Question

Chlorine is used in:

• A. purification of iron
• B. purification of aluminium
• C. purification of gold
• D. purification of copper

Answer 1

Answer: (C)

How the Miller Process works

$\to$ Gold is insert to a majority of chemicals. Its impurities (such as zinc, copper and iron) are not.

$\to$ The first step in the Miller Process is to use an induction furnace to melt the gold sample in a crucible.

$\to$ Once the sample is liquefied pure chlorine gas is blown across it.

-This causes the impurities to form chlorides which rise to the top of the crucible.

Option $A$ is correct.

The Miller process is an industrial-scale chemical procedure used to refine gold to a high degree of purity (99.95%). This chemical process involves blowing a stream of pure chlorine gas over and through a crucible filled with molten, but impure, gold. This process purifies the gold because nearly all other elements will form chlorides before gold does, and they can then be removed as salts that are insoluble in the molten metal.