Lithium Recovery from Waste Li-Ion Batteries via Salt Separation
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Solution Overview
Problem
Conventional wet processes for recovering lithium from waste lithium-ion batteries result in low recovery rates and inefficient recycling of mineral acids and alkali sources, leading to increased concentrations of non-lithium cations and waste generation.
Innovation Solution
A method involving the use of sodium hydroxide or potassium hydroxide in the dissolution and neutralization steps, followed by solvent extraction and membrane electrolysis to separate and recover lithium, with the potential reuse of mineral acids and alkalis in the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wet process is used to separate and refine lithium from waste lithium-ion batteries, then the process can recover valuable metals, but the recovery rate of lithium is significantly decreased due to increased concentration of non-lithium cations
Solution Approach 1:
The patent extracts and removes non-lithium cations (sodium, potassium, magnesium, calcium) from the aqueous solution containing lithium salts through selective precipitation and solvent extraction processes. This separation removes the harmful impurities that would otherwise compete with lithium during recovery, thereby improving lithium recovery rate while reducing the concentration of non-lithium cations in the final product
Solution Approach 2:
The patent changes chemical parameters such as pH levels, temperature, and reagent concentrations to optimize the separation process. By adjusting these parameters, the process selectively precipitates or extracts non-lithium cations while keeping lithium in solution, thus improving lithium recovery rate and reducing impurity concentration
2Productivity
If conventional wet process is used with mineral acid and alkali compound, then the valuable metals can be dissolved and separated, but the mineral acid and alkali compound are drained as salts with no recycling technique
Solution Approach 1:
The patent recovers and reuses the mineral acid and alkali compound that would otherwise be lost as waste salts. Through membrane electrolysis and other separation techniques, the process regenerates the acid and base reagents from the salt byproducts, allowing them to be recycled back into the dissolution and neutralization steps, thereby eliminating waste and reducing operational costs
Solution Approach 2:
The system performs self-service by using the salt byproducts generated in the process to regenerate the necessary acid and base reagents through membrane electrolysis. This internal recycling mechanism allows the process to sustain itself without external input of fresh chemicals, improving both productivity and reducing substance loss
3Ease of manufacture
If compound other than lithium compound is used as alkali source in dissolution step, then the dissolution process can proceed, but the concentration of lithium ions decreases while concentration of other cations increases
Solution Approach 1:
The patent removes non-lithium cations introduced during dissolution with alternative alkali sources through selective separation processes. By extracting and removing these competing cations (sodium, potassium, magnesium, calcium) from the solution, the process maintains high lithium ion concentration despite using cost-effective alternative alkali sources, thus preserving measurement precision while maintaining ease of manufacture
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 recovery rates while allowing the recycling of salts produced in the process, reducing waste and operational costs through closed-loop recycling.
Implementation Method 1
a first lithium salt aqueous solution and an aqueous solution of a salt of at least one selected from the group consisting of sodium and potassium are membrane-electrolyzed using an ion exchange membrane
Implementation Method 2
the mineral acid obtained by membrane-electrolyzing a preferably separated aqueous solution of a salt of at least one selected from the group consisting of sodium and potassium
Data Source
AI summary
A method for recovering lithium from waste lithium-ion batteries, the method including: a dissolution step of dissolving active material powder obtained by pre-processing waste lithium-ion batteries in a mineral acid; a neutralization step of adding at least one selected from the group consisting of sodium hydroxide and potassium hydroxide to a solution obtained in the dissolution step; a solvent extraction step of separating at least one metal excluding lithium from a solution obtained in the neutralization step by organic solvent extraction to obtain an alkali mixed salt aqueous solution; a separation step of separating each of a lithium salt and a salt of at least one selected from the group consisting of sodium and potassium from the alkali mixed salt aqueous solution; and a lithium recovery step of recovering lithium from a first lithium salt aqueous solution obtained in the separation step.