This makes no sense to me.

Iron/steel production is one of the largest individual sources of co2 emissions and uses a lot of energy.

And then to just burn it back into iron ore for energy - At best you'll only get back the energy you expended to refine it in the first place.

Assuming they are burning scrap, it would surely be better to melt it down and recycle it as steel.

As energy storage, it may well have more energy per liter than gasoline, but it weighs many times more. There are surely better options - even in the same category, eg aluminium?