Perfect 👍 — next in **periodic table order** is **Cadmium (Cd, atomic number 48).**
Cadmium is a **transition metal** that does **not occur free** in nature. It is primarily obtained as a **byproduct of zinc, lead, and copper ore refining**, especially from **sphalerite (ZnS)**. Extraction involves **roasting, leaching, and reduction**.
Here are the **20 most common methods of extracting Cadmium**:
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# **20 Most Common Methods of Extracting Cadmium**
### **A. Extraction from Zinc Ores**
1. **Roasting of Zinc Sulfide Ores (ZnS + O₂ → ZnO + SO₂)** – Cadmium is liberated as CdO or Cd vapor.
2. **Volatilization of Cadmium during Zinc Smelting** – CdO vaporizes and is collected from flue gases.
3. **Condensation of Cadmium Vapors** – Produces metallic cadmium.
4. **Leaching of Cadmium from Zinc Oxide Residues (H₂SO₄)** – Forms soluble cadmium sulfate.
5. **Precipitation as Cadmium Carbonate (CdCO₃)** – Intermediate purification step.
6. **Conversion of CdCO₃ → CdO by Calcination** – Prepares for reduction.
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### **B. Reduction to Metallic Cadmium**
7. **Hydrogen Reduction of CdO → Cd + H₂O** – Produces metallic cadmium.
8. **Electrolytic Reduction from CdSO₄ Solution** – Produces high-purity cadmium cathodes.
9. **Aluminothermic Reduction of CdO → Cd + Al₂O₃** – Laboratory or small-scale method.
10. **Magnesiothermic Reduction of CdO → Cd + MgO** – Experimental lab method.
11. **Carbothermic Reduction of Cd Compounds** – Specialty method.
12. **Vacuum Distillation of Cadmium Metal** – Purification of metallic Cd.
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### **C. Recovery from Byproducts / Secondary Sources**
13. **Recovery from Zinc Refinery Residues / Flue Dust** – Hydrometallurgical leaching.
14. **Recovery from Lead Refinery Byproducts** – Cd present in small quantities.
15. **Recovery from Copper Refinery Slags** – Cd extracted via acid leaching.
16. **Recovery from Recycled Batteries Containing Cd** – Dissolution + precipitation.
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### **D. Laboratory / Experimental Methods**
17. **Plasma Reduction of Cd Compounds** – High-purity experimental method.
18. **Solar-Thermal Reduction of CdO or Cd Chloride** – Experimental renewable energy method.
19. **Zone Refining of Metallic Cadmium** – Produces ultra-high purity Cd.
20. **Electroless Deposition of Cadmium from Salts** – Produces thin metallic coatings.
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✅ **Summary:**
* **Main industrial sources:** Sphalerite (ZnS) ores, zinc refinery residues.
* **Primary extraction steps:** Ore roasting → volatilization → condensation/leaching → reduction → metallic cadmium.
* **Metallic cadmium:** Produced via hydrogen, electrolytic, or metallothermic reduction.
* **Byproduct sources:** Zinc, lead, copper refining residues, recycled batteries.
* **Laboratory/experimental:** Plasma, solar-thermal, zone refining, electroless deposition.
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Next in periodic order is \*\*Indium (In, atomic number 49).
Do you want me to continue with **20 extraction methods for Indium**?
