Answer: Chemisorbs on sulfide surfaces via dithioate (CSS-) group coordination to Cu/Fe/Zn ions, making the surface strongly hydrophobic.
- A Chemisorbs on sulfide surfaces via dithioate (CSS-) group coordination to Cu/Fe/Zn ions, making the surface strongly hydrophobic
- B Generally dissolves largely into the surrounding water without ever binding to any mineral surface according to conventional understanding
- C Acts as a chemical reducing agent that directly converts the metal sulfide into the free elemental metal in routine practice
- D Functions mainly as a surfactant whose sole job is to stabilise the rising froth bubbles overall in most cases under typical conditions
Correct answer: A. Chemisorbs on sulfide surfaces via dithioate (CSS-) group coordination to Cu/Fe/Zn ions, making the surface strongly hydrophobic
Explanation: Xanthate (RO-CS2-) binds strongly to metal sulfide surfaces via dative bonding of the sulfur atoms to surface metal ions, making the sulfide particles hydrophobic 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.