I have an O2 cylinder in my garage that runs 3000psi when full. Welding gas, y'know. Every mechanic's shop has one. Hydrogen is also used as a welding gas, it is commonly stored and shipped in the same truck as the O2 cylinders. Along with propane, acetalene, MAP gas, etc.
Aluminum is -very- expensive to produce compared to liquefied gas. Its refined from bauxite by electrolysis. They put the Al refineries next to hydroelectric dams instead of next to the bauxite mine, that should tell you something eh?
Not saying it couldn't work nicely as a propellant for use on the moon or asteroids, where water ice and recoverable aluminum could be found. Thermite could too. Just saying calling it green is tripe.
Although I have to say, the thought of refining pure aluminum on the moon is PURE science fiction. Electrolysis of molten rock, hard to do in a space suit with a refiner unit hauled up from Earth, right? Electrolysis of the ice for use as a hydrogen/oxygen rocket would be easier, yes? Solar panel, couple plastic bags and a compressor pump.