Ionic Liquid Countercurrent Extraction for Rare Earth Separation
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Solution Overview
Problem
Current methods for extracting and separating rare earth metals from each other are inefficient, requiring multiple stages, using toxic solvents, and are not environmentally friendly, with existing extractants showing low selectivity and stability issues.
Innovation Solution
The use of a specifically designed ionic liquid with a cationic species having a central nitrogen donor atom and electron donating groups, which selectively extracts rare earth metals through countercurrent extraction, reducing the number of separation stages needed and improving extractability and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organophosphorus extractants are used for liquid-liquid extraction, then the process is scalable and adaptable, but the separation factor is low requiring multiple stages and additional processing steps
Solution Approach 1:
The patent changes the chemical parameters of the extractant by using ionic liquids with specific cationic structures (containing central nitrogen donor atoms and electron donating groups) instead of conventional organophosphorus extractants. This parameter change results in significantly higher separation factors (over 1000:1 for dysprosium and neodymium) and allows for single-contact separation, eliminating the need for multiple processing stages while maintaining scalability.
Solution Approach 2:
The invention employs composite ionic liquid extractants that combine specific cationic species with central nitrogen donor atoms and electron donating groups. This composite material design achieves both high separation efficiency and extractability, resolving the contradiction between separation efficiency and processing complexity by enabling single-stage separation with a single contact.
2Productivity
If conventional extractants are used, then the process can be implemented commercially, but toxic organic solvents are required which are not environmentally friendly
Solution Approach 1:
The patent changes the physical and chemical parameters of the extractant medium by replacing conventional toxic organic solvents with ionic liquids. Ionic liquids have negligible vapor pressure, are non-flammable, and exhibit low toxicity, thereby eliminating environmental hazards while maintaining commercial viability through scalable liquid-liquid extraction processes.
Solution Approach 2:
The invention converts the traditionally harmful organic solvents into beneficial ionic liquids that retain the advantages of liquid-liquid extraction (scalability, adaptability, recyclability) while eliminating toxicity, volatility, and flammability. This transformation allows the process to be both commercially viable and environmentally friendly.
3Quantity of substance
If existing extractants are used, then separation can be achieved, but selectivity for individual rare earth metals is low
Solution Approach 1:
The patent applies local quality by designing ionic liquid extractants with specific local structural features - central nitrogen donor atoms surrounded by electron donating groups. This localized structural design creates highly selective coordination environments that differentiate between individual rare earth metals based on their ionic radii and electronic properties, achieving separation factors of over 1000:1 for dysprosium and neodymium.
Solution Approach 2:
The invention changes the chemical parameters of the extractant to include ionic liquids with specific cationic structures containing central nitrogen donor atoms and electron donating groups. This parameter change dramatically improves selectivity for individual rare earth metals while maintaining adequate extractability, resolving the contradiction between quantity of substance separated and manufacturing precision of separation.
4Manufacturing precision
If multiple extraction stages are used to improve separation, then purity increases, but processing time and cost increase
Solution Approach 1:
The patent changes the extractant parameters to use ionic liquids with central nitrogen donor atoms and electron donating groups, which achieve separation factors of over 1000:1 in a single contact. This single-contact separation achieves high purity (greater than 99.9% for dysprosium and neodymium) without requiring multiple extraction stages, thereby eliminating the trade-off between purity and processing time.
Solution Approach 2:
The invention performs preliminary action by designing ionic liquid extractants with optimized structures that achieve complete separation in a single contact. This preliminary optimization of the extractant structure eliminates the need for subsequent purification stages, reducing processing time while maintaining high purity products.
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 high selectivity and extractability, allowing for the separation of rare earth metals like dysprosium and neodymium with a separation factor of over 1000:1 in a single contact, reducing processing costs and environmental impact.
Implementation Method 1
countercurrently contacting an acidic solution of the rare earth metal with a composition which comprises an ionic liquid to form an aqueous phase and a non-aqueous phase into which the rare earth metal has been selectively extracted
Data Source
AI summary
A method for extracting a rare earth metal from a mixture of one or more rare earth metals, said method comprising countercurrently contacting an acidic solution of the rare earth metal with a composition which comprises an ionic liquid to form an aqueous phase and a non-aqueous phase into which the rare earth metal has been selectively extracted.