Question

I recently read an article on Thorium reactors by John Suchocki (unfortunately, a link would only lead to a paywall). In it, he mentions that in the production of Thorium reactors, The thorium is first blended with fluoride salts to bring the melting point to a relatively cool 360°C. How does this work? Shouldn't adding salts raise the melting point of a substance?

Answer 1

Adding fluoride salts to thorium in the production of thorium reactors lowers the melting point of the mixture compared to pure thorium.

Step-by-step explanation:

When thorium is blended with fluoride salts in the production of thorium reactors, the melting point actually decreases, rather than increasing.

This is because the addition of salts changes the intermolecular forces between the thorium atoms, affecting their ability to attract and hold on to one another.

In the case of thorium fluoride salts, the bonds between the thorium and fluoride ions are relatively weak, compared to other types of bonds, such as metallic or covalent bonds.

As a result, the thorium-fluoride mixture has a lower melting point than pure thorium.