Question

Which of the following ore is concentrated by Froth floatation process?

• A. \(ZnCO_3\)
• B. \(ZnO\)
• C. \(ZnS\)
• D. \(Na_2S\)

Hint:

Associate the froth floatation process directly with Sulfide Ores (suffix "-S" like \(ZnS\), \(PbS\), \(CuFeS_2\)).
Sulfide minerals preferentially wet with oil, while gangue wets with water.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to identify which of the given ores is concentrated using the industrial froth floatation metallurgical process.

Step 2: Key Formula or Approach:
The froth floatation process is specifically used for the concentration of sulfide ores based on the difference in the wetting properties of the ore particles and the gangue impurities with water and oils.

Step 3: Detailed Explanation:

• The froth floatation process utilizes a suspension of the powdered ore in water.

• Collectors (like pine oil or xanthates) are added to wet the sulfide ore particles, making them hydrophobic (water-repelling).

• When air is blown through the suspension, the hydrophobic sulfide ore particles attach to the rising air bubbles and form a stable froth at the surface, which is skimmed off.

• The gangue particles (earthy impurities) are hydrophilic (water-attracting) and remain settled at the bottom of the tank.

• Let us analyze the options:
- (A) \(ZnCO_3\) (Calamine): A carbonate ore of zinc, concentrated by gravity separation/calcination.
- (B) \(ZnO\) (Zincite): An oxide ore of zinc.
- (C) \(ZnS\) (Zinc blende): A sulfide ore of zinc. Since it is a sulfide ore, it is concentrated using the froth floatation process.
- (D) \(Na_2S\): Sodium sulfide, which is a highly soluble salt, not an insoluble mineral ore.

• Therefore, \(ZnS\) is concentrated by the froth floatation process.


Step 4: Final Answer:
The ore concentrated by froth floatation is \(ZnS\), matching Option (C).