An ore of tin containing ` FeCrO_4 ` is concentrated by …………. .

Answer

To concentrate an ore of tin that contains FeCrO4, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components**: The ore contains tin and FeCrO4 (chromite), where FeCrO4 is an impurity in the context of tin extraction.

2. **Understand the Properties**: Recognize that FeCrO4 has magnetic properties due to the presence of iron, which has unpaired electrons. In contrast, tin does not exhibit magnetic properties.

3. **Choose the Concentration Method**: Since FeCrO4 is magnetic and tin is not, we can use magnetic separation to concentrate the ore. This method takes advantage of the difference in magnetic properties between the two substances.

4. **Perform Magnetic Separation**:
- Pass the crushed ore through a magnetic separator.
- The magnetic particles (FeCrO4) will be attracted to the magnet and removed from the mixture.
- The non-magnetic particles (tin) will remain behind.

5. **Collect the Concentrated Ore**: After the magnetic separation, the remaining material will be enriched in tin, effectively concentrating the ore by removing the FeCrO4 impurity.

### Final Answer:
An ore of tin containing FeCrO4 is concentrated by **magnetic separation**.

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