Scott A. Seymore. Age 11. of Bishop.CA

Can we take neon xenon and krypton from the air?

Most of the air is made up of nitrogen and oxygen. Nitrogen takes up about 78 percent of air space.. oxygen about 29 percent. That leaves only one percent for other gases. And most of this is filled with carbon dioxide. Traces of other gases share the rest‑ of the space between them. We call them the rare gases. which is not surprising.

First of these gases to come out of hiding was helium. This was in 1895.. For almost 30 years it was known that helium was present in the sun.  Then smidgeons of it were discovered in our atmosphere. Three years later. in 1898. four more rare gases were pulled out of the air. There was argon. the lazy one. It was so named because it refused. and still refuses. to react with any other substance.

Then came neon the new one. Xenon, the stranger was discovered before there was time to get used to neon. And almost at once krypton. the hidden one was forced out of hiding. The job of separating these gases from the air was cone by Sir William Ramsey who had already isolated helium. It was a complicated job of weighing chemical processes.

Nowadays we separate the rare gases in a complex machine. Ordinary air is compressed and chilled. Each gas turns to liquid at its own special temperature near its boiling point. The different gases in the air are separated with one piece of machinery.

Compressed air is pumped into a chamber. Suddenly this packed air is expanded by a power driven engine. When air expands. it loses its heat. And coldness is nothing but the absence of heat. The air is chilled from a gaseous to a liquid state. which is very very cold indeed.

The. liquid air is sent to the bottom level of a tall cylinder. Inside. the cylinder is fitted with a ladder of platforms. Some of the liquid air is piped around to chill the whole cylinder chamber. The rest of it is separated into its various gases on its way up the ladder.  Liquid oxygen is piped off near the bottom. Kryton and xenon are piped  off together from the same area. They are separated from each other later by chemical processes.  Argon, is lead off from a pipe higher up the cylinder. Neon. helium and nitrogen are lead off from the top of the cylinder.

The. nitrogen is separated first from this mixture of three gases. Then the neon and helium are separated by a process of charcoal and low temperatures. And after all this work. the manufacturer can sell a litre of rare neon gas for around $5.50.

The rare gases are still rare. They are still difficult and expensive to separate from the air. Neon. the new one. is no longer new. It adds its red‑orange glow to the signs of Main street. Krypton. the hidden one. helps with Christmas tree lights and high speed photography. Even argon. the lazy one. is forced to do a nights work. It helps in the neon tubes. Xenon. the stranger. is rarest and most expensive. Most of it is saved for use by polar explorers. For it behaves well in the lamps needed through the bitter Artic winters.