Description of the use of thermite in WWII

PETER'S NEW YORK, May 12, 2012--I recently procured a volume entitled "Modern Chemical Discoveries" by Richard Clements (1954, E.P. Dutton, 290 pgs.). It describes the advent of many new industrial processes at the time, and explains the manner in which they operate. It is a book targeted to the educated layman.

In a chapter entitled "Some metals and their compounds," it describes what we generally know as thermite, the nature of the chemical reaction associated with it, and its effects (p117-118).

"A mixture of aluminum powder heated with the oxide of another metal gives a violent chemical reaction. The aluminum is converted into oxide while the other metal is left in the metallic state. The action is so violent in some cases, copper oxide, for example, that a kind of explosion occurs and part of the metal is volatilized. Chromium is obtained in this way in a pure state, as also manganese which previously had been known only in combination with carbon or iron.

"An ingenious application of this property of aluminum is found in the "thermit" process. A mixture of ferric oxide with aluminum powder is put in a crucible with a removable bottom, When a fuse is lit the whole mass glows and in a few minutes a layer of molten iron sinks to the bottom of the pot and can be run off into a mould. The method is used for the repair of broken castings or to join the ends of rails without removing them. A mould around the rail-end holds the melted metal, and after solidifying the excess iron can be cut or ground away. The temperature produced in the mixture is about 3,500(deg)C. and is sufficiently high to melt every known metal. The thermit process is used in many incendiary bombs, as once the reaction is started it cannot be stopped, as many fire-fighters discovered during the air-raids on London and other cities in the last war."

What particularly alarmed me about this description was the mention of the fact that once the reaction is started, it cannot be stopped. One remembers the fires that burned on for days in the midst of the rubble of the World Trade Center towers in the aftermath of the events of September 11, 2001, and the tremendous heat released. It is unfortunate that we cannot find video evidence of what went on beneath the rubble that fed these prolonged heat-generating fires. Undoubtedly, video footage of these conditions exists, and if we were to obtain them, it might shed light on the conditions within the rubble piles and the cause thereof. Physical evidence, such as samples from the hot pile of rubble, would also be of great interest to researchers.