Great — now we’re on **Neptunium (Np, atomic number 93).**
Neptunium is a **synthetic radioactive actinide**, discovered in 1940. It does **not occur naturally in significant quantities** (only trace amounts from uranium decay), so nearly all neptunium is produced **artificially in nuclear reactors**. Its isotopes, especially ^237Np, are used in **nuclear science**, as a precursor for plutonium production, and in some **radioisotope power sources**.
Here are the **20 most common methods of extracting Neptunium**:
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# **20 Most Common Methods of Extracting Neptunium**
### **A. Reactor-Based Production**
1. **Neutron Capture on Uranium-235 (^235U(n,γ)^236U → β decay → ^237Np)** – Standard production method.
2. **Neutron Capture on Uranium-238 (^238U(n,γ)^239U → β decay → ^239Np)** – Produces ^239Np for short-term research.
3. **Irradiation of Plutonium-238 in Reactors** – Produces minor neptunium isotopes.
4. **Breeding from Thorium Fuel Cycle** – Trace neptunium formation in experimental reactors.
5. **Fast-Neutron Irradiation of Uranium Targets** – Increases neptunium yield for research.
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### **B. Recovery from Spent Nuclear Fuel**
6. **Dissolution of Spent Uranium/Plutonium Fuel in Nitric Acid** – Releases neptunium into solution.
7. **Separation from Plutonium and Uranium by Solvent Extraction** – PUREX-like processes.
8. **Ion Exchange Separation** – Cation or anion exchange to isolate Np.
9. **Selective Precipitation (Np(OH)₄, NpO₂)** – Exploits solubility differences.
10. **Solvent Extraction with TBP / D2EHPA** – Industrial radiochemistry method.
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### **C. Laboratory & Radiochemical Techniques**
11. **Electrodeposition of Np on Platinum/Gold Electrodes** – Produces high-purity samples.
12. **Co-precipitation with Lanthanide Carriers** – Removes Np from fission products.
13. **Chromatography Using Silica Gel or Ion Exchange Resins** – Lab purification.
14. **Extraction as Neptunium Fluoride (NpF₄)** – Volatile intermediate for separation.
15. **Extraction as Neptunium Oxalate (Np₂(C₂O₄)₄)** – Classical purification technique.
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### **D. Specialized & Advanced Methods**
16. **Oxidation State Adjustment (Np³⁺, Np⁴⁺, NpO₂⁺)** – Facilitates selective separation.
17. **Anion-Exchange in Nitric/Perchloric Acid Media** – Exploits NpO₂⁺ complex chemistry.
18. **Liquid–Liquid Extraction in Mixed Acid Systems** – Lab-scale enrichment.
19. **Micro-precipitation Techniques** – For small amounts used in experiments.
20. **Automated Radiochemical Separation Loops** – Modern reactor facilities produce Np with minimal radiation exposure.
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✅ **Summary:**
* Neptunium is **almost entirely synthetic**, primarily from **uranium irradiation in reactors**.
* Separation from spent fuel involves **acid dissolution**, **solvent extraction**, and **ion exchange**, sometimes using **oxidation-state control**.
* Applications are mainly in **nuclear science**, **plutonium production**, and **radioisotope power sources**.
* Only **milligram to gram quantities** are produced due to radioactivity and cost.
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Next on the periodic table is **Plutonium (Pu, atomic number 94).**
Do you want me to continue with the **20 most common methods of extracting Plutonium**?
