Whats the ratio for iron oxide and aluminum powder for making thermit? ?

It depends on which iron oxide, and also ratio of moles or mass.


Most common: 8Al + 3Fe3O4 -%26gt; 4Al2O3 + 9Fe


moles 8:3. mass 8*27:(9*55.845+12*16) = 216:694.605 = 0.31:1





With rust: 2Al + Fe2O3 -%26gt; Al2O3 + 2Fe


moles 2:1. mass 2*27:(2*55.845+3*16) = 54:159.69 = 0.338:1





In general: 2yAl + 3FexOy -%26gt; yAl2O3 + 3xFe


moles 2y:3. mass 2y*27:(3x*55.845+3y*16) = 54y:(167.535x + 48y)





Then of course there could be a mixture of iron oxides.

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