Perfect 👍 — next in **periodic table order** is **Iridium (Ir, atomic number 77).**
Iridium is a **transition metal** that occurs primarily in **platinum group metal ores (PGMs)** such as **osmiridium**, **platinum nuggets**, and **nickel-copper sulfide ores**. Industrial extraction involves **concentration, chemical separation, and reduction**.
Here are the **20 most common methods of extracting Iridium**:
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# **20 Most Common Methods of Extracting Iridium**
### **A. Extraction from Platinum Group Ores**
1. **Mining of PGM Ores (Nickel-Copper or Platinoid Ores)** – Primary source of iridium.
2. **Crushing and Grinding of Ore** – Prepares material for concentration.
3. **Gravity and Magnetic Separation** – Enriches iridium-containing minerals.
4. **Froth Flotation** – Concentrates PGMs including Ir, Os, Pt, Rh, Ru, Pd.
5. **Smelting to Separate Base Metals** – Iridium remains in the noble metal fraction.
6. **Acid Digestion of PGM Concentrates (Aqua Regia)** – Dissolves noble metals for separation.
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### **B. Chemical Separation of Iridium**
7. **Precipitation of Iridium Chlorides (IrCl₃, IrCl₄)** – Separates Ir from other PGMs.
8. **Formation of Ammonium Hexachloroiridate ((NH₄)₂\[IrCl₆])** – Key intermediate for purification.
9. **Reduction of Iridium Salts to Metallic Iridium Powder** – Converts intermediates to elemental iridium.
10. **Ion Exchange Chromatography** – Laboratory or industrial scale purification.
11. **Solvent Extraction of Iridium Complexes** – Separates Ir from platinum, osmium, and rhodium.
12. **Selective Precipitation of Iridium Compounds** – Produces intermediates suitable for reduction.
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### **C. Conversion to Iridium Compounds**
13. **Calcination of Iridium Salts** – Removes impurities before final reduction.
14. **Preparation of Iridium Oxides (IrO₂, IrO₃)** – Intermediates for catalysis or metallic Ir.
15. **Preparation of Iridium Alloys** – Mixed with platinum, osmium, or rhodium for industrial applications.
16. **Volatilization and Condensation of Iridium Compounds** – Laboratory-scale separation from other PGMs.
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### **D. Recovery and Secondary Sources**
17. **Recovery from Platinum Refinery Residues** – Flue dusts and sludges treated for iridium.
18. **Recovery from Scrap Catalysts Containing PGMs** – Hydrometallurgical or pyrometallurgical extraction.
19. **Recovery from Nickel-Copper Smelting Slags** – Chemical leaching and selective precipitation.
20. **Laboratory-Scale Extraction from Secondary Sources** – Analytical isolation and purification of iridium.
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✅ **Summary:**
* **Main industrial sources:** Platinum group ores, nickel-copper sulfide ores.
* **Primary extraction steps:** Ore concentration → smelting → acid digestion → formation of iridium chlorides → reduction to metallic iridium.
* **Metallic iridium:** Produced via reduction of IrCl₃, IrCl₄, or (NH₄)₂\[IrCl₆].
* **Byproduct/secondary sources:** Platinum refinery residues, PGM scrap catalysts, smelting slags.
* **Laboratory/experimental:** Ion exchange, solvent extraction, selective precipitation, calcination, and reduction cycles.
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Next in periodic order is \*\*Platinum (Pt, atomic number 78). Do you want me to continue with **20 extraction methods for Platinum**?