Lithium Recovery Adsorbent Eluent Selection
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Solution Overview
Problem
Current methods for recycling lithium from lithium-ion batteries, such as hydrometallurgy and pyrometallurgy, face inefficiencies in separating lithium from acidic brine solutions, leading to high costs and material losses, especially when using hydrochloric acid for desorption, which dissolves the adsorbent and results in lower lithium concentration for battery-grade production.
Innovation Solution
A method involving the use of an adsorption process with an adsorbent column, where brine is treated with a mixture of water and acetic acid, sodium peroxodisulfate, or ammonium peroxodisulfate as eluents, which reduces adsorbent dissolution and allows for effective lithium ion desorption, enabling higher lithium concentration and purity with lower economic and handling risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrochloric acid is used for desorption, then lithium ions are effectively desorbed from the adsorbent, but the adsorbent dissolves significantly leading to material loss and higher costs
Solution Approach 1:
The patent changes the chemical parameters of the eluent by replacing hydrochloric acid with alternative acids (sulfuric acid, nitric acid, acetic acid) or their mixtures with salts. This parameter change reduces the adsorbent dissolution while maintaining effective lithium desorption, resolving the contradiction between desorption efficiency and material loss.
Solution Approach 2:
The patent introduces salt additives (such as sodium chloride, potassium chloride, ammonium chloride) as intermediary substances in the eluent. These salts act as mediators that enhance lithium desorption from the adsorbent while reducing the direct corrosive interaction between the acid and the adsorbent, thereby reducing material loss.
2Quantity of substance
If conventional separation methods are used to concentrate lithium from brine, then lithium can be recovered, but the process becomes costly and complex
Solution Approach 1:
The patent extracts lithium ions from complex brine matrices using selective adsorbents (manganese oxide, lithium aluminum layer double hydroxide, lithium titanium oxide). This extraction approach isolates lithium from other ions in a single step, simplifying the separation process while achieving high concentration factors.
Solution Approach 2:
The patent employs porous adsorbent materials with specific structures (layered double hydroxides, oxide surfaces) that provide high surface area and selective binding sites for lithium ions. These porous materials enable efficient lithium uptake from dilute brine, achieving high concentration without complex multi-stage separation equipment.
3Reliability
If hydrochloric acid is used for desorption, then lithium recovery is achieved, but handling risks and operational costs increase
Solution Approach 1:
The patent replaces expensive and hazardous hydrochloric acid with cheaper, safer alternative acids (acetic acid, sulfuric acid) and their salt mixtures. These alternatives provide sufficient lithium desorption capability while being easier and safer to handle, reducing operational risks and costs.
Solution Approach 2:
The patent converts the potential harm of acid corrosion into a beneficial selectivity mechanism. By using alternative acids and salt mixtures, the process achieves effective lithium desorption while minimizing unwanted side reactions and adsorbent degradation, turning a harmful chemical environment into a controlled and selective separation process.
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 achieves efficient lithium recovery with minimal adsorbent loss, allowing for the production of battery-grade lithium, supporting a circular economy by maintaining lithium quality and reducing operational costs, with the added benefit of using inexpensive and safer eluents compared to hydrochloric acid.
Implementation Method 1
introducing brine into an adsorber column which is at least partially filled with an adsorbent, so that lithium ions are absorbed on the adsorbent
Implementation Method 2
introducing an eluent (solvent used for elution) into the adsorber column so that the lithium ions absorbed on the absorbent are desorbed
Data Source
Figure 1
Figure 2
AI summary
An adsorption process for obtaining lithium from a brine is proposed, in which desorption is carried out using an eluent, wherein the eluent is a mixture of water and acetic acid and/or water and sodium peroxodisulfate and/or water and ammonium peroxodisulfate.