explain the principle of zone refining
Principle Impurities are more soluble in the molten state of metal (the melt) than in the solid state.
In this process, a circular heater is fixed at one end of a rod of impure metal.
As the heater moves, the molten zone of the rod also moves along with it.
As a result, pure metal crystallises out of the melt, and the impurities pass to the adjacent molten zone.
This process is repeated several times, which leads to the segregation of impurities at one end of the rod. Then, the end with the impurities is cut off.
The method of purification is used to obtain the metals.
1. A circular movable heater is placed at on end of the impure metal rod.
2. Placed heater slowly moves across the metal rod and melts at that specific point of heating.
3. Then the pure metal crystallises while the impurities pass on the melted zone.
4. This process is repeated several times.At one end,the impurities get concentrated and removed.
5. Thus high pure metals are obtained by this process.
It is used for ultra metals or semiconductor
Ex- Ga,Ge and Si