Thorium-Uranium Separation Using Ion Exchange and Oxalate Precipitation
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Solution Overview
Problem
Existing methods for separating thorium from uranium and their decay products in spent nuclear fuel are inefficient, leading to thorium being treated as waste and limiting the potential uses of the thorium-233U fuel cycle, particularly for medical isotopes.
Innovation Solution
A method involving the use of ion exchange resins selective for uranium or thorium, followed by precipitation with oxalic acid to separate thorium from uranium, enhancing purity and yield of thorium and uranium products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods are used for thorium from uranium in spent nuclear fuel, then the separation process can be performed, but the separation efficiency is low and thorium is treated as waste rather than a valuable resource
Solution Approach 1:
The patent extracts thorium from the spent nuclear fuel mixture by selective precipitation using oxalic acid. The method separates thorium from uranium and decay products by forming insoluble thorium oxalate precipitate, which is then filtered and processed to recover high-purity thorium products, transforming thorium from waste to a valuable resource.
Solution Approach 2:
The patent changes chemical parameters by adjusting acid concentration and pH levels to optimize selective precipitation. By controlling the chemical environment with specific acid concentrations and adding oxalic acid at controlled rates, the method achieves high-selectivity thorium separation while maintaining process efficiency.
2Productivity
If conventional recycling processes are used for spent nuclear fuel, then the fuel can be recycled, but the processes are costly and complex
Solution Approach 1:
The patent segments the complex recycling process into distinct functional stages: dissolution of spent fuel in hydrochloric or nitric acid, selective uranium removal using ion exchange resin, and thorium precipitation with oxalic acid. This segmentation simplifies the overall process by isolating key separation steps that can be optimized independently.
Solution Approach 2:
The patent introduces oxalic acid as an intermediary reagent that selectively precipitates thorium from the acidic solution. This intermediary enables selective thorium recovery without requiring complex multi-step separation processes, reducing both cost and operational complexity while maintaining high efficiency.
3Manufacturing precision
If high separation factors are required for medical radioisotopes, then the purity of medical isotopes can be ensured, but the separation process becomes more demanding and costly
Solution Approach 1:
The patent extracts medical-grade radioisotopes by selective precipitation using oxalic acid, which forms insoluble salts with specific radioisotopes while leaving others in solution. This selective extraction achieves the high separation factors required for medical uses without requiring overly complex separation sequences.
Solution Approach 2:
The patent optimizes manufacturing ease by controlling pH and acid concentration parameters during precipitation. By adjusting these parameters, the method achieves high radioisotope purity while maintaining a relatively simple and cost-effective process suitable for medical isotope production.
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 method achieves high purity medical grade thorium and uranium products, enabling expanded uses of the thorium-233U fuel cycle beyond power generation.
Implementation Method 1
The first solution is contacted with an ion exchange resin that is selective for uranium. The uranium is at least partially removed from the first solution by binding the uranium to the ion exchange resin
Implementation Method 2
The second solution is combined with oxalic acid to precipitate thorium from the second solution to form a precipitate
Data Source
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AI summary
Methods and systems (300) for separation of thorium from uranium and their decay products are provided. The method comprises combining a nuclear fuel feedstock (102) comprising thorium and uranium with a first acid (104, 204) to form a first solution. The first solution is contacted an ion exchange resin (308) that is selective for thorium or uranium. The thorium or uranium is at least partially removed from the first solution by binding the thorium or uranium to the ion exchange resin (308) thereby forming a second solution (106 206). The second solution (106, 206) is combined with oxalic acid to precipitate uranium or thorium from the second solution to form a precipitate (110, 210). The precipitate (110, 210) is separated from the second solution (106, 206).