The process of zone refining is used for `:`

Options

A. silicon
B. germanium
C. gallium
D. all the above

Answer

D

Explanation

This process is used when metals are required in very high purity, for specific application. For example pure Si and Ge are used in semiconductors and hence are purified by this method. Zone refining method is based on the principle that an impure molten metal on gradual cookling will deposit crystals of the pure metal, while the impurities will be left in the remaining part of the molten metal.