LDH Intercalation for Selective Uranium Separation
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Solution Overview
Problem
Current methods for separating uranium from mixtures containing other metals and rare earth elements in aqueous streams are inefficient, often resulting in uranium being difficult to isolate due to the presence of impurities and other commodities, which complicates further processing and purification.
Innovation Solution
The process involves forming layered double hydroxide (LDH) materials in situ within the aqueous solution, where uranium forms complex anions that are intercalated into the LDH's interlayers, while other metals are incorporated into the crystal structure, allowing for selective recovery of uranium through subsequent treatment steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional leaching processes are used to extract uranium from ores, then uranium can be obtained from the ore, but uranium becomes difficult to separate from other commodities and impurities such as rare earth elements
Solution Approach 1:
The invention segments the co-precipitation process into two distinct mechanisms: (1) incorporation of cationic metals into the LDH crystal structure, and (2) intercalation of complex anions into the LDH interlayers. This segmentation allows selective recovery of uranium (as complex anion) from other metals (as cations in crystal structure), resolving the separation difficulty while maintaining extraction efficiency
Solution Approach 2:
The LDH material acts as an intermediary that differentiates between cationic and anionic species in the aqueous stream. By forming complex anions with uranium while other metals remain as cations, the LDH selectively incorporates them into different structural positions, enabling subsequent selective recovery of uranium without contamination from other commodities
2Productivity
If aqueous streams contain multiple metals and metalloids as both commodities and contaminants, then comprehensive metal extraction can be achieved, but the presence of problematic cations and anions complicates subsequent element extraction and purification
Solution Approach 1:
The invention segments metals into two categories based on their chemical behavior: cationic metals (incorporated into LDH crystal structure) and anionic complex-forming metals (intercalated into LDH interlayers). This segmentation simplifies the purification process by enabling selective recovery of the anionic component (uranium) in a single step, reducing the complexity of subsequent processing
Solution Approach 2:
The invention changes the chemical parameter of uranium from cationic form to complex anion form through controlled complexation. This parameter change allows uranium to be selectively intercalated into the LDH interlayers while other metals remain as cations in the crystal structure, simplifying subsequent separation and purification steps
3Manufacturing precision
If layered double hydroxide is used to selectively separate uranium as complex anions from cationic metals, then uranium enrichment can be achieved, but the process requires formation of complex anions and specific pH conditions
Solution Approach 1:
The invention utilizes pH as a controllable parameter to regulate complex anion formation. By maintaining specific pH conditions, uranium forms stable complex anions that can be selectively intercalated into LDH, while other metals remain as cations. This parameter control enables high selectivity without requiring complex process conditions
Solution Approach 2:
The invention employs LDH as a composite material with specific structural characteristics (positively charged layers and interlayer spaces). This composite structure provides both the crystal structure for cation incorporation and the interlayer space for anion intercalation, enabling selective separation based on the dual-mechanism approach
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 enrichment of uranium and rare earth elements by 100-300 times compared to typical ore grades, effectively separating uranium from other metals and impurities, resulting in a cleaner effluent that can be reused in mineral processing without additional treatment.
Implementation Method 1
contacting the solution with one or more additives to form layered double hydroxide (LDH) material in situ such that the complex anion is intercalated within interlayers of the LDH material
Implementation Method 2
LDH is most commonly formed by the co-precipitation of divalent (e.g. Mg2+, Fe2+) and trivalent (e.g. Al3+, Fe3+) metal cation solutions at moderate to high pH
Implementation Method 3
LDH is a class of both naturally occurring and synthetically produced materials characterised by a positively-charged mixed metal hydroxide layers separated by interlayers that contain water molecules and a variety of exchangeable anions
Data Source
AI summary
A process for selectively separating a metallic constituent from other metals and other materials accompanying the metallic constituent in a mixture is described. The process comprises the step of providing the mixture in an aqueous solution such that the metallic constituent forms a complex anion in the solution. One or more of the other metals forms a cation or a complex cation in the solution. Another step includes contacting the solution with one or more additives to form layered double hydroxide (LDH) material in situ such that the complex anion is intercalated within interlayers of the LDH material and wherein one or more of the other metals are incorporated into the LDH material's crystal structure or matrix. Another step involves the addition of an LDH to an aqueous solution. The process involves selectively recovering the metallic constituent from the interlayer of the LDH by subjecting the LDH to a recovery treatment step(s) and as required, methods to modify the LDH to facilitate metal separation and recovery or contaminant stabilisation.