Diglycolamic Acid Adsorbent for Selective Rare Earth Recovery
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Solution Overview
Problem
Current adsorbents lack selectivity for rare earth elements in low-acid solutions, particularly in the presence of base metal ions, and are not suitable for repeated use, leading to inefficient recovery and high costs in processing dilute solutions.
Innovation Solution
Introducing diglycolamic acid into a base material, such as silica gel or polymer particles, to create an adsorbent that maintains high selectivity and adsorption rate, even in low pH conditions, and allows for easy desorption and repeated use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If commercially available adsorbents (ion-exchange resins, chelate resins) are used, then adsorption capacity is achieved, but selectivity to rare earth elements deteriorates due to co-adsorption of iron (III) ions
Solution Approach 1:
The patent changes the chemical parameter of the adsorbent by introducing diglycolamic acid functional groups, which have specific coordination chemistry properties that differentiate their binding affinity for rare earth elements versus iron ions. This chemical parameter change enables selective adsorption based on the unique coordination preferences of rare earth elements.
Solution Approach 2:
The patent creates a composite adsorbent material combining diglycolamic acid functional groups with a support matrix. This composite structure integrates the selective binding capability of diglycolamic acid with the mechanical stability and surface area of the support material, achieving both selectivity and adsorption capacity.
2Manufacturing precision
If precipitation method with alkali is used to remove iron, then iron removal is achieved, but process complexity and cost increase due to poor filterability and large alkali requirement
Solution Approach 1:
The patent extracts the iron removal function from the separate precipitation process and integrates it into the adsorption step. The diglycolamic acid-based adsorbent selectively extracts iron ions from the solution during the same operation used to recover rare earth elements, eliminating the need for a separate precipitation and filtration process.
Solution Approach 2:
The diglycolamic acid functional groups act as an intermediary that facilitates selective binding of iron ions through specific coordination chemistry. This intermediary mechanism enables iron removal without requiring alkali addition and subsequent precipitation, simplifying the overall process.
3Quantity of substance
If adsorbents requiring weakly acidic region (polymer-based, organism-derived, iminodiacetic acid chelate resins) are used, then adsorption ability is achieved, but additional cost is incurred due to pH adjustment pretreatment
Solution Approach 1:
The patent changes the pH parameter requirement by designing an adsorbent with diglycolamic acid functional groups that maintain their adsorption capability in low pH conditions. This parameter change eliminates the need for pH adjustment pretreatment while preserving adsorption ability.
4Manufacturing precision
If solvent extraction method is used, then separation performance is improved, but facility scale and investment cost increase due to requirement of large-scale facilities
Solution Approach 1:
The patent replaces the mechanical solvent extraction system with a solid-phase adsorption system. Instead of using large-scale liquid-liquid extraction equipment, the invention uses compact adsorbent materials that can be implemented in smaller, more flexible configurations while achieving comparable or superior separation performance.
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
The adsorbent effectively selectively recovers rare earth elements from dilute solutions with high selectivity and adsorption capacity, even in the presence of base metals, and can be reused multiple times, significantly improving the efficiency and cost-effectiveness of the recovery process.
Implementation Method 1
an adsorbent for rare earth element which is located in an aqueous phase and brought into contact with an aqueous solution containing a rare earth element to adsorb and recover the rare earth element
Implementation Method 2
diglycolamic acid introduced into the base material
Data Source
AI summary
An adsorbent for rare earth element and a method for recovering a rare earth element, in which a rare earth element contained in an aqueous solution can be simply and inexpensively adsorbed and recovered, and a rare earth element present in an aqueous solution in combination with a base metal can be selectively adsorbed and recovered. The adsorbent includes a base material and diglycolamic acid introduced into the base material. The method for recovering a rare earth element includes steps of: bringing an aqueous solution containing a rare earth element into contact with the adsorbent for rare earth element to allow the rare earth element to be adsorbed on the adsorbent for rare earth element; and desorbing the rare earth element adsorbed on the adsorbent for rare earth element with an acid of 1 N or less.