's selective affinity for lithium. This selective interaction naturally separates lithium from other metals and impurities, turning a complex separation problem into an efficient selective extraction process that minimizes waste
4Manufacturing precision
If multiple steps are used in lithium recovery processes, then purification can be achieved, but the process complexity and costs increase
Solution Approach 1:
The patent merges multiple separation functions into a single extraction step using the cationic extractant. This unified approach simultaneously achieves lithium recovery, purification, and concentration in one process operation, eliminating the need for multiple separate steps and significantly reducing process complexity while maintaining high purity
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
This method significantly reduces energy consumption and costs, achieving lithium recovery with >94% purity, optionally >99%, while minimizing waste production and simplifying the process into fewer steps, making it more environmentally friendly and efficient.
Implementation Method 1
The plurality of hollow fibers are hydrophobic and include a porous sidewall defining a lumen side spaced apart from a shell side. The method further includes wetting the porous sidewall of the plurality of hollow fibers with an organic phase. The organic phase includes a cationic extractant and an organic solvent, and the organic phase is immobilized in the porous sidewall.
Data Source
AI summary
A method of separating lithium (Li) from aluminum (Al) includes: obtaining an aqueous feed solution containing an acid, Li, and Al; providing a membrane module including a plurality of hollow fibers that are hydrophobic and include a porous sidewall defining a lumen side spaced apart from a shell side; wetting the porous sidewall of the plurality of hollow fibers with an organic phase including a cationic extractant and an organic solvent such that the organic phase is immobilized in the porous sidewall; performing membrane solvent extraction by passing the feed solution along one of the lumen side or the shell side of the plurality of hollow fibers and simultaneously passing a strip solution along the other of the lumen side or the shell side of the plurality of hollow fibers. The cationic extractant in the porous sidewall continuously extracts Al from the feed solution while substantially rejecting Li for recovery.