Perfect 👍 — next is **Argon (Ar, atomic number 18).**
Argon is a **noble gas**, chemically inert, and occurs in the **Earth’s atmosphere at \~0.93% by volume**. Like neon, it’s extracted **physically** via **air separation techniques**, not chemical reactions.
Here are the **20 most common methods of extracting Argon**:
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# **20 Most Common Methods of Extracting Argon**
### **A. Industrial Air Separation (Primary Source)**
1. **Cryogenic Fractional Distillation of Liquid Air** – Main industrial method; argon separated from N₂/O₂ based on boiling points.
2. **Double Fractional Distillation Columns** – First separate O₂/N₂, then isolate argon from the nitrogen-rich fraction.
3. **Rectification in Low-Temperature Columns** – Specialized columns for high-purity argon production.
4. **Argon Recovery from Liquid Oxygen Storage Tanks** – Skim argon-rich gas during oxygen production.
5. **Integrated Argon Recovery Units in Air Separation Plants** – Captures argon as a byproduct of oxygen/nitrogen production.
6. **Air Separation with Heat Exchangers** – Optimized cooling cycles improve argon yield.
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### **B. Alternative Air Separation Approaches**
7. **Pressure Swing Adsorption (PSA) Pre-Concentration** – Enriches argon fraction before cryogenic separation.
8. **Vacuum Swing Adsorption (VSA)** – Uses vacuum cycles to pre-concentrate argon.
9. **Membrane Separation (Pre-Enrichment)** – Experimental; membranes slightly enrich argon.
10. **Helium-Argon Co-Separation** – Argon often appears with helium in natural gas; separation needed.
11. **Zeolite Adsorption at Cryogenic Temperatures** – Adsorbs N₂/O₂, leaving argon-enriched gas.
12. **Activated Carbon Adsorption** – Laboratory or small-scale pre-concentration.
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### **C. Byproduct Recovery**
13. **Recovery from Liquid Nitrogen Production Streams** – Argon is extracted from N₂-rich streams.
14. **Recovery from Oxygen Liquefaction for Steelmaking** – Industrial O₂ plants produce argon as a side-product.
15. **Collection from Natural Gas (He-Ar Mixtures)** – Some natural gases contain trace argon, separated cryogenically.
16. **Side-Draws in Large-Scale LNG Plants** – Rare, but argon can be concentrated in natural gas processing.
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### **D. Laboratory & Experimental Techniques**
17. **Fractional Evaporation of Cryogenic Air Mixtures** – Lab-scale argon enrichment.
18. **Low-Temperature Gas Chromatography** – Separates noble gases, including argon.
19. **Getter-Freezing / Cold Traps** – Argon remains uncondensed while other gases freeze out.
20. **Mass Spectrometry or Isotope Separation** – Ultra-trace argon isotope extraction for research.
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✅ **Summary:**
* **Main industrial process:** Cryogenic fractional distillation of air.
* **Secondary methods:** Byproduct recovery from oxygen plants, natural gas, or helium-rich streams.
* **Lab/research methods:** Low-temperature gas chromatography, cold traps, PSA/VSA pre-concentration.
* **Natural occurrence:** \~0.93% of air; inert and chemically unreactive.
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Next in periodic order is **Potassium (K, atomic number 19).**
Shall I continue with **20 extraction methods for Potassium**?
