Perfect 👍 — next in **periodic table order** is **Gadolinium (Gd, atomic number 64).**
Gadolinium is a **lanthanide (rare earth metal)** that occurs primarily in **monazite (Ce,La,Gd,Th)PO₄** and **bastnäsite (Ce,La,Gd)(CO₃)F**. Industrial extraction involves **acid or alkaline digestion, solvent extraction, and reduction**.
Here are the **20 most common methods of extracting Gadolinium**:
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# **20 Most Common Methods of Extracting Gadolinium**
### **A. Extraction from Rare Earth Ores**
1. **Crushing and Grinding of Monazite or Bastnäsite** – Prepares ore for chemical treatment.
2. **Acid Digestion (H₂SO₄ or HCl) of Monazite** – Dissolves gadolinium and other REEs.
3. **Alkaline Digestion (NaOH) of Monazite** – Converts phosphate to soluble gadolinium salts.
4. **Leaching of Bastnäsite with Acid or Alkali** – Produces soluble gadolinium compounds.
5. **Purification by Precipitation of Thorium and Other Impurities** – Removes radioactive and heavy elements.
6. **Solvent Extraction of Gadolinium Salts** – Organophosphorus extractants separate Gd³⁺ from other REEs.
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### **B. Separation and Concentration**
7. **Ion Exchange Separation of Gadolinium** – Separates Gd³⁺ from lanthanum, cerium, praseodymium, neodymium, samarium, europium.
8. **Fractional Precipitation Using Oxalates or Hydroxides** – Concentrates gadolinium from mixed REE solutions.
9. **Conversion to Gadolinium Carbonate (Gd₂(CO₃)₃)** – Precursor for oxide formation.
10. **Calcination to Gadolinium Oxide (Gd₂O₃)** – Prepares for reduction or industrial use.
11. **Selective Solvent Extraction from Mixed REE Solutions** – Enhances separation efficiency.
12. **Chelating Agent Separation** – Laboratory or pilot-scale selective extraction.
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### **C. Reduction to Metallic Gadolinium**
13. **Calciothermic or Metallothermic Reduction of Gd₂O₃ → Gd** – Main industrial method.
14. **Electrolytic Reduction of Molten GdCl₃** – Produces high-purity metallic gadolinium.
15. **Vacuum Distillation of Metallic Gadolinium** – Purification for ultra-high purity Gd.
16. **Hydrogen Reduction of Gadolinium Halides** – Laboratory-scale method.
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### **D. Recovery from Byproducts / Secondary Sources**
17. **Recovery from Monazite Sands during Thorium Extraction** – Gadolinium collected as a byproduct.
18. **Recovery from Bastnäsite Refining** – Gd separated during extraction of other REEs.
19. **Recovery from Spent Rare Earth Catalysts** – Leaching + precipitation.
20. **Recovery from Recycled Electronics Containing REEs** – Hydrometallurgical extraction.
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✅ **Summary:**
* **Main industrial sources:** Monazite, bastnäsite.
* **Primary extraction steps:** Ore crushing → acid/alkaline digestion → purification → selective precipitation → reduction/electrolysis → metallic gadolinium.
* **Metallic gadolinium:** Produced via calciothermic/metallothermic reduction or molten salt electrolysis.
* **Byproduct sources:** Thorium extraction residues, bastnäsite processing, spent REE catalysts, recycled electronics.
* **Laboratory/experimental:** Ion exchange, selective solvent extraction, vacuum distillation, hydrogen reduction.
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Next in periodic order is \*\*Terbium (Tb, atomic number 65).
Do you want me to continue with **20 extraction methods for Terbium**?
