Answer: Make the ore surface hydrophobic so it attaches to air bubbles.
- A Make the ore surface hydrophobic so it attaches to air bubbles
- B Chemically dissolve the ore particles into the surrounding water
- C React directly with the gangue to convert it into soluble salts
- D Generate the stable froth layer at the top of the flotation cell
Correct answer: A. Make the ore surface hydrophobic so it attaches to air bubbles
Explanation: Collectors (e.g., xanthates, thio compounds) adsorb on the metal sulfide surface, making it hydrophobic, allowing it to attach to air bubbles and float.
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.