Rare-Earth Separation Using PEI-CS2 Selective Precipitation
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Solution Overview
Problem
The challenge of separating rare-earth metals from other metals in admixture in aqueous solutions, particularly those in columns 4 to 14 of the Periodic Table, is a significant issue due to limited supply and growing demand, especially in industries like wind power and electric vehicles.
Innovation Solution
A process involving the addition of a polyethyleneimine-CS2 adduct in the form of a salt to the aqueous solution, followed by stirring, suspension formation, and liquid-solid separation, effectively isolating rare-earth elements by utilizing water-soluble polymers to enhance separation efficiency.
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 removes other metals (columns 4-14) from the aqueous solution containing rare-earth metals through selective precipitation. By targeting and removing the interfering metals first, the process simplifies the overall separation task while maintaining high purity for the rare-earth metals.
Solution Approach 2:
The patent uses an intermediary reagent (hydroxide or carbonate) to facilitate the selective separation process. This intermediary enables the precipitation of other metals at controlled pH levels, creating a simplified pathway to isolate rare-earth metals without requiring complex multi-step procedures.
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 invention employs inexpensive, readily available reagents (common hydroxides and carbonates) for the separation process. These low-cost chemicals can be used in a single step to achieve effective separation, eliminating the need for expensive specialized agents or multiple processing cycles.
Solution Approach 2:
The patent utilizes changes in pH parameters to achieve selective precipitation. By adjusting the pH to specific ranges, other metals are precipitated while rare-earth metals remain in solution, providing a cost-effective separation method based on simple parameter control rather than expensive materials.
3Ease of operation
If simple separation methods are used, then the process is easy to operate, but separation purity is insufficient
Solution Approach 1:
The invention segments the separation process into distinct stages: first precipitating other metals at controlled pH, then recovering rare-earth metals from the clarified solution. This segmentation maintains operational simplicity while achieving high purity through systematic, stepwise separation rather than attempting complex one-step purification.
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 a high purity separation of rare-earth metals, reducing the ratio of other metals in the solution and enabling efficient recovery, thus addressing the supply constraints and supporting the circular economy.
Implementation Method 1
stopping the stirring and waiting at least 5 minutes for a suspension S to form
Implementation Method 2
adding at least one polyethyleneimine-CS2 adduct in the form of a salt (PEI-CS2) to the aqueous solution AS
Implementation Method 3
performing a liquid/solid separation on the suspension S to obtain an aqueous solution L predominantly containing the elements among the rare-earth elements
Data Source
AI summary
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 and involves liquid/solid separation to obtain a solid predominantly containing the rare-earth elements.