Information: Calcium
Known Methods of Extraction
Perfect 👍 — next in **periodic table order** is **Calcium (Ca, atomic number 20).** Calcium is highly reactive and **never occurs free in nature**. It is abundant in **limestone (CaCO₃), gypsum (CaSO₄·2H₂O), fluorite (CaF₂), and dolomite (CaMg(CO₃)₂)**. Extraction methods produce **metallic calcium** or calcium compounds. Here are the **20 most common methods of extracting Calcium**: --- # **20 Most Common Methods of Extracting Calcium** ### **A. Industrial / Large-Scale Thermal Methods** 1. **Electrolysis of Molten Calcium Chloride (CaCl₂)** – Main modern method for metallic calcium. 2. **Downs Cell Electrolysis of CaCl₂** – Variant similar to the sodium Downs cell. 3. **Thermal Reduction of CaO with Aluminum (Aluminothermic)** – Produces calcium metal. 4. **Reduction of CaO with Magnesium (Magnesiothermic)** – Laboratory/industrial method. 5. **Reduction of CaCO₃ with Aluminum at High Temperatures** – Produces Ca metal + CO gas. 6. **Reduction of CaO with Silicon** – Research/experimental method. --- ### **B. Chemical / Laboratory Methods** 7. **Reduction of CaCl₂ with Sodium** – Laboratory method, displacement reaction. 8. **Reduction of Calcium Salts (CaF₂, CaCO₃) with Magnesium** – Lab-scale. 9. **Reduction of CaO with Calcium Hydride** – Experimental displacement method. 10. **Calciothermic Reduction of Calcium Oxide with Aluminum Alloys** – Research method. 11. **Electrolysis of Aqueous CaCl₂ (with Inert Electrodes, Lab Only)** – Produces small amounts of Ca. 12. **Vacuum Thermal Reduction of CaO** – Produces calcium vapor, condensed to metal. --- ### **C. Extraction of Calcium Compounds** 13. **Calcination of Limestone (CaCO₃ → CaO + CO₂)** – Produces quicklime, precursor for metallic calcium or Ca-based chemicals. 14. **Production of Calcium Hydroxide (Ca(OH)₂) from CaO + Water** – Common chemical form. 15. **Extraction of Calcium Sulfate (CaSO₄) from Gypsum** – Thermal dehydration yields CaO. 16. **Extraction of Calcium Fluoride (CaF₂) from Fluorite** – Thermal treatment yields CaO or Ca metal in lab. --- ### **D. Specialized / Experimental Methods** 17. **Electrochemical Reduction of Ca²⁺ in Molten Salts** – Lab-scale method. 18. **Plasma-Assisted Calcium Production from CaO** – Research method. 19. **Solar Thermal Reduction of CaCO₃** – Concentrated sunlight drives reduction to CaO, CO₂, and potentially Ca metal. 20. **High-Temperature Carbothermic Reduction of Ca Compounds** – Experimental lab method. --- ✅ **Summary:** * **Main industrial method:** Electrolysis of molten CaCl₂ to produce metallic calcium. * **Historic / lab methods:** Reduction of CaO or CaCl₂ with aluminum, magnesium, or sodium. * **Calcium compounds:** CaO, Ca(OH)₂, CaF₂, and CaSO₄ are extracted via calcination or chemical conversion. * **Natural occurrence:** Always in compounds; never free due to high reactivity. --- Next in periodic order is **Scandium (Sc, atomic number 21).** Do you want me to continue with **20 extraction methods for Scandium**?