Answer: Green wood poles stirred in molten blister copper to reduce Cu 2 O to Cu using hydrocarbons.
- A Green wood poles stirred in molten blister copper to reduce Cu<sub>2</sub>O to Cu using hydrocarbons
- B An electrolytic cell with a pure copper cathode and impure copper anode in most cases
- C Solid coke added directly to the molten copper bath under typical conditions according to standard textbooks
- D Zone refining by passing a molten zone along a copper bar in general practice as frequently described
Correct answer: A. Green wood poles stirred in molten blister copper to reduce Cu<sub>2</sub>O to Cu using hydrocarbons
Explanation: Poling: green wood introduces hydrocarbons that reduce Cu<sub>2</sub>O (from over-oxidation): Cu<sub>2</sub>O + C → 2Cu + CO.
An Ellingham diagram plots ΔG° of oxide formation against temperature for different metals; whichever line is LOWER (more negative ΔG°) at a given temperature reduces the oxide of any metal whose line sits above it - the basis of carbon reduction (Fe, Zn) vs electrolytic reduction (Al, Mg, Na) decisions.
Concept context
The science of extracting metals from ores and refining them for use. Covers concentration methods, reduction techniques, refining processes, and the thermodynamic principles that govern metal extraction.