Ever burnt a piece of steel wool? And more slowly, rusting, oxidation, is a slow variation of the same process. Here's a CBC Quirks and Quarks podcast on using iron as alternate fuel: Alternative Energy Enters the Iron Age - Home | Quirks & Quarks with Bob McDonald | CBC Radio
Interesting idea. Would be helpful to see the energy available in a set mass or volume of powdered and reduced iron. Then there is the technical issue of controlling spontaneous oxidation of the iron, which would otherwise happen at a pretty fast rate for powdered iron given the vastly increased surface area. Edit: read the text, but haven't listened to the podcast yet, maybe covered there.
Burning iron powder is a bad move. I don't know how much energy it takes to make iron powder but I'll bet you put in a lot more than you can get out of it and it is a filthy dangerous job. Iron powder goes everywhere and wherever it lands it rusts. The asphalt that paved the street rusts, When it lands on your car it bonds and rusts. A very good wax job and quick removal are about the best you can do but you'll probably end up compounding the car. I worked for a brief period loading and hauling bricks from the plant. At the end of the day the mucous in my nose was gray. The iron powder that makes it into your lungs will have a field day. Do you think it is any better than inhaling coal dust? The plant in Cinnaminson, NJ closed. Production was moved to Milton, TN or maybe even elsewhere by now. The powder is used to make automotive engine parts. Powders burn. Static electricity can ignite the dust in a granary. Edison's EV batteries used iron and were warranted for 4 years. It's a great demonstration for science class but there are more efficient and economical ways to generate and store power.
Not too many additional details in the podcast. A few other thoughts: -a lot of further energy would also be required to pulverize the reduced iron from iron ore (oxide) that would be smelted -that process would have to be done at a massive scale under anaerobic conditions -oxidizing iron to release heat for power generation may be more practical at the level of a power station or large ocean vessel than onboard a motor vehicle -again would need to see process energy inputs/outputs and efficiencies, but would this be a better alternative than hydrolysis for H2?
actually, for a long time i thought pulverized aluminum would be a great source of energy too. anyone played with thermite?
I hope people here mean 'storage', not 'source'. Yes, aluminum and other materials can theoretically be used for metal-air batteries. But none of these things (aluminum, iron, hydrogen, batteries, etc.) are found naturally on Earth in forms useful as energy sources. They can store energy obtained from some other source, but the natural forms are already in the drained condition.
..finely divided metals on alumina is what many catalysts are, such as catalytic converter. So you could have giant reactors with say 10% iron oxide (or whatever metals works best) on alumina pellets, and make H2 via electrolysis to reduce it to Fe at about 750F and 1000 psig H2, and then introduce air, or better yet O2 from the electrolysis, to burn it back to the oxide. This is pretty much standard stuff in industry, but hard to believe it would be a good energy storage technique.
