“A fusion energy start-up claims to have solved the millennia-old challenge of how to turn other metals into gold.

Chrysopoeia, commonly known as alchemy, has been pursued by civilisations as far back as ancient Egypt. Now San Francisco-based Marathon Fusion, a start-up focused on using nuclear fusion to generate power, has said the same process could be used to produce gold from mercury.

In an academic paper published last week, Marathon proposes that neutrons released in fusion reactions could be used to produce gold through a process known as nuclear transmutation…

The most common experimental approach to fusion uses a device called a tokamak to heat two hydrogen isotopes — usually deuterium and tritium — to extreme temperatures so that they fuse to create helium and vast amounts of energy in the form of neutrons.

Most plans for potential fusion power plants aim to combine some of the neutrons with lithium isotopes in a ‘breeding blanket’ to create more tritium for future reactions.

Marathon’s proposal is to also introduce a mercury isotope, mercury-198, into the breeding blanket and use the high-energy neutrons to turn it into mercury-197.

Mercury-197 is an unstable isotope that then decays over about 64 hours into gold-197, the only stable isotope of the metal.

Rutkowski and Schiller say this means future fusion power plants that adopt this approach would be able to produce 5,000kg of gold a year, per gigawatt of electricity generation, without reducing the power output or tritium-breeding capacity of the system.”

From Financial Times.