Microwave-Assisted REE Extraction from Hyperaccumulators
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Solution Overview
Problem
Existing REE extraction technologies from REE hyperaccumulators suffer from poor efficiency, leading to limited application in tailings remediation and phytomining, with methods like centralized landfill and incineration causing seepage and heavy metal pollution, necessitating an effective treatment and resource utilization strategy.
Innovation Solution
A method involving microwave-assisted digestion of REE hyperaccumulators followed by absorption using a chelating resin, and subsequent precipitation and calcination to obtain high-purity rare earth oxides, which includes washing, drying, and crushing the hyperaccumulators, adding a digestion solution for microwave digestion, adjusting pH, filtering, adsorbing on a chelating resin, eluting with nitric acid, forming a rare earth oxalate precipitate, and calcining to produce high-purity rare earth oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional extraction methods (centralized landfill, incineration, composting) are used to treat REE hyperaccumulators, then the treatment process can be implemented, but extraction efficiency is poor and secondary pollution occurs
Solution Approach 1:
The patent replaces conventional mechanical/thermal treatment methods (landfill, incineration, composting) with a chemical extraction system using microwave-assisted digestion and chelating resin adsorption. This substitution enables efficient REE extraction while avoiding secondary pollution, as the chemical method selectively removes REEs without creating harmful byproducts like leachate or ash.
Solution Approach 2:
The patent introduces a chelating resin as an intermediary substance that selectively binds to and extracts REEs from the hyperaccumulator plant material. The resin acts as a mediator between the plant tissue and the extraction solution, enabling efficient REE separation while maintaining system cleanliness and preventing pollution.
2Ease of manufacture
If REE hyperaccumulators are treated by centralized landfill, then the treatment can be implemented, but seepage and heavy metal pollution occur
Solution Approach 1:
The patent converts the harmful accumulation of REEs in plant tissue (which causes pollution risks) into a beneficial resource by extracting and purifying REEs through microwave digestion and chelating resin adsorption. The REEs that would otherwise cause pollution are transformed into a valuable product, eliminating the harm while maintaining treatment feasibility.
3Adaptability or versatility
If conventional treatment methods are used, then the treatment process can be applied, but the utilization rate of enriched metals is low
Solution Approach 1:
The patent systematically extracts REEs from the hyperaccumulator plant material through microwave-assisted digestion to create a concentrated extract, then uses chelating resin to selectively adsorb and separate REEs from other metals. This extraction process achieves high utilization rates by completely recovering the enriched metals, unlike conventional methods that leave metals undutilized.
Solution Approach 2:
The patent optimizes extraction parameters including microwave power (1000-1500 W), digestion time (10-20 min), pH level (4.5-5.5), and resin contact time to maximize REE recovery. These parameter optimizations enable high utilization rates while maintaining broad applicability to different REE hyperaccumulator species.
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 effectively extracts REEs with an extraction rate of over 85% and achieves high-purity rare earth oxides, preventing secondary pollution and reducing production costs, while enhancing the utilization of REE hyperaccumulators.
Implementation Method 1
adding a digestion solution to the plant tissue pulp followed by microwave-assisted digestion to obtain a REE extract
Implementation Method 2
rare earth elements are absorbed and separated via a chelating resin
Implementation Method 3
feeding a 10-30 wt. % oxalic acid solution to the secondary purified rare earth solution under stirring to form a rare earth oxalate precipitate
Implementation Method 4
drying and calcination at 650-900° C. for 50-90 min to obtain a rare earth oxide
Data Source
AI summary
A method for extracting rare earth elements (REEs) from a REE hyperaccumulator, including: subjecting the REE hyperaccumulator to microwave-assisted digestion to obtain a REE extract; subjecting the REE extract to absorption with a chelating resin and elution to obtain a purified REE solution; and subjecting the purified REE solution to precipitation and calcination to obtain high-purity rare earth compound.