Ra-226 Target Purification by Acid Distillation and Cold Precipitation
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Solution Overview
Problem
Existing methods for purifying irradiated targets for re-use in radio-isotope production are inefficient and fail to address issues such as limited solubility, impurity removal, and pH uncertainties, particularly for liquid targets like Ra-226, which are crucial for producing radio-isotopes like Ac-225.
Innovation Solution
A method involving the use of HNO3 acid at specific concentrations and temperatures to dissolve irradiated target materials, followed by evaporation and temperature reduction to precipitate the target material, separating it from radio-isotopes and impurities, and preparing it for re-use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If solid targets are used for radio-isotope production, then high yield is achieved, but the target material cannot be reused
Solution Approach 1:
The patent recovers the target material (Ra-226) from the irradiated solution through precipitation and filtration processes, allowing it to be reused in subsequent irradiations. This resolves the contradiction by recovering the target material that would otherwise be discarded after single-use irradiation.
Solution Approach 2:
The patent changes the physical state of the target material from solid to dissolved form in liquid target solution, enabling reuse. By controlling solubility parameters and using chelating agents, the target material can be maintained in solution form across multiple irradiation cycles.
2Loss of substance
If liquid targets are used to overcome limited solubility, then re-use is enabled, but solubility limitations remain
Solution Approach 1:
The patent uses chelating agents as intermediaries to complex with the target material (Ra-226), enabling it to remain in solution at higher concentrations than naturally soluble. The chelating agent acts as a mediator that increases the effective solubility of the target material.
Solution Approach 2:
The patent creates composite chemical systems combining the target material with chelating agents and other chemical compounds to form soluble complexes. This composite approach overcomes the inherent solubility limitations of pure Ra-226 salt solutions.
3Loss of substance
If purification is performed to enable re-use, then target material can be recycled, but process complexity increases
Solution Approach 1:
The patent segments the purification process into distinct functional steps: dissolution, chelation, precipitation, and filtration. Each step handles a specific separation task, making the overall complex purification process more manageable and systematic.
Solution Approach 2:
The patent employs self-service separation mechanisms where the target material automatically precipitates from the solution based on its chemical properties, eliminating the need for complex external separation equipment. The system uses the material's inherent characteristics to achieve purification.
4Quantity of substance
If acid is added to dissolve target material, then complete dissolution is achieved, but co-precipitation of radio-isotopes occurs
Solution Approach 1:
The patent carefully controls pH parameters and acid concentration to optimize dissolution while preventing co-precipitation. By adjusting these parameters, the system achieves complete dissolution of the target material without causing unwanted precipitation of radio-isotopes.
Solution Approach 2:
The patent employs dynamic control of acid addition and pH adjustment during the dissolution process. The system adapts the acid concentration and addition rate in real-time to maintain optimal conditions for dissolution while preventing co-precipitation, rather than using fixed static parameters.
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 efficient re-use of irradiated targets by minimizing impurities and reducing solubility, allowing increased production of radio-isotopes like Ac-225 with reduced complexity and loss of Ra-226.
Implementation Method 1
adding an acid being HNO3 in a predetermined quantity and concentration and providing conditions for quantitatively dissolving the target material
Implementation Method 2
selectively removing H2O from the solution by evaporation
Implementation Method 3
lowering the temperature of the solution to maximise the precipitation of the target material and reduce the solubility of the target material in the remaining liquid
Implementation Method 4
separating the liquid containing the optionally present radio-isotopes and/or impurities from the precipitated target material
Data Source
AI summary
A method for purification of a target material for re-use in the production of radio-isotopes is disclosed, and includes obtaining a solution of irradiated target material, comprising Ra-226 and optionally Ra-225 and Ac-225, and subsequently adding an acid, being HNO3, in a predetermined quantity and providing conditions for quantitatively dissolving the target material and avoiding co-precipitation of the optionally present radio-isotopes. The method includes selectively removing H2O from the solution by distillation, leaving the acid predominantly inside the solution thereby allowing the target material to precipitate while the acid concentration in the solution increases and thereby reducing or avoiding co-precipitation of the optionally present radio-isotopes and impurities. After removal of the excess H2O, the method comprises lowering the temperature of the solution to maximize the precipitation of the target material and reduce the solubility of the target material in the remaining liquid.