Lithium Brine Purification via Membrane Concentration and Anion Conversion
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Solution Overview
Problem
Current methods for lithium extraction from brine sources are inefficient, requiring long processing times and achieving low yield, with a need for improved means to separate lithium from water in brine streams.
Innovation Solution
A method involving ion withdrawal, followed by membrane separation operations using semi-permeable membranes in series and counter-flow reverse osmosis to concentrate lithium, with recycling of dilute brine streams and permeate streams to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional evaporation pond methods are used to extract lithium from brine, then lithium can be recovered, but the process requires months to complete and achieves only 50-60% recovery yield
Solution Approach 1:
The patent extracts lithium from brine using selective adsorbents that selectively bind lithium ions, separating them from the bulk brine solution. This extraction mechanism enables faster recovery with higher yield by directly removing lithium rather than relying on slow evaporation processes.
Solution Approach 2:
The patent replaces the mechanical/physical evaporation process with a chemical adsorption process. Instead of using evaporation ponds where lithium crystallizes from evaporating water, the system uses adsorbent materials that chemically bind lithium ions, dramatically reducing processing time and improving recovery efficiency.
2Speed
If adsorbents are used to selectively recover lithium from brine, then lithium recovery speed increases, but the process requires handling large volumes of water
Solution Approach 1:
The selective adsorbent extracts lithium ions from the brine solution, concentrating the lithium in the adsorbent material while leaving the bulk water behind. This extraction approach enables fast lithium recovery by removing lithium directly from the solution phase without requiring processing of the entire water volume.
Solution Approach 2:
The patent changes the concentration parameter by using adsorbents with high lithium affinity, which concentrate lithium in a small volume of adsorbent material. This parameter change enables rapid lithium recovery while minimizing the volume of brine that needs to be processed, addressing the water volume issue.
3Manufacturing precision
If membrane separation operations are used to concentrate lithium extract, then lithium concentration increases to over 120,000 mg/l, but the device complexity increases
Solution Approach 1:
The patent segments the concentration process into multiple membrane separation stages, with each stage performing a specific separation function. This segmentation allows the system to achieve high lithium concentration (over 120,000 mg/l) by progressively concentrating the lithium extract through multiple controlled separation steps, managing complexity through modular stages.
Solution Approach 2:
The patent uses semi-permeable membranes as intermediary elements that facilitate selective separation. These membranes act as mediators between the lithium extract and the final concentrated product, enabling precise concentration control while managing system complexity through standardized membrane components.
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 method achieves high lithium concentration (up to 90% recovery) with a TDS over 120,000 mg/l, reducing fresh water demand and operational costs, and enables conversion to lithium carbonate or hydroxide.
Implementation Method 1
concentrating the lithium extract using a counter-flow reverse osmosis operation, to yield a lithium concentrate and a dilute brine stream
Implementation Method 2
extracting lithium from the brine source using an ion withdrawal process to form a lithium extract
Data Source
AI summary
Lithium recovery processes are described using concentration and conversion techniques. A vaporizer or membrane can be used to concentrate lithium and precipitate impurities. A conversion process can be used to replace anions in lithium bearing streams by adding a second anion and precipitating lithium in a salt with the second anion. Rotary separation can be used to separate the precipitated lithium salt.