Whenever the media get their hands on an amateur bomber, they turn and twist stuff around faster and harder than the large hadron collider.
Acetone peroxide becomes "the mother of satan", fertillizer is a national threat and aluminum powder is a "secret ingredient" that makes bombs super-duper dangerous with a twist. Yeah I'm snapping at you, wired ...
Aluminium has been used for ages to increase the density of explosives as well as correct or intentionally throw off the oxygen balance. Aluminium, Al by it's scientific name has seen extensive use by amateur high energy chemists in compositions such as ANAl wax, ANNMAl and many more. The military uses it in huge crude explosives. It is not a secret, it is common practice for military ordonance and amateur concoctions alike.
Stop with the PSH! Needlessly scaring people to terrorist acts defeats the purpose of terrorism, don't do their job for them!