Uranyl Nitrate Precipitation with Recirculating Base Recovery
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Solution Overview
Problem
Unreacted metal nitrate salts, particularly those of heavy metals and radioactive metals, remain in supernatants after sol-gel reactions, posing environmental pollution and handling challenges due to their toxicity and regulatory restrictions on disposal.
Innovation Solution
A method and system involving a formation column with a recirculating base solution to precipitate metal oxides or hydroxides, capturing the precipitate in a basket, and processing it through washing and drying to convert it into usable metal oxides, utilizing ammonia, ammonium hydroxide, or other hydroxides as bases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If uranyl nitrate solution is treated with base to generate insoluble uranate precipitate, then uranium recovery is achieved, but the precipitate has viscid properties causing material handling challenges and loss
Solution Approach 1:
The patent changes the chemical parameters of the precipitation process by controlling pH, temperature, and base addition rate to produce uranate precipitates with improved physical properties. By optimizing these parameters, the precipitate transitions from a viscid, hard-to-handle form to a more free-flowing solid that can be easily transferred and processed, thereby reducing material loss while maintaining effective uranium recovery
Solution Approach 2:
The patent utilizes phase transition of the uranate precipitate from a viscid semi-solid state to a free-flowing solid state through controlled drying and heating processes. This phase change eliminates the handling difficulties associated with viscid materials, allowing the precipitate to be easily transferred between vessels and processed further with minimal material loss
2Loss of substance
If ammonia or ammonium hydroxide is used to precipitate ammonium diuranate, then uranium is recovered from waste solution, but substantial material is left behind in vessels requiring difficult cleanout operations
Solution Approach 1:
The patent modifies the precipitation parameters by adjusting the base concentration, addition rate, and reaction temperature to control the morphology and adhesion properties of the uranate precipitate. These parameter changes result in a precipitate that forms as discrete particles rather than adhering strongly to vessel surfaces, thereby eliminating the need for difficult cleanout operations while maximizing uranium recovery
Solution Approach 2:
The patent employs a recirculating slurry system where the precipitate is continuously circulated and processed, creating a self-cleaning effect that prevents material buildup on vessel surfaces. This approach replicates the ideal of complete material transfer without requiring manual cleanout operations
3Productivity
If unreacted nitrate salts are disposed of after sol-gel reaction, then the process is simple, but environmental pollution and toxicity issues arise
Solution Approach 1:
The patent implements a recovery process that transforms the disposal problem into a resource recovery opportunity. By treating the nitrate-containing supernatant with base to precipitate uranate, the process recovers valuable uranium from what would otherwise be waste, converting a harmful disposal issue into a productive recovery operation that eliminates environmental pollution while maintaining operational efficiency
Solution Approach 2:
The patent converts the harmful aspect of nitrate waste into a beneficial recovery opportunity. The nitrate-containing solution, initially considered waste requiring disposal, becomes the feedstock for uranium recovery through base precipitation. This transformation eliminates environmental pollution concerns while generating a valuable uranium product, turning a harmful waste stream into a beneficial resource
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
Effectively recovers and reuses valuable metals from waste nitrate solutions, reducing environmental pollution and enabling safe handling and conversion of toxic nitrate salts into useful metal oxides.
Implementation Method 1
The uranyl nitrate is allowed to react with the base in the recirculating solution to produce a diuranate salt as a precipitate
Implementation Method 2
allowing the nitrate salt in the solution to react with the base in the recirculating solution to produce a metal oxide salt or a metal hydroxide salt as a precipitate
Implementation Method 3
capturing the precipitate in a basket beneath the formation column while recovering the recirculating solution
Implementation Method 4
processing it through washing and drying to convert it into usable metal oxides
Data Source
AI summary
A useful metal may be recovered from a solution of a nitrate salt of a metal cation or a metal oxycation, by adding the solution of the nitrate salt to a formation column having an inlet and an outlet nozzle, the solution of the nitrate salt being added in a dropwise fashion through the inlet. The formation column contains a recirculating solution containing a base selected from the group consisting of ammonia, ammonium hydroxide, an alkali metal hydroxide, and an alkaline earth metal hydroxide. The nitrate salt reacts with the base in the recirculating solution to produce a metal oxide salt or a metal hydroxide salt as a precipitate. The precipitate and the recirculating solution exit the formation column through the outlet nozzle and are captured the precipitate in a basket beneath the formation column while recovering the recirculating solution in a catch tank under the basket. The recovered recirculating solution is pumped from the catch tank to the formation column. The nitrate salt of the metal cation may be a nitrate salt of a radioactive metal cation, e.g., uranium or a uranyl cation.