Principles of Metallurgy — Telangana (SSC) Class 10 Science Solutions (Free)
Free step-by-step Telangana (SSC) Class 10 Science solutions for "Principles of Metallurgy" — important questions with detailed answers, download PDF for board exam preparation.
TL;DR: Free step-by-step Telangana (SSC) Class 10 Science solutions for "Principles of Metallurgy" — important questions with detailed answers, download PDF…
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Q1: Define ore and give 3 examples with their chemical formulas. Explain concentration of ore.
Ore: A naturally occurring mineral deposit from which a metal can be extracted economically.
Examples:
1. Bauxite (Al₂O₃·2H₂O) - ore of aluminum
2. Hematite (Fe₂O₃) - ore of iron
3. Chalcopyrite (CuFeS₂) - ore of copper
Concentration of ore: Process of removing unwanted impurities (gangue) from ore to increase metal content.
Methods:
1. Gravity separation (different densities)
2. Magnetic separation (magnetic property difference)
3. Froth flotation (wetting properties difference)
Q2: Explain the difference between roasting and calcination with suitable examples.
Roasting:
• Ore heated strongly in presence of air/oxygen
• Converts ore to oxide
• Example: 2ZnS + 3O₂ → 2ZnO + 2SO₂
• Used for sulfide ores (galena, chalcopyrite, sphalerite)
Calcination:
• Ore heated strongly in absence of air/limited oxygen
• Decomposes ore by heat
• Example: CaCO₃ → CaO + CO₂
• Used for carbonate ores (limestone, dolomite) and hydroxide ores (bauxite)
Key difference: Roasting requires oxygen; calcination requires absence of oxygen
Q3: Describe the extraction of iron from hematite ore using blast furnace. Name the three zones.
Blast Furnace has three zones:
1. Combustion Zone (bottom, 1500°C): Coke burns in air → C + O₂ → CO₂ + heat
2. Reduction Zone (middle, 800-1200°C): Iron oxide reduced → Fe₂O₃ + 3CO → 2Fe + 3CO₂
3. Fusion Zone (upper): Limestone (CaCO₃) decomposes → CaO + CO₂. CaO combines with impurities (silica) → slag (CaSiO₃) separates from molten iron
Output: Molten iron (pig iron) at bottom; slag floats on top
Overall: Fe₂O₃ + 3CO → 2Fe + 3CO₂
Q4: What is the reactivity series? Explain how it helps in metal extraction.
Reactivity series: An arrangement of metals in decreasing order of their reactivity (tendency to lose electrons).
Order (most to least reactive): K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > Cu > Hg > Ag > Au
Application in metal extraction:
1. Highly reactive metals (K, Na): Extracted by electrolysis of molten compounds
2. Moderately reactive metals (Al, Mg, Zn): Extracted by electrolysis or carbon reduction
3. Less reactive metals (Fe, Cu): Extracte…
Q5: Explain the process of refining crude iron into steel. What are the main impurities removed?
Refining crude iron (pig iron) into steel:
Process (Bessemer or Open Hearth method):
Step 1: Molten pig iron heated in furnace
Step 2: Air blown through molten iron → oxygen reacts with impurities
Step 3: Carbon oxidized: C + O₂ → CO₂ (removes excess carbon)
Step 4: Phosphorus oxidized: 4P + 5O₂ → 2P₂O₅
Step 5: Silicon oxidized: Si + O₂ → SiO₂
Step 6: Lime (CaO) added → forms slag with oxides
Step 7: Slag removed; refined steel remains
Main impurities removed: Carbon, phosphorus, silicon, sulf…
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