Question

Explain zone refining of a crude metal with example

Answer 1

Zone refining:- This method is based on the principle that the impurities are more soluble in the melt than in the solid state of the melt.

A circular mobile heater is fixed at one end of rod of impure metal. The matter zone moves along with the heater which is moved forward. As heater moves forward, pure metal crystallizes out the melt and the impurities pass on into the adjacent matters zone. The process is repeated several times and the heater is moved in the same directions.

Ex: Ge, Si, B, Ga, In