@blackoverflow @NO_KINGS_muc Yes, and it might also prove that ICE is less cool than they think they are!

@NO_KINGS_muc Sadly Lava has a specific heat capacity of <1kJ/kgK, while Ice has slightly above 2kJ/kgK, a specific melting energy of 334kJ/kg, Water then has a specific heat capacity of over 4kJ/kgK, and a specific vapourizing energy of about 2200kJ/kg.

Since hot lava is not just going to melt ice on contact, but vapourize the water: Suppose you've got 1kg of 1200°C lava. This thus has an energy of less than 1500kJ.

Suppose you've got ice at -20°C. Then for each kg of ice you'll need over 20*2+334=374kJ to melt. So theoretically we could melt 3–4kg of ice. But since until say 200°C the molten water is going to evaporate pretty fast this means for ~1000kJ you need to also heat the water to 100°C (420kJ/kg) and vapourize it (2.2MJ/kg).

So all in all you'd have ~3MJ/kg of ice. So this 1000kJ can evaporate only ⅓kg of ice. The remainig 200kJ to 0°C will maybe rather melt the ice, but at this point you have only energy for melting a bit more than ½kg of ice. So all in all 1kg of 1200°C lava will only melt ~1kg of ice at -20°C.

So don't think this would be overly effective.