Apollo20, (and Steven if you're reading this),
For the sake of discussion, let's say the iron microspheres WERE formed from thermite planted in the WTCs.
How did Si get in the iron microspheres?
I have put forth the notion that thermite was planted in some perimeter box columns at impact floors. I have describes several possible modes, ranging from just a little thermite to heat the bolts, to columns packed with thermite so that the (not-welded) bolt-access-hole covers would pop off from internal pressure upon ignition of the thermite, and the burning content would be spewed out onto piles of debris (thereby creating some of the long-lived, energetic "fires on piles of debris").
But why wouldn't the thermite burn through the bottom of the column?
Somewhere in the debris field that is my writings is a scenario in which the box columns were filled with sand or silica to the
bottom of the lower bolt-access-hole (so there is about a foot of sand in the column). Thermite was then packed on top. When the thermite was ignited by All-Weather Max Photon-brand Thermite Fuse right near the bolt-access-hole, pressure popped off the cover, and the column became like a bulk thermite dispenser.
I have proposed that WTC2's 10-minute metal fire - which is located exactly at Column 301/81's bolt-access-hole - is in fact burning thermite being spewed onto the collected debris. (Note that the burn front is
outside of the column, or right at the hole. Little thermite burns
inside the column.)
The sand or silica source next to the burning thermite might account for:
- Thermite being able to be packed in columns, without melting the columns;
- Si being found in the iron microspheres (which formed as the thermite burned AND as the towers collapsed and dispersed molten material);
- No evidence of iron in the bottom of the columns (not that anyone looked).
Not
TAM simple, but hey, even Apollo20 said the formation of iron microspheres (Now with Si ! ) below iron's melting point of 1536 C is a - Class? - that's right - a "complex process."
(I really have quite an imagination, don't I?)
Max