What happens to atium once it is burned?

[Allomancer Alex]

I was wondering what happens to atium once it has been burned? As far as I am aware atium is the body of ruin/ati and is physical form of Investiture. I understand that "Investiture works in a similar fashion to energy in that it follows its own laws of thermodynamics and that it is not possible to destroy Investiture; it can only be redistributed."

Preservation had the mists snap people to become atium mistings so that they could burn away the atium cache so that ruin couldn't get a hold of it. But, where does that physical Investiture go to (e.g., the cognitive or spiritual realm?) and why can't ruin access it after it has been "redistributed"? 

 

[The One Who Connects]

4 minutes ago, Allomancer Alex said:

I was wondering what happens to atium once it has been burned?
But, where does that physical Investiture go to (e.g., the cognitive or spiritual realm?) and why can't ruin access it after it has been "redistributed"?

So to answer your question, have a timeline describing how everything was Preservation's fault. (The highlighted portions are your proper answer)

1. When Preservation attacked Ruin, he "kind-of" splintered him. The chunk of Ruin's power that produces Atium is/was entirely separate from the rest of Ruin.
2. Preservation wasn't going to absorb Ruin's power into himself, so he forced that chunk of power to produce Atium instead. (Preservation knew how to make Lerasium from his own power, so jury-rigging Ruin's power to do the same isn't too unreasonable.)
3. Normally, the power would return to Ruin after being burned, but using that separated piece of Ruin, Preservation was able to short-cut it directly back into Atium after it was burned.

In short, Ruin could not access that stolen piece of his power until Preservation was no longer blocking him. And he couldn't recover the power that was turned into Atium unless he physically obtained that Atium himself.

By burning it all, Ruin would have to then get rid of Preservation in order to obtain his stolen power. He never had time to do so, since both he and Preservation died shortly afterwards. With nobody blocking him, Harmony has since recovered this piece of power, and the Pits & the Well are no more.