Which of the following sulphide ore is not concentrated by froth-floatation process ?

Options

A. Galena
B. Zinc blend
C. Argentite
D. Cinnabar

Answer

To determine which of the following sulphide ores is not concentrated by the froth-flotation process, we need to analyze each option based on the principles of the froth-flotation method.

### Step-by-Step Solution:

1. **Understand the Froth-Flotation Process**:
- The froth-flotation process is a method used for separating minerals from gangue based on differences in their hydrophobicity.
- In this process, sulphide ores are preferentially wetted by a collector (like pine oil), while the gangue particles are wetted by water.

2. **Identify the Given Ores**:
- The options provided are:
- A) Galena (PbS)
- B) Zinc Blend (ZnS)
- C) Argentite (Ag2S)
- D) Cinnabar (HgS)

3. **Analyze Each Ore**:
- **Galena (PbS)**: This is a common sulphide ore of lead and is effectively concentrated by froth-flotation.
- **Zinc Blend (ZnS)**: This is the principal ore of zinc and can also be concentrated using the froth-flotation method.
- **Argentite (Ag2S)**: This is a silver sulphide ore, but it is not typically concentrated by froth-flotation due to its different properties.
- **Cinnabar (HgS)**: This is the primary ore of mercury and can be concentrated using froth-flotation.

4. **Conclusion**:
- Among the given options, **Argentite (Ag2S)** is the sulphide ore that is not concentrated by the froth-flotation process. Therefore, the correct answer is **Option C: Argentite**.

### Final Answer:
**Option C: Argentite (Ag2S)** is not concentrated by the froth-flotation process.

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