mostly iron and carbon but there are three other elements.
molten slag mainly contain CaO, MgO, FeO, SiO2 etc.
it contains minerals, solid rock, and Animal poo that has decended to the level of molteen rock with no suclight to decompose it
In molten sodium chloride the free moving particles are Na+ and Cl- ions, during electrolysis sodium ion moves towards cathode and chloride ion towards anode.
Molten wax is hot. It can give you a burn, even though it might be a low grade one.