Some tax money, presumably. This may also be a case where the politically powerful push through things that give them personal gains but which bring little public gains. However, it's plausible that they simply misjudged the situation.

Ricardo's ideas about comparative advantage do not factor in destroying things that are not and to a large extent can not be valued in monetary terms. Otherwise, I don't really know about comparative advantage. Aluminium smelters are not the industry of tomorrow and I doubt that Iceland will gain much of it.