Membrane-Assisted Solvent Extraction for Rare Earth Recovery
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Solution Overview
Problem
Current methods for recovering rare earth elements from post-consumer products are inefficient, leading to low recycling rates due to high chemical usage, co-extraction of non-rare earth elements, slag formation, and high environmental impact, with existing solvent extraction processes limited by equilibrium-based separation and requiring multiple steps.
Innovation Solution
Membrane-assisted solvent extraction using permeable hollow fibers with an immobilized organic phase, allowing simultaneous extraction and stripping of rare earth elements in a continuous process, overcoming equilibrium limitations and achieving high purity without the need for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional solvent extraction is used, then rare earth elements can be recovered, but the process is limited by equilibrium-based separation requiring multiple steps and separate extraction and stripping operations
Solution Approach 1:
The patent combines extraction and stripping operations into a single integrated membrane module. The organic phase is immobilized within the membrane structure, allowing feed solution to contact the membrane for extraction while strip solution simultaneously contacts the opposite side for stripping, eliminating the need for separate operational steps and equipment
Solution Approach 2:
The membrane with immobilized organic phase acts as an intermediary between the feed solution and strip solution. This mediator enables mass transfer of rare earth elements from the feed side to the strip side while maintaining phase separation, overcoming the equilibrium limitations of conventional extraction by providing a continuous transport pathway
2Quantity of substance
If hydrometallurgical processes are used, then rare earth elements can be dissolved and precipitated, but high chemical usage and co-extraction of non-rare earth elements occur
Solution Approach 1:
The patent employs selective extractants immobilized in the membrane that exhibit specific affinity for rare earth elements. This local chemical functionality within the membrane structure enables selective extraction of rare earth elements from the feed solution while leaving non-rare earth elements behind, achieving high separation precision without excessive chemical consumption
3Loss of substance
If pyrometallurgical processes are used, then rare earth elements can be recovered by re-melting, but slag formation occurs and loss of rare earth elements due to carbon and oxygen contents
Solution Approach 1:
The patent replaces the high-temperature pyrometallurgical mechanical system with a low-temperature membrane-based mass transfer system. This substitution eliminates the need for high-temperature furnaces that cause slag formation and rare earth element loss through reactions with carbon and oxygen, achieving recovery without these harmful effects
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 enables the selective recovery of rare earth elements in a highly pure form, reducing environmental impact and operational costs, while minimizing extractant loss and co-extraction of non-rare earth elements, thus improving the efficiency and sustainability of the recovery process.
Implementation Method 1
membrane assisted solvent extraction using an immobilized organic phase within the pores of permeable hollow fibers
Implementation Method 2
The permeable hollow fibers are contacted by an aqueous feed solution on one side thereof, and a strip solution on another side thereof, to provide the simultaneous extraction and stripping of rare earth elements
Data Source
AI summary
Systems and methods for the recovery of rare earth elements are provided. The systems and methods generally include membrane assisted solvent extraction using permeable hollow fibers having an immobilized organic phase within the pores of the hollow fibers. The permeable hollow fibers are generally in contact with an acidic aqueous feed on one side thereof and a strip solution on another side thereof. The systems and methods generally include the simultaneous extraction and stripping of rare earth elements as a continuous recovery process that is well suited for post-consumer products, end-of-life products, and other recovery sources of rare earth elements.