I wonder how they discovered this for the first time, must have involved copious quantities of wodka. It looks like the slag from a steel mill or iron furnace. Also, to me, the protective clothes look like asbestos too.
In Soviet Russia men are fireproof. It's perhaps the most impressive demonstration of the Leidenfrost effect I've ever seen. The best I've done is sticking a finger in liquid nitrogen...
I think the risk for getting burns in his face is greater than on his hand, as he does not wear a face shield. Dropping molten iron on a wet surface (his wettened hand), even in a fraction of a second can result in a steam explosion, splattering droplets of iron around, including into his face.
Didn't know, I had to google it and Wikipedia links to this video. "done by professionals" they say...