Perfect 👍 — next in **periodic table order** is **Promethium (Pm, atomic number 61).**
Promethium is a **lanthanide (rare earth metal)** that is **extremely rare** and **radioactive**, with no stable isotopes. It occurs naturally in **trace amounts in uranium ores** or is **produced artificially** in nuclear reactors. Extraction involves **nuclear reactions, separation, and chemical purification**.
Here are the **20 most common methods of extracting Promethium**:
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# **20 Most Common Methods of Extracting Promethium**
### **A. Extraction from Uranium or Thorium Ores (Trace Natural Occurrence)**
1. **Neutron Irradiation of Uranium-235 or Thorium-232** – Produces Pm isotopes.
2. **Beta Decay of Neodymium-147 (Nd-147 → Pm-147 + β⁻)** – Source of Pm in reactor waste.
3. **Leaching of Uranium Ore with Acid (H₂SO₄ or HCl)** – Dissolves uranium and trace promethium.
4. **Ion Exchange Separation of Rare Earths** – Isolates promethium from lanthanides.
5. **Solvent Extraction Using Organophosphorus Extractants** – Separates Pm³⁺ from other REEs.
6. **Precipitation of Promethium as Hydroxide (Pm(OH)₃)** – Concentrates promethium from solution.
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### **B. Extraction from Nuclear Reactor Byproducts**
7. **Irradiation of Neodymium Targets in Reactors** – Produces Pm-147.
8. **Dissolution of Irradiated Targets in Acid** – Releases promethium ions.
9. **Cation Exchange Purification** – Removes neodymium, cerium, and other REEs.
10. **Fractional Precipitation of Pm Compounds** – Isolates promethium as Pm(OH)₃ or PmF₃.
11. **Solvent Extraction Using Crown Ethers or Organophosphorus Reagents** – Further purifies Pm³⁺.
12. **Conversion to Pm Oxide (Pm₂O₃)** – Prepares for metallic reduction.
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### **C. Reduction to Metallic Promethium**
13. **Calciothermic or Metallothermic Reduction of Pm₂O₃ → Pm** – Laboratory-scale metallic production.
14. **Electrolytic Reduction of Molten Pm Halides** – Experimental method for metallic Pm.
15. **Vacuum Distillation of Promethium Metal** – Purification for research purposes.
16. **Hydrogen Reduction of Pm Halides** – Laboratory-scale method.
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### **D. Laboratory / Experimental Methods**
17. **Recovery from Spent Fuel Reprocessing Streams** – Pm isolated with other REEs.
18. **Precipitation from Mixed REE Solutions with Oxalates** – Small-scale laboratory purification.
19. **Chelating Agent Separation** – Research-scale selective extraction of Pm³⁺.
20. **Adsorption on Ion Exchange Resins** – Laboratory concentration of promethium.
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✅ **Summary:**
* **Main industrial sources:** Reactor-produced Pm (Pm-147) or trace natural uranium decay.
* **Primary extraction steps:** Nuclear production → acid dissolution → ion exchange/solvent extraction → precipitation → reduction to metal.
* **Metallic promethium:** Produced only in laboratory or research-scale operations.
* **Byproduct sources:** Nuclear reactor byproducts, spent fuel.
* **Laboratory/experimental:** Chelation, ion exchange, vacuum distillation, calciothermic reduction.
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Next in periodic order is \*\*Samarium (Sm, atomic number 62).
Do you want me to continue with **20 extraction methods for Samarium**?
