The method not used in metallurgy to refine impure metal is :

Options

A. Mond's process
B. Van Arkel process
C. Liquation
D. All are used

Answer

To determine the method not used in metallurgy to refine impure metal, we will analyze the given methods one by one.

### Step 1: Analyze the Mons Process
- The Mons process is a method used to purify nickel. In this process, impure nickel is treated with carbon monoxide, forming nickel tetra carbonyl, which on heating decomposes to yield pure nickel and carbon monoxide.
- **Conclusion**: The Mons process is indeed used for refining metals.

### Step 2: Analyze the Wener-Argyl Process
- The Wener-Argyl process is used for the purification of titanium and zirconium. In this method, impure titanium is treated with chlorine, resulting in the formation of titanium tetrachloride. Upon heating, this compound releases chlorine and yields pure titanium.
- **Conclusion**: The Wener-Argyl process is also a method used for refining metals.

### Step 3: Analyze the Liquefaction Method
- The liquefaction method involves heating a mixture of ore and impurities. Since the impurities generally have a higher melting point than the ore, the ore melts and separates from the impurities. This method is commonly used in metallurgy to separate metals from their ores.
- **Conclusion**: The liquefaction method is a purification technique used in metallurgy.

### Step 4: Identify the Method Not Used
- The question asks for the method not used in metallurgy to refine impure metal. After analyzing the Mons process, Wener-Argyl process, and liquefaction method, all three methods are indeed used in metallurgy.
- Therefore, the correct answer is **option d: all of the above**.

### Final Answer
The method not used in metallurgy to refine impure metal is: **all of the above**.

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