How much energy does it take to grind that iron to powder?
How much energy does it take to grind that iron to powder?
Not all that difficult and you only need to grind it once, the iron oxide falls out of the combustion chamber still in power form.
A fun story of early metal powder makers.
https://www.chemistryviews.org/details/ezine/11187437/Sir_Henrys_Secret_Pot_of_Gold__Part_2.html