During the concentration of Zinc Blende () via froth flotation, its natural floating characteristic — Metallurgy and Isolation of Elements Chemistry Question
Question
During the concentration of Zinc Blende ($ZnS$) via froth flotation, its natural floating characteristic is remarkably poor compared to other sulphides. To rectify this, an "Activator" is added to the tank. Which chemical acts as the activator, and what is the surface reaction mechanism?
💡 Solution & Explanation
Zinc blende ($ZnS$) floats poorly. Copper sulphate ($CuSO_4$) is added as an activator. It undergoes a surface displacement reaction: $ZnS + CuSO_4 \rightarrow CuS + ZnSO_4$. The $ZnS$ particles become coated in a thin film of Copper(II) sulphide ($CuS$), which is highly hydrophobic and floats exceptionally well.