slag

“There were high concentrations of slag in these, which is a glass-like material that makes them maybe a little bit more brittle in the cold,” she says.

The Cambridge researchers found that used cement is an effective substitute for lime flux, which is used in steel recycling to remove impurities and normally ends up as a waste product known as slag.

The Cambridge team spotted the composition of used cement is almost exactly the same as the slag used in electric arc furnaces.

Smithy and Mara were busy sorting the metal slag that they would have to leave behind and the tools they could pack onto the camels.

Collins added: "Louis, don't be slagging off my boys. They're not vile or they wouldn't be in my hot tub."