Definition of Ore:

• Ores are naturally occurring rocks or minerals containing sufficient quantities of metal for economic extraction.

Stages in Metal Extraction:

• Concentration of Ore: Removal of impurities (gangue) to increase the metal concentration.
  • Methods include:
    • Froth Flotation: For sulfide ores like copper.
    • Magnetic Separation: For ores like hematite (iron).
    • Gravity Separation: For denser ore particles.

• Extraction of Metal:
  • Metals are extracted depending on their position in the reactivity series.
• Purification of Metal: Removing impurities to obtain pure metal.

Classification Based on Reactivity:

• Highly Reactive Metals:
  • Extracted via Electrolysis.
  • Example: Aluminium from bauxite (Al₂O₃·2H₂O).

• Moderately Reactive Metals:
  • Reduced using carbon or carbon monoxide.
  • Example: Iron from hematite (Fe₂O₃) using a blast furnace.

• Less Reactive Metals:
  • Found in the free state or reduced by simple methods.
  • Example: Gold, silver.

Common Methods of Extraction:

• Reduction by Carbon:
  • Used for metals like iron.
  • Reaction: Fe₂O₃ + 3CO → 2Fe + 3CO₂.
• Electrolytic Reduction:
  • Used for metals like sodium, potassium, and aluminium.
  • Reaction: 2Al₂O₃ → 4Al + 3O₂ (in a molten state).
• Thermal Decomposition:
  • For less stable ores.
  • Example: 2HgO → 2Hg + O₂.

Blast Furnace Process for Iron:

• Inputs: Iron ore, coke, and limestone.
• Outputs: Molten iron and slag (waste material).
• Reaction:
  • Formation of CO: C + O₂ → CO₂; CO₂ + C → 2CO.
  • Reduction of iron ore: Fe₂O₃ + 3CO → 2Fe + 3CO₂.

Purification of Metals:

• Impure metals are purified using Electrolytic Refining.
  • Example: Copper refining.
  • Impure copper is the anode; pure copper collects at the cathode.

Environmental Considerations:

• Mining and extraction lead to habitat destruction, pollution, and energy use.
• Recycling and sustainable methods can minimize environmental impact.