Question

Which of the following acts as ‘activator’ in froth flotation process?

• A. KCN
• B. NaCN
• C. Sodium ethyl xanthate
• D. Copper sulphate

Hint:

Xanthates = collectors/activators; cyanides = depressants.

Answer 1

The Correct Option is C

Step 1: In froth flotation, an activator is the reagent that selectively makes ore particles hydrophobic.
Step 2: Xanthates form surface complexes with sulphide ores: \[ \text{Ore} + \text{xanthate} \rightarrow \text{hydrophobic layer}. \]
Step 3: Cyanides (KCN/NaCN) are depressants, not activators. Copper sulphate activates ZnS only in special cases, not general activator.
Step 4: The standard universal activator = sodium ethyl xanthate. Hence → (C).