Rare-Earth Separation Using Polyethyleneimine-CS2 Salt Precipitation
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Solution Overview
Problem
The challenge of separating rare-earth metals from other metals in admixture in aqueous solutions, particularly in the context of limited supply and growing demand, is a significant issue for promoting a circular economy and ensuring the availability of these critical metals.
Innovation Solution
A process involving the addition of a polyethyleneimine-CS2 adduct in the form of a salt to an aqueous solution, followed by stirring, suspension formation, and liquid-solid separation, effectively isolating rare-earth elements by utilizing the properties of polyethyleneimine-CS2 to neutralize cationic charges and facilitate separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods are used for rare-earth metals, then separation can be achieved, but the process becomes complex and costly
Solution Approach 1:
The invention extracts and utilizes the specific chemical property of rare-earth metals (cationic charge) to selectively bind them with polyethyleneimine-CS2 adduct. This extraction principle allows separation based on charge neutralization, simplifying the process from complex multi-step procedures to a single selective binding step followed by filtration.
Solution Approach 2:
The invention changes the chemical parameter of the separation system by introducing polyethyleneimine-CS2 adduct, which alters the charge state of rare-earth metal ions. This parameter change enables selective precipitation or phase separation, achieving high separation efficiency without complex equipment or multiple processing stages.
2Manufacturing precision
If conventional separation methods are used for rare-earth metals, then separation can be achieved, but the cost increases
Solution Approach 1:
The polyethyleneimine-CS2 adduct serves as a disposable reagent that can be added in controlled amounts, performs the separation function, and then is removed with the solid phase. This approach eliminates the need for expensive, reusable separation equipment and complex regeneration processes, significantly reducing overall process cost while maintaining high separation efficiency.
3Device complexity
If simple separation methods are used, then process complexity is reduced, but separation efficiency decreases
Solution Approach 1:
The polyethyleneimine-CS2 adduct acts as an intermediary substance that mediates between the rare-earth metal ions and the separation process. It selectively binds to rare-earth metals through charge neutralization, forming a distinct phase that can be easily separated by filtration or decantation, thus achieving high separation efficiency through a simple one-step 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
The process achieves a high recovery of rare-earth elements, with the separated solution predominantly containing these metals, while minimizing the presence of other metals, thus enhancing the efficiency and cost-effectiveness of rare-earth metal recovery.
Implementation Method 1
utilizing the properties of polyethyleneimine-CS2 to neutralize cationic charges and facilitate separation
Implementation Method 2
waiting at least 5 minutes for a suspension S to form
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a process for separating one or more elements among the rare-earth elements from other metals in columns 4 to 14 of the Periodic Table of the Elements, in admixture in aqueous solution. The process uses a polyethyleneimine-CS2 adduct in the form of a salt.