1. Mick West

    Mick West Administrator Staff Member


    After reading how most of the insulation in the world trade center was "Slag Wool" (a type of mineral wool insulation made from iron refining) I wondered if it might have some iron microspheres in it. So a little searching led me to the above image, from:

    They are very interesting because they look like iron microspheres. But without checking with a magnet, it's impossible to tell. They might possibly be melted fibers with some carbon making them dark.

    Another possibility is lead. Some slag wool was made from lead slag - although it's not clear when that practice stopped. Seems to have still being going on the 1970s though
    Metabunk 2018-10-16 12-16-32.

    The "Fowler 1980" reference leads to:

    Which describes how the process creates spheres ("shot") which is separated from the wool
    Metabunk 2018-10-16 12-28-50.

    The shot here is slag though, not iron.
    Last edited: Oct 16, 2018
    • Informative Informative x 1
  2. Mick West

    Mick West Administrator Staff Member

    More on lead in slag wool:
    Construction of the World Trade Center towers was in 1968 to 1970