Producing Helium (He)

He: Helium

Lockyer (UK) discovered in 1868.

Abundance: 5.2ppm(in the air)

Radioactive disintegration of U and/or Th in rocks

Alpha emission (alomic nuleus of He) by alpha decay

Slow down and accept electon to be He in rock.

Diffuses into rock and trapped in natural gas.

Natural gas is mined.

Refined by fractional distillation or absorption.