Which of the following method is not used for the concentration of bauxite ore

Options

A. Froth flotation
B. Electromagnetic separation
C. Chemical separation
D. Hydraulic separation

Answer

To determine which methods are not used for the concentration of bauxite ore, we need to analyze each method provided in the question.

### Step 1: Understand Bauxite Ore
Bauxite ore is primarily composed of aluminum oxide (Al2O3) and water (H2O). It is the main source of aluminum.

**Hint:** Remember that bauxite is primarily aluminum oxide, which will help in identifying the appropriate concentration methods.

### Step 2: Analyze Froth Flotation
Froth flotation is a method commonly used for the concentration of sulfide ores. Since bauxite does not contain sulfur, froth flotation is not suitable for concentrating bauxite ore.

**Hint:** Froth flotation is effective for sulfide ores; think about the composition of bauxite to see if it fits.

### Step 3: Analyze Electromagnetic Separation
Electromagnetic separation is a technique used to separate metals from their ores based on their magnetic properties. However, this method is not typically used for bauxite ore concentration, as it does not effectively separate aluminum oxide.

**Hint:** Consider the properties of aluminum oxide and whether they can be separated magnetically.

### Step 4: Analyze Chemical Separation
Chemical separation involves using reagents to dissolve the ore and remove impurities. This method is applicable for bauxite ore, as it helps to concentrate the aluminum oxide by removing impurities.

**Hint:** Chemical separation focuses on dissolving the ore, which is relevant for bauxite.

### Step 5: Analyze Hydraulic Separation
Hydraulic separation is used for the concentration of oxide and carbonate ores. Since bauxite is an oxide ore (aluminum oxide), this method can be used for its concentration.

**Hint:** Hydraulic separation is suitable for oxides; relate this to the composition of bauxite.

### Conclusion
Based on the analysis:
- Froth flotation and electromagnetic separation are not used for the concentration of bauxite ore.
- Chemical separation and hydraulic separation are methods that can be used for concentrating bauxite ore.

**Final Answer:** The methods not used for the concentration of bauxite ore are Froth flotation and Electromagnetic separation.