Refining of Metals

📚 Key Concepts

🔹 Real-Life Example

Even after extraction, metals contain impurities – like getting 90% pure gold but needing 99.9% for electronics. Just as you might filter coffee to remove grounds, metals need “filtering” to remove impurities. Different methods work for different metals – distillation for zinc, electrolysis for copper.

🧪 Refining Methods

🔸 Electrolytic Refining

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Most important method for metals like copper

Setup:

  • Anode: Impure metal
  • Cathode: Pure metal strip
  • Electrolyte: Salt solution of the metal

Process:

  • At Anode: Cu → Cu²⁺ + 2e⁻ (impure copper dissolves)
  • At Cathode: Cu²⁺ + 2e⁻ → Cu (pure copper deposits)
  • Anode mud: Contains valuable metals (Ag, Au, Pt)

🔸 Other Methods

  1. Distillation: For low-boiling metals (Zn, Hg)
  2. Liquation: For low-melting metals (tin)
  3. Poling: Using wooden poles to stir molten metal