My first thought when I read the headline was that a German firm had gone through to find a new substance for use in molten salt storage [1]. Reading through it, I was a bit disappointed that there doesn't seem to be any sort of waste heat recovery in place here, which is making me curious. Given that the molten aluminum needs cooled and shaped into ingots to be distributed to manufacturers, I'm curious if there is any sort of waste heat recovery system in place, and/or a system to pump that heat into any sort of a District Heating [2] sort of system. All that heating in the system has to go somewhere, and given the sizes of the smelting halls, it seems like it would be profitable to set some sort of system up.

[1] http://en.wikipedia.org/wiki/Thermal_energy_storage#Molten_s...

[2] http://en.wikipedia.org/wiki/District_heating