Great 👍 — next in **periodic table order** is **Chromium (Cr, atomic number 24).**
Chromium is a **transition metal** that does not occur free in nature. It is mainly found in **chromite ore (FeCr₂O₄)**. Industrial extraction focuses on producing **ferrochromium** or **metallic chromium** via **reduction of chromite**.
Here are the **20 most common methods of extracting Chromium**:
---
# **20 Most Common Methods of Extracting Chromium**
### **A. Industrial / Large-Scale Extraction**
1. **Aluminothermic Reduction of Chromite Ore (FeCr₂O₄ + Al → Cr + Fe + Al₂O₃)** – Produces metallic chromium in small batches.
2. **Carbothermic Reduction in Electric Arc Furnace (Chromite + Coke → Ferrochromium)** – Main industrial method.
3. **Smelting of Chromite Ore with Silica Flux** – Produces ferrochromium alloy.
4. **Reduction of Cr₂O₃ with Aluminum** – Lab-scale production of pure Cr metal.
5. **Reduction of Cr₂O₃ with Calcium (Calciothermic)** – Experimental or specialty lab method.
6. **Electrolytic Reduction of Cr₂O₃ in Molten Salts** – Produces high-purity metallic chromium.
---
### **B. Extraction from Ferroalloys / Slags**
7. **Chromite Roasting with Alkali (Na₂CO₃) → Soluble Sodium Chromate** – Converts Cr(III) → Cr(VI) for chemical use.
8. **Leaching of Sodium Chromate with Water or Acid** – Produces chromate solutions.
9. **Reduction of Chromates (Na₂CrO₄ → Cr₂O₃ → Cr metal)** – For chemical or metallic chromium.
10. **Ferrochromium Production via Submerged Arc Furnace** – Smelting process producing Cr-Fe alloy.
11. **Extraction from Ferrochromium Slags** – Reprocessing residual Cr₂O₃ in slags.
12. **Electrolytic Refining of Ferrochromium** – Lab-scale purity improvement.
---
### **C. Laboratory / Small-Scale Methods**
13. **Reduction of CrCl₃ with Alkali Metals (Na/K)** – Produces metallic Cr powder.
14. **Reduction of Cr₂O₃ with Magnesium** – Lab-scale metallothermic method.
15. **Reduction of Chromate Salts with Hydrogen** – Produces Cr metal or Cr₂O₃ powder.
16. **Carbothermic Reduction of Cr₂O₃ at High Temp** – Experimental lab method.
---
### **D. Specialized / Novel Methods**
17. **Electrochemical Reduction of Cr³⁺ in Molten Salts** – Produces high-purity Cr.
18. **Plasma Reduction of Cr₂O₃** – Produces pure chromium powder.
19. **Recovery of Chromium from Industrial Waste / Slags** – Secondary source extraction.
20. **Solar-Thermal Carbothermic Reduction of Chromite** – Experimental high-temp solar process.
---
✅ **Summary:**
* **Main industrial method:** Smelting of chromite ore in **electric arc furnaces** to produce **ferrochromium**.
* **Metallic chromium production:** Aluminothermic or calciothermic reduction, or electrolytic reduction of Cr₂O₃.
* **Chemical chromium compounds:** Roasting with alkali → chromates → Cr₂O₃.
* **Laboratory/experimental:** Mg/Al reduction, plasma, electrochemical, and solar thermal methods.
---
Next in periodic order is **Manganese (Mn, atomic number 25).**
Do you want me to continue with **20 extraction methods for Manganese**?
