Acid-Deficient Uranyl Nitrate Preparation via Microwave Hydrolysis
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Solution Overview
Problem
The preparation of acid-deficient uranyl nitrate solutions under high uranium concentrations is slow due to slow uranium oxide hydrolysis reactions, requiring extended periods of time.
Innovation Solution
A method involving dissolving uranium oxide in aqueous nitric acid, applying pressure and heat in a sealed reaction chamber, and gradually reducing pressure and temperature to produce an acid-deficient uranyl nitrate solution with specific uranium and nitrate ion concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uranium oxide hydrolysis is performed under acid-deficient conditions at high uranium concentrations, then the desired acid-deficient uranyl nitrate solution is produced, but the reaction takes an extended period of time
Solution Approach 1:
The patent applies parameter changes by modifying temperature (heating to elevated temperatures), pressure (applying elevated pressure), and acid concentration (using controlled amounts of nitric acid) to accelerate the hydrolysis reaction. These parameter changes enable the reaction to proceed faster while still achieving the desired acid-deficient conditions, thus resolving the contradiction between manufacturing precision and productivity.
Solution Approach 2:
The patent employs preliminary action by pre-heating the uranium oxide and nitric acid mixture to elevated temperatures before the actual hydrolysis reaction begins. This preliminary heating activates the reaction conditions, allowing the subsequent hydrolysis to proceed more rapidly while maintaining control over the acid-deficiency, thereby reducing overall preparation time without sacrificing product quality.
2Productivity
If elevated temperature and pressure are applied to accelerate hydrolysis, then preparation time is reduced, but energy consumption and equipment complexity increase
Solution Approach 1:
The patent applies partial or excessive action by using elevated temperatures and pressures that are higher than standard conditions to dramatically accelerate the reaction rate. While this does increase energy consumption, the treatment is applied only for the duration necessary to achieve rapid hydrolysis, after which the system is cooled and depressurized. This approach accepts temporary excessive energy input to gain significant productivity improvement.
Solution Approach 2:
The patent employs periodic action through a multi-stage process: heating to elevated temperature and pressure for a specific hold time to accelerate reaction, then cooling and depressurizing. This periodic cycling between high-energy and low-energy states allows the system to achieve rapid reaction kinetics when needed while minimizing overall energy consumption by returning to ambient conditions afterward.
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 significantly reduces the preparation time of acid-deficient uranyl nitrate solutions to less than six hours, achieving desired uranium concentrations and pH ranges, while maintaining solution stability and efficiency.
Implementation Method 1
heating the uranium solution to a desired holding temperature of between 150° C. and 250° C. by applying microwave energy or an electric heater to the uranium solution
Implementation Method 2
heating the uranium solution to a desired holding temperature of between 150° C. and 250° C. by applying microwave energy or an electric heater to the uranium solution
Implementation Method 3
placing the uranium solution under a pressure greater than atmospheric pressure, a pressure of 5 to 40 atmospheres, a pressure of 5 to 20 atmospheres, or a pressure of 10 to 40 atmospheres in a sealed reaction chamber
Implementation Method 4
dissolving a uranium oxide, e.g., UxOz in aqueous nitric acid to produce a uranium solution
Data Source
AI summary
A solution of acid deficient uranyl nitrate has a formula of UO2(OH)y(NO3)2-y, where y ranges from 0.1 to 0.5. The solution is prepared by placing UxOz in aqueous nitric acid to produce a uranium solution, wherein x is 1 to 3 and z is 2 to 8; placing the uranium solution under a pressure greater than atmospheric pressure in a sealed reaction chamber; and heating the uranium solution to a desired temperature of between 150° C. and 250° C. by applying microwave energy to the uranium solution. The uranium solution is maintained at the desired temperature under a pressure of from 5 atmospheres to 40 atmospheres for a hold time of 15 minutes to 6 hours to produce the desired acid deficient uranyl nitrate.