A sulphide ore is converted into metal oxide by the process of:

Options

A. Calcination
B. Roasting
C. Smelting
D. Leaching

Answer

To solve the question regarding the conversion of a sulphide ore into metal oxide, we will analyze the options provided and determine the correct process.

### Step-by-Step Solution:

1. **Understanding the Processes**:
- **Calcination**: This process involves heating an ore in the absence or limited supply of oxygen. It is primarily used for carbonate ores, where the ore is converted to an oxide and carbon dioxide is released.
- **Roasting**: This process involves heating a sulphide ore in the presence of excess oxygen. During roasting, the sulphide is converted into an oxide, along with the release of sulphur dioxide gas.
- **Smelting**: This is a process that involves melting the ore to extract the metal, usually involving a reducing agent. It is not specifically for converting sulphide to oxide.
- **Leaching**: This is a hydrometallurgical process that involves dissolving the ore in a solvent to separate the metal from impurities. It does not convert sulphides to oxides.

2. **Analyzing the Options**:
- **Option 1: Calcination** - This is incorrect because it is not used for sulphide ores.
- **Option 2: Roasting** - This is correct as it specifically applies to the conversion of sulphide ores to metal oxides.
- **Option 3: Smelting** - This is incorrect as it is not a process for converting sulphides to oxides.
- **Option 4: Leaching** - This is also incorrect for the conversion of sulphides to oxides.

3. **Conclusion**:
- The correct answer is **Option 2: Roasting**. This process effectively converts sulphide ores into metal oxides by heating them in the presence of oxygen.

### Final Answer:
A sulphide ore is converted into metal oxide by the process of **roasting**.