Question

The froth flotation method is mainly used for

• A. oxide ores
• B. carbonate ores
• C. sulphide ores
• D. silicate ores

Hint:

Xanthates are the most common collectors used for sulfide flotation, while frothers like pine oil or methyl isobutyl carbinol (MIBC) are added to stabilize the bubbles at the top of the cell.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify the mineral ore class for which froth flotation is most commonly utilized as a separation process in mineral dressing.

Step 2: Key Formula or Approach:
Froth flotation relies on the differences in surface hydrophobic (water-repelling) and hydrophilic (water-attracting) properties of minerals.
Sulfide minerals are naturally or chemically made hydrophobic by adding specific collectors (like xanthates), allowing them to selectively attach to air bubbles and rise to the surface.

Step 3: Detailed Explanation:

• Sulfide Mineral Flotation: Sulfide minerals (such as chalcopyrite \( \text{CuFeS}_2 \), galena PbS, and sphalerite ZnS) have crystalline surfaces that readily adsorb sulfhydryl collectors (like potassium ethyl xanthate).
The collector molecules orient their non-polar, hydrophobic hydrocarbon tails outward, rendering the sulfide mineral particles highly hydrophobic.
When air is bubbled through the agitated slurry, these hydrophobic particles attach to the rising bubbles, forming a stable froth layer at the top of the cell that is skimmed off as concentrate.

• Analysis of Other Options:
-

Oxide, carbonate, and silicate ores (Options A, B, and D) are highly polar and hydrophilic. They do not easily interact with simple thiol collectors, making them more difficult to float without complex, expensive chemical conditioning.
- They are more commonly separated using gravity concentration, magnetic separation, or hydrometallurgical leaching processes.


Step 4: Final Answer:
Thus, the froth flotation method is mainly used for sulphide ores, corresponding to Option (C).