Ionic Liquid Extraction of Rare Earth Metals
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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 struggling with selectivity and extractability, leading to high costs and environmental concerns.
Innovation Solution
The use of a specific ionic liquid with a cation comprising certain nitrogen-containing groups and a phosphinate anion for selective extraction and separation of rare earth metals from acidic solutions, forming a non-aqueous phase for enhanced selectivity and extractability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If commercial organophosphorus extractants are used for liquid-liquid extraction, then the process is scalable and recyclable, but the separation factor between rare earth metals is low requiring many stages
Solution Approach 1:
The patent modifies the chemical structure of extractants by introducing specific functional groups (such as polyoxin groups, hydrazine groups, or hydroxamic acid groups) to change the chemical parameters of the extractant. This structural modification enables the extractant to achieve high separation factors (exceeding 1000:1) while maintaining the scalability and recyclability of the liquid-liquid extraction process
Solution Approach 2:
The patent employs composite extractant systems that combine multiple functional groups or hybridize different extractant molecules to achieve both high selectivity and extractability. These composite extractants integrate the advantages of different chemical groups to simultaneously provide high separation factors and maintain process scalability
2Manufacturing precision
If multiple separation stages are used to achieve high purity rare earth metals, then separation efficiency improves, but processing costs increase manifold
Solution Approach 1:
By changing the chemical parameters of the extractant through structural modification (adding specific functional groups), the patent achieves ultra-high separation factors that enable single-stage or two-stage extraction to reach industrial purity levels, eliminating the need for multiple sequential separation stages and their associated costs
3Productivity
If conventional extractants are used, then extraction can be performed, but toxic organic solvents are required which are not environmentally friendly
Solution Approach 1:
The patent develops water-miscible extractants that can be easily degraded or disposed of without environmental harm, replacing persistent toxic organic solvents. These extractants maintain high extraction capability while being environmentally benign, allowing for sustainable rare earth metal separation
Solution Approach 2:
The patent changes the physical and chemical parameters of the extractant by introducing water-miscible functional groups, enabling the extractant to work in aqueous environments without requiring toxic organic solvents. This parameter change maintains extraction efficiency while eliminating environmental hazards
4Quantity of substance
If high concentrations of extractant are used to improve extractability, then rare earth metal extraction increases, but the complexity of extractant synthesis and stability decreases
Solution Approach 1:
The patent optimizes the concentration and molecular structure of the extractant to achieve high extractability at lower concentrations. By modifying the chemical structure (adding specific functional groups), the extractant's affinity for rare earth metals is enhanced, allowing effective extraction without requiring high concentrations that would complicate synthesis and reduce stability
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, reducing the number of separation stages needed while minimizing environmental impact by using a safer, more environmentally friendly solvent system, as demonstrated by separation factors exceeding 1000:1 for certain rare earth metal pairs.
Implementation Method 1
liquid-liquid extraction has been found to be the most suitable commercial process owing to its scalability, adaptability, and recyclability
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 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, wherein the ionic liquid has the formula [Ca++][X′], where [X′] represents a phosphinate anion.