Which one of the following ores is best concentrated by froth flotation method:

Options

A. cassiterite
B. Galena
C. Malachite
D. Magnetite

Answer

To determine which ore is best concentrated by the froth flotation method, we need to analyze the given options and understand the principles of the froth flotation process.

### Step-by-Step Solution:

1. **Understanding Froth Flotation**:
- Froth flotation is a method used to separate hydrophobic materials from hydrophilic ones. It is particularly effective for concentrating sulfide ores.
- The process involves mixing the ore with water and a frothing agent (like pine oil) in a vessel where air is introduced, creating bubbles. The hydrophobic particles attach to the bubbles and rise to the surface, forming a froth that can be skimmed off.

2. **Identifying the Ores**:
- The ores provided are:
- Cassiterite (SnO2)
- Galena (PbS)
- Malachite (CuCO3·Cu(OH)2)
- Magnetite (Fe3O4)

3. **Analyzing Each Ore**:
- **Cassiterite (SnO2)**: This is a tin oxide and is not a sulfide ore. It is typically concentrated by gravity separation methods.
- **Galena (PbS)**: This is a lead sulfide and is a typical example of a sulfide ore. It is well-suited for concentration by froth flotation.
- **Malachite (CuCO3·Cu(OH)2)**: This is a copper carbonate and is not a sulfide ore. It is usually concentrated by leaching methods.
- **Magnetite (Fe3O4)**: This is an iron oxide and is not a sulfide ore. It is generally concentrated using magnetic separation.

4. **Conclusion**:
- Among the given options, **Galena (PbS)** is the only sulfide ore, making it the best candidate for concentration using the froth flotation method.

### Final Answer:
**Galena (PbS)** is the ore that is best concentrated by the froth flotation method.

---