Efficient Production of Iron(II) Oxide (Fe2O3) : 4 Steps ...
Continue until you have enough coarse aluminum powder to fill the blender ½ to 3/4 full. Add it all back to the processor and let it process at full speed for several minutes. I always thought that blue/black iron oxide had a higher ratio of oxygen than red/brown iron oxide (simple rust) and would be better for using to make thermite.