Ionic Liquid Extraction of Rare Earths From Coal Ash
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Solution Overview
Problem
Existing methods for recovering rare earth elements (REEs) from coal fly ash are hazardous, energy-intensive, and result in impure mixtures requiring further separation processes, as they use highly corrosive solutions like HF and H2O2, which digest both REEs and bulk elements.
Innovation Solution
A method using alkaline components and ionic liquids to form immiscible and miscible mixtures at specific temperatures and pH levels, allowing selective extraction of REEs while leaving bulk elements behind, followed by adjusting pH and temperature to isolate the ionic liquid and extract metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If highly corrosive solutions like HF and H2O2 are used to digest REEs from coal fly ash, then REE recovery is achieved, but the process becomes hazardous, energy-intensive, and produces impure mixtures requiring further separation
Solution Approach 1:
The patent changes the chemical parameters by replacing highly corrosive solutions (HF, H2O2) with ionic liquids that have different chemical properties. The ionic liquid system operates under milder conditions with adjustable pH and temperature, achieving REE extraction without the harmful effects of traditional reagents while maintaining effectiveness.
Solution Approach 2:
The patent introduces an intermediary system consisting of ionic liquid and aqueous component that mediates the extraction process. This intermediary system selectively binds to REEs through complexation, enabling separation from bulk elements without direct contact with harsh chemicals, thus reducing hazards and energy requirements.
2Reliability
If highly corrosive solutions are used to extract REEs, then REEs are digested along with bulk elements, but this results in impure mixtures requiring further separation processes
Solution Approach 1:
The patent applies local quality by designing the ionic liquid with specific functional groups that have selective affinity for REEs. This selective complexation occurs locally at the molecular level, allowing REEs to be extracted while bulk elements remain in the aqueous phase, achieving both high extraction efficiency and purity in a single step.
Solution Approach 2:
The patent segments the extraction process into two distinct phases: an ionic liquid phase that selectively binds REEs and an aqueous phase that contains bulk elements. This phase separation enables selective recovery of REEs with high purity, eliminating the need for additional separation processes.
3Reliability
If traditional methods are used for REE recovery, then the process is complex and multi-stage, but this increases device complexity and operational difficulty
Solution Approach 1:
The patent merges multiple functions into a single extraction system. The ionic liquid simultaneously performs extraction, separation, and purification of REEs in one operation, replacing the traditional multi-stage process that required separate steps for digestion, extraction, and purification, thus reducing device and process complexity.
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 efficiently and selectively extracts REEs from coal fly ash using safer materials and energy-efficient techniques, reducing the need for further separation processes and minimizing environmental hazards.
Implementation Method 1
forming a first multicomponent system having an ionic liquid and a first aqueous component. The first aqueous component and the ionic liquid can form an immiscible mixture when the first multicomponent system is at a temperature below a first critical temperature and/or at a pH above a critical pH value.
Implementation Method 2
Adjusting the temperature of the first multicomponent system above the first critical temperature and/or the pH of the first multicomponent system above the critical pH value can form a miscible mixture with the ionic liquid and the first aqueous component.
Data Source
AI summary
An exemplary embodiment of the present disclosure provides a method to extract components from a metal-containing material, forming a first multicomponent system comprising an ionic liquid and a first aqueous component, wherein the first aqueous component and the ionic liquid form an immiscible mixture when the first multicomponent system is at a temperature below a critical temperature, contacting a metal-containing material with the first multicomponent system, adjusting the temperature of the first multi-component system above the first critical temperature to form a miscible mixture with the ionic liquid and the first aqueous component, reverting the temperature of the first multicomponent system below the critical temperature to form an immiscible mixture with the ionic liquid and the first aqueous component, and isolating the ionic liquid from the first aqueous component and the metal-containing material, wherein the ionic liquid comprises one or more metals from the metal-containing material.