Question

Among the following options, a process for liquid-liquid separation is

• A. Smelting
• B. Roasting
• C. Sintering
• D. Calcination

Hint:

Associate key transformations with each metallurgical process: Smelting \(\rightarrow\) Melting \& Reduction (liquid metal + liquid slag); Roasting \(\rightarrow\) Oxidation (solid + gas); Calcination \(\rightarrow\) Decomposition (solid + gas); Sintering \(\rightarrow\) Agglomeration (solid).

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks to identify which of the given metallurgical processes involves the separation of two immiscible liquids.
Step 2: Detailed Explanation:
Let's analyze each option:

• Smelting: This is a high-temperature process used to extract a metal from its ore. During smelting, the ore is heated with a reducing agent (like coke) and a flux. This results in the formation of two immiscible liquid layers: the molten metal and a lighter molten slag (composed of impurities and flux). The molten metal is then separated from the slag by tapping them off at different levels. This is a clear example of a liquid-liquid separation.
  
• Roasting: This process involves heating a solid ore (often a sulfide) in the presence of air to convert it into a more manageable form, typically an oxide. This is a gas-solid reaction and does not involve liquid-liquid separation.
  
• Sintering: This process involves heating fine particles of ore at a temperature just below their melting point to cause them to agglomerate into a porous solid mass called sinter. This is a solid-state process.
  
• Calcination: This involves heating an ore (like a carbonate or hydroxide) in the absence or limited supply of air to decompose it and drive off a volatile component, such as carbon dioxide or water. This is a thermal decomposition process, a solid-gas reaction.
  

Step 3: Final Answer:
Based on the analysis, smelting is the only process among the options that involves the separation of two immiscible liquids (molten metal and molten slag).