Metallurgy — Extraction Methods
Metallurgy
35
JEE Qs
0%
Hard
100
min
Master the principles behind each extraction method and memorize key examples, specific reagents, and important reactions, paying special attention to Ellingham diagrams for thermodynamic feasibility.
🧮 Key Formulas
✅ Key Points for JEE
- 1Concentration methods (Hydraulic washing, Froth flotation, Magnetic separation, Leaching) are chosen based on the specific physical or chemical properties of the ore and gangue.
- 2Ellingham Diagram is a graphical representation of ΔG° vs T for the formation of metal oxides; it helps predict the thermodynamic feasibility and ideal temperature range for reduction of metal oxides by various reducing agents.
- 3A metal can reduce the oxide of another metal if its ΔG° line lies below that of the metal oxide to be reduced at the given temperature.
- 4Reducing agents vary based on the metal's reactivity: carbon/CO for moderately reactive metals (Fe, Zn), H₂ for less reactive metals (W, Mo), self-reduction for very less reactive metals (Cu, Pb), and electrolysis for highly reactive metals (Al, Na, Mg).
- 5Leaching involves treating the powdered ore with a suitable chemical reagent to convert the metal into a soluble complex, while impurities remain insoluble.
⚠️ Common Mistakes
- ✕Misinterpreting Ellingham diagrams, especially when comparing reducing powers or identifying the crossover points as suitable reduction temperatures.
- ✕Confusing the appropriate reducing agent (C, CO, H₂, or self-reduction) for different metal oxides based on their stability and temperature requirements.
- ✕Not knowing specific examples of ores and the exact reagents or conditions used for each concentration and extraction method (e.g., NaCN for gold leaching, depressants in froth flotation).
- ✕Ignoring the role of flux in smelting, which forms slag by combining with gangue, or confusing calcination and roasting conditions.
📝 Practice Questions
See allQ49.Which of the following metals can be extracted through alkali leaching technique? (1) Sn (2) Pb (3) Au (4) Cu JEE Main 2023 (08 Apr Shift 1) JEE Main Previous Year Paper
Q41.Which of the following is used as a stabilizer during the concentration of sulphide ores? (1) Pine oils (2) Fatty acids (3) Xanthates (4) Cresols
Q39.Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason 𝑅 Assertion A: In an Ellingham diagram, the oxidation of carbon to carbon monoxide shows a negative slope with respect to temperature. Reason R: CO tends to get decomposed at higher temperature. In the light of the above statements, choose the correct answer from the options given below (1) Both A and R are correct and R is the correct (2) A is not correct but R is correct explanation of A (3) (3) Both A and R are correct but R is NOT the (4) A is correct but R is not correct correct explanation of A
Q51.Among following compounds, the number of those present in copper matte is A. CuCO3 B. Cu2 S C. Cu2 O D. FeO
Q51.In Hall-Heroult process, the following is used for reducing Al2 O3 :- (1) Magnesium (2) Na3 AlF6 (3) Graphite (4) CaF2
Q41.In the extraction process of copper, the product obtained after carrying out the reactions (i) 2Cu2 S + 3O2 ⟶2Cu2O + 2SO2 (ii) 2Cu2O + Cu2 S ⟶6Cu + SO2 is called (1) Blister copper (2) Reduced copper (3) Copper scrap (4) Copper matte
NCERT Chapters
- Class 12 Chemistry Part I Ch 6: General Principles and Processes of Isolation of Elements