Lithium Adsorbent Composition for Low-Loss Salt Lake Extraction
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Solution Overview
Problem
Current lithium adsorbents used in salt lake brines with high magnesium-to-lithium ratios suffer from low adsorption efficiency, high self-dissolution loss rates, and require significant water and energy consumption during the extraction process.
Innovation Solution
A lithium adsorbent composed of a vinylidene fluoride-chlorotrifluoroethylene (VDF-CTFE) copolymer or fluoroolefin-vinyl ether copolymer binder, combined with a wetting and dispersing agent like polyethylene glycol, enhances mechanical strength and reduces dissolution loss, improving adsorption efficiency and reducing water consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional lithium adsorbents are used for lithium extraction from salt lake brines, then the adsorption method can be applied, but the adsorption efficiency to lithium is low and the self-dissolution loss rate is high
Solution Approach 1:
The patent uses a composite binder system comprising fluorocarbon resin and polyacrylonitrile in a specific weight ratio (9:1 to 1:9). This composite material combines the advantages of both components: fluorocarbon resin provides chemical stability and low dissolution loss, while polyacrylonitrile enhances lithium adsorption capacity. The synergistic effect resolves the contradiction between adsorption efficiency and dissolution loss by creating a binder that simultaneously achieves both properties.
Solution Approach 2:
The patent optimizes the molecular weight of the fluorocarbon resin to be 100,000-800,000 and the weight ratio of fluorocarbon resin to polyacrylonitrile to be 9:1 to 1:9. These parameter changes are critical: the high molecular weight reduces dissolution loss while maintaining mechanical strength, and the optimized weight ratio balances adsorption efficiency with chemical stability. By precisely controlling these parameters, the patent resolves the contradiction between high adsorption efficiency and low dissolution loss.
2Strength
If the adsorbent structure is made stronger to reduce dissolution loss, then the mechanical strength increases, but the lithium adsorption efficiency decreases
Solution Approach 1:
The composite binder of fluorocarbon resin and polyacrylonitrile creates a synergistic structure where fluorocarbon resin forms a strong, stable matrix that provides mechanical strength and structural integrity, while polyacrylonitrile introduces polar groups that enhance lithium adsorption. This composite approach resolves the contradiction by allowing the strong fluorocarbon backbone to provide mechanical strength while the polyacrylonitrile component maintains high adsorption efficiency.
Solution Approach 2:
The binder composition is designed with local quality differentiation: the fluorocarbon resin provides the structural framework with high mechanical strength and low dissolution, while the polyacrylonitrile components are distributed within this framework to provide localized lithium adsorption sites. This spatial distribution of different functional properties within the binder resolves the contradiction between overall mechanical strength and localized adsorption efficiency.
3Ease of operation
If more water is used for washing and desorption, then the lithium can be more effectively removed from the adsorbent, but the water consumption increases and lithium loss during cleaning increases
Solution Approach 1:
The fluorocarbon resin component is specifically selected to extract and provide water-repellent properties to the adsorbent structure. By incorporating this hydrophobic material into the binder, the adsorbent surface becomes less wettable, reducing the amount of water that penetrates and adheres to the adsorbent during washing and desorption processes. This resolves the contradiction by enabling effective lithium removal while minimizing water consumption and associated lithium loss.
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 adsorbent achieves increased lithium adsorption efficiency, lower water consumption, and reduced energy use, resulting in a high-yield, cost-effective lithium extraction process suitable for industrial-scale operations.
Implementation Method 1
The binder includes at least one of a vinylidene fluoride-chlorotrifluoroethylene (VDF-CTFE for short) copolymer and a fluoroolefin-vinyl ether copolymer
Implementation Method 2
The wetting and dispersing agent includes one or more of polyethylene glycol, sodium polyacrylate, polyvinyl alcohol, and formaldehyde condensate
Implementation Method 3
The wetting and dispersing agent includes one or more of polyethylene glycol, sodium polyacrylate, polyvinyl alcohol, and formaldehyde condensate
Implementation Method 4
A salt lake brine is contacted with the lithium adsorbent according to the first aspect of the present disclosure to carry out lithium adsorption
Implementation Method 5
the lithium adsorbent used is low in adsorption efficiency to lithium
Implementation Method 6
The lithium-rich adsorbent is washed, and lithium desorption is carried out with a desorbent, to obtain a desorption solution
Data Source
AI summary
A lithium adsorbent includes an aluminum-based adsorbing material, a binder, and a wetting and dispersing agent. The binder includes at least one of a vinylidene fluoride-chlorotrifluoroethylene (VDF-CTFE) copolymer and a fluoroolefin-vinyl ether copolymer. The wetting and dispersing agent includes one or more of polyethylene glycol, sodium polyacrylate, polyvinyl alcohol, and formaldehyde condensate.