Pretty neat idea! My first concern is that iron is pretty heavy for a fuel. It looks like you get about 4.8kJ/g from burning iron, and somewhere around 10x that

Pretty neat idea! My first concern is that iron is pretty heavy for a fuel. It looks like you get about 4.8kJ/g from burning iron, and somewhere around 10x that for most hydrocarbons. In other words, I wonder if iron is so heavy that you pretty much have to do this burn/reduce cycle in close proximity of eachother. Useful for a battery maybe but not as much for a transportable fuel, except maybe for boats and trains