Observation

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Extractive metallurgy is the branch of metallurgy concerned with the production   
of metals from their ores. The branches of extractive metallurgy are pyrometallurgy, hydrometallurgy and electrometallurgy.

Pyrometallurgy

• Involves thermal treatment
• Thermal treatment leads to purification of ores or alloys
• The process involves high degree of heat
• The source of heat is either fossil fuels or electricity
• Could involve roasting
• Involves smelting
• Involves refining
• Metals that could be produced using pyrometallurgy include iron, zinc chromium, tin etc.
• Carried out in furnaces

Hydrometallurgy

• Involves the use of aqueous solution
• Chemical reaction leads to dissolution of ores or alloys
• Could involve use of other solvents apart from water
• Metals are recovered from solutions
• Could involve leaching
• Involves pollution purification
• Involves metal recovery
• Metals that could be extracted through hydrometallurgy include copper, gold,  zinc etc

Electrometallurgy

• Involves use of aqueous solutions
• Could involve use of other solvents
• The metallic solution is fed into electrolytic cell
• Electric current is applied
• The ionized metals are separated from other impurities
• It includes electro-refining
• Metals that could be separated using this method include gold, silver, zinc, aluminium, cobalt etc