Which one of the following is not a method of concentrain of ore?

Options

A. Electromagnetic separation
B. Smelting
C. Gravity separation
D. Froth floatation process

Answer

To determine which of the following is not a method of concentration of ore, we need to analyze the given options: electromagnetic separation, smelting, gravity separation, and froth flotation process.

### Step-by-Step Solution:

1. **Understanding Ore Concentration**:
- Ore concentration is the process of removing unwanted materials from the ore, which enhances the quality of the ore for further processing.

2. **Identifying Methods of Concentration**:
- **Electromagnetic Separation**: This method separates materials based on their magnetic properties. It is effective for separating metallic impurities from non-magnetic materials.
- **Gravity Separation**: This technique separates components based on their specific weights. Heavier particles settle at the bottom while lighter ones remain on top.
- **Froth Flotation Process**: This method separates materials based on their hydrophobic (water-repellent) and hydrophilic (water-attracting) properties. It is commonly used for sulfide ores.

3. **Analyzing the Remaining Option**:
- **Smelting**: This is a process that involves heating the ore to extract the base metal. It is not a method of concentration but rather a method of extraction.

4. **Conclusion**:
- Among the options provided, smelting is not a method of concentration of ore. Therefore, the answer is **smelting**.

### Final Answer:
**Smelting is not a method of concentration of ore.**