Lithium Extraction from Brine via Continuous Ion Exchange
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Solution Overview
Problem
The adsorption method for extracting lithium from brine suffers from high impurity concentrations in the desorption section, leading to reduced application efficiency due to the low lithium adsorption capacity of aluminum-based adsorbents, which requires frequent switching between brine and water, introducing impurities into the qualified solution.
Innovation Solution
A continuous ion exchange process is implemented, including an adsorption section using an aluminum-based lithium adsorbent, a water-pushing-material section, a desorption section where the adsorbent is desorbed with pure water and the desorption solution is collected in segments, and a material-pushing-water section, optimizing the adsorption and desorption flows by using a front-segment collected liquid with specific conductivity and impurity concentration parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequent switching between brine and water is performed in adsorption and desorption cycle, then lithium adsorption capacity is improved, but impurity concentration in qualified solution increases
Solution Approach 1:
The patent segments the desorption process into multiple stages: initial desorption stage, middle desorption stage, and final desorption stage. By collecting desorption solution in segments and selectively discarding or utilizing different segments, the system separates high-purity lithium solution from impurity-containing solutions, thereby improving qualified solution quality while maintaining adsorption productivity
Solution Approach 2:
The patent extracts and removes the harmful initial desorption liquid containing high concentrations of impurities (sodium, potassium, calcium, magnesium) from the system. This extracted impurity-rich liquid is discarded or used for regenerating other adsorbent columns, preventing these impurities from contaminating the qualified lithium solution
2Adaptability or versatility
If aluminum-based adsorbent is used, then selectivity is improved, but lithium adsorption capacity decreases
Solution Approach 1:
The patent implements a continuous multi-column adsorption-desorption system where multiple adsorbent columns operate in sequence. While one column is in desorption mode, others are in adsorption mode, ensuring continuous lithium extraction. This continuity compensates for the lower capacity of aluminum-based adsorbents by increasing the overall throughput and utilization efficiency
Solution Approach 2:
The patent discards the initial desorption liquid containing impurities and recovers the middle and final desorption liquids containing concentrated lithium. This selective recovery approach maximizes the utilization of lithium from aluminum-based adsorbent while discarding impurity-laden solutions, effectively addressing both selectivity and capacity concerns
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 enhances the quality of the desorption solution, improves the use efficiency of the adsorbent per unit time, reduces desorption water consumption, and increases the quality of the qualified solution by effectively managing impurities and optimizing the ion exchange process.
Implementation Method 1
performing extraction on the brine through a continuous ion exchange process, where the continuous ion exchange process includes an adsorption section, a water-pushing-material section, a desorption section, and a material-pushing-water section; in the adsorption section, adsorption is performed on the brine with an aluminum-based lithium adsorbent
Implementation Method 2
in the desorption section, the aluminum-based lithium adsorbent is desorbed with pure water, and a desorption solution is collected in segments
Data Source
Figure 1
AI summary
Disclosed are a method for extracting lithium from brine, and an application. The method includes performing extraction on the brine through a continuous ion exchange process, where according to the continuous ion exchange process, in an adsorption section, adsorption is performed on the brine with an aluminum-based lithium adsorbent; in a water-pushing-material section, a resin column is washed with a solution; in a desorption section, desorption is performed with pure water, and a desorption solution is collected in segments; and in a material-pushing-water section, a solution in a resin column is replaced by spent brine. The solution used in the water-pushing-material section is a front-segment collected liquid in the desorption section, and the front-segment collected liquid satisfies the following parameter: 520 us*cm−1<B<1860 us*cm-1, where B=conductivity*lithium concentration/total impurity concentration), a unit of the conductivity is us*cm-1, a unit of the lithium concentration and a unit of the total impurity concentration are both mg/L, and the total impurity includes potassium, sodium, calcium, magnesium, and boron. Desorption assistance is realized after a water-pushing-material operation is performed with the front-segment collected liquid collected in segments in the desorption section. Therefore, efficiency of the adsorbent is improved, desorption water consumption is reduced, and a quality of a qualified solution is enhanced.