Sphalerite is concentrated by

Options

A. gravity separation
B. froth floatation
C. magnetic separation
D. hydraulic washing

Explanation

### Step-by-Step Solution:

1. **Understanding Sphalerite**:
- Sphalerite is a mineral composed primarily of zinc sulfide (ZnS). It is the main ore of zinc and is often found in association with other minerals.

2. **Identifying Concentration Methods**:
- The question asks about the method used to concentrate sphalerite. The options provided are:
- A. Gravity separation
- B. Froth flotation
- C. Magnetic separation
- D. Hydraulic washing

3. **Analyzing the Methods**:
- **Gravity Separation**: This method is used for ores that have a significant difference in density between the ore and the gangue. It is not typically effective for sulfide ores like sphalerite.
- **Froth Flotation**: This is a widely used method for concentrating sulfide ores. It works by creating a froth that selectively separates hydrophobic (non-wettable) mineral particles from hydrophilic (wettable) gangue particles.
- **Magnetic Separation**: This method is effective for magnetic ores, and sphalerite is not magnetic.
- **Hydraulic Washing**: This method uses water to separate particles based on their size and density, but it is not as effective for fine sulfide ores.

4. **Conclusion**:
- The most suitable method for concentrating sphalerite is **Froth Flotation**. This method is specifically designed for sulfide ores and effectively separates zinc sulfide from gangue materials.

### Final Answer:
Sphalerite is concentrated by **Froth Flotation**.

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