Zone refining is a technique used primarily for the one of the following process

Options

A. Alloying
B. Tempering
C. Sintering
D. Purification

Answer

**Step-by-Step Text Solution:**

1. **Understanding Zone Refining**: Zone refining is a technique used to purify materials, particularly metals and semiconductors. It is based on the principle that impurities tend to concentrate in the molten phase of a material.

2. **Initial Concentration**: Before applying zone refining, the ore is concentrated to remove gangue particles (impurities). This process leaves us with a concentrated material that still contains impurities.

3. **Purification Process**: The concentrated material is then subjected to zone refining. In this process, an impure rod (for example, germanium or silicon) is heated using an electric heater while it is moved along its length.

4. **Movement of Impurities**: As the heater moves along the rod, the material melts in the heated zone. The impurities, having a different solubility in the molten phase compared to the pure material, tend to move ahead of the molten zone.

5. **Separation of Pure Material**: Eventually, the impurities gather at one end of the rod, while the pure material solidifies behind the molten zone. The end with the impurities can then be cut off, leaving behind a highly purified material.

6. **Applications**: Zone refining is particularly important for materials that require high purity, such as silicon used in solar cells and germanium used in semiconductors.

7. **Conclusion**: Therefore, the primary purpose of zone refining is purification of materials, making it a critical process in the production of high-purity elements.