Iron-Selective Solid Phase Extraction for Metal Recycling Streams
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Solution Overview
Problem
Current methods for recycling valuable metals from process streams contaminated with iron, such as battery cathode recycling streams, are inefficient and costly due to the strong adsorption of iron by solid phase extractants, which requires the use of concentrated acids for elution, leading to resin poisoning and inefficient iron removal.
Innovation Solution
The use of a solid phase extraction method involving aminomethylphosphonic acid (AMPA) combined with ethylenediaminetetraacetic acid (EDTA) as a stripping agent to selectively adsorb and desorb iron from the solid phase extractants, avoiding the need for concentrated acids and enabling efficient iron removal without degrading the solid phase media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If concentrated acids are used to elute iron from solid phase extractants, then iron removal efficiency is improved, but resin poisoning and degradation occur
Solution Approach 1:
The invention changes the chemical parameters of the elution process by using EDTA (a chelating agent) instead of concentrated acids. This parameter change allows effective iron removal through chelation while maintaining resin stability, resolving the contradiction between iron removal efficiency and resin durability
Solution Approach 2:
EDTA acts as an intermediary substance that mediates between the iron-bound resin and the elution process. The chelating agent forms a stable complex with iron, enabling iron release from the resin without requiring harsh acidic conditions that would degrade the resin
2Manufacturing precision
If multiple separate extraction steps using different solvent extractants are used, then metal separation purity is improved, but process complexity and cost increase
Solution Approach 1:
The solid phase extractant is designed to perform multiple functions: selective iron adsorption from complex process streams, and subsequent iron elution using a universal chelating agent (EDTA). This multi-functionality eliminates the need for multiple separate extraction steps with different extractants, simplifying the overall process while maintaining separation purity
Solution Approach 2:
The invention extracts and removes iron specifically from process streams containing valuable metals, taking out the problematic impurity without requiring complex multi-step procedures. The solid phase extractant selectively binds iron, which is then removed in a single elution step using EDTA
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 approach allows for the efficient and cost-effective recovery of valuable metals by selectively removing iron from process streams, making the recycling process more economical and sustainable, with EDTA being non-toxic and soluble in water, reducing material costs and environmental impact.
Implementation Method 1
contacting the acidic aqueous recycling feed with a solid phase extractant material which adsorbs the iron
Implementation Method 2
recovering the iron from the solid phase extractant material by contacting the solid phase extractant material with a stripping agent comprising a solution of organic chelating molecules which form a complex with the iron
Data Source
AI summary
A method of recycling one or more valuable metal elements from a source material comprising the one or more valuable metal elements, the method comprising: forming an acidic aqueous recycling feed by acid leaching the source material or a derivative thereof, the acidic aqueous recycling feed comprising the one or more valuable metal elements and iron in solution; contacting the acidic aqueous recycling feed with a solid phase extractant material which adsorbs the iron, the one or more valuable metal elements remaining in solution; recovering the one or more valuable metal elements from the acidic aqueous recycling feed via one or more further process steps selected from solvent extraction, solid phase extraction, electrochemical extraction, and precipitation processes; and recovering the iron from the solid phase extractant material by contacting the solid phase extractant material with a stripping agent comprising a solution of organic chelating molecules which form a complex with the iron.