Answer: Sulfide ores (e.g., ZnS, PbS, Cu2S) using pine oil.
- A Sulfide ores (e.g., ZnS, PbS, Cu2S) using pine oil
- B Oxide ores, which are instead concentrated by magnetic separation
- C Carbonate ores, which are instead concentrated by gravity separation
- D Native metals, which require no concentration step at all
Correct answer: A. Sulfide ores (e.g., ZnS, PbS, Cu2S) using pine oil
Explanation: Froth flotation: crushed ore in water with pine oil (collector) and pine oil generates froth; sulfide mineral particles are hydrophobic and float; gangue sinks.
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.