The 9/11 Forum

"Nanothermite" in WTC Dust: Current Status (and Future Prospects)

1.0 Introduction

As described in an Open Chemical Physics Journal article published in April, 2009, N. Harrit and S. Jones, (H&J), and seven additional authors, claim to have found “nanothermite” residues in samples of WTC dust. The “active” residues of interest are found in WTC dust samples by a simple magnetic separation technique and typically constitute less than 1 % of the total collected dust. According to H&J, most of the magnetic material found in WTC dust consists of iron-rich microspheres. However, there is also an allegedly “thermitic” component of the magnetically extracted material that is in the form of small bi-layered red/gray chips, typically less than 1 mm in length and less than 100 microns thick. X-ray analysis shows these chips contain mainly Fe, Al, Si with variable amounts of C and O.

The notion that red/gray chips in the WTC dust are “nanothermite” is based on comparisons of H&J’s chips to certain so-called “energetic materials” described in literature reports from several specialized research laboratories around the world. These newly developed nano-thermitic materials are of particular interest to the military because of their potential use in incendiary and explosive devices. It is therefore to be expected that a great deal of the data on nanothermitic materials originates in weapons research facilities such as the Lawrence Livermore Laboratories. Unfortunately this also means that nano-thermitic materials are not readily available to independent researchers such as H&J. Nonetheless, H&J insist they have found “nanothermite” residues in samples of WTC dust. In the following write up we shall look at H&J’s evidence for this claim and consider the implications of their discovery.

2.0 Why Nano-Thermite and not Simply Thermite?

The energy stored in a thermitic material may be calculated from the amount of iron oxide and aluminum in a sample and the heats of formation of the species in the reaction: Fe2O3 + 2Al = 2Fe + Al2O3. However, the rate at which this energy is released depends on how well the Fe2O3 and Al are mixed. It is well known that aluminum must be finely divided to react efficiently with Fe2O3, but even micron-sized aluminum reacts quite slowly and is difficult to ignite; this has greatly limited practical applications of thermitic materials since their discovery about 100 years ago. However, this all changed in the 1970s when Russian scientists developed an electro-exploding wire technique for the synthesis of nano-aluminum. This material found immediate applications as a replacement for micron-sized aluminum powders in solid rocket propellants because it was found that nano-aluminum effectively doubled the burning rate and greatly increased the thrust of propellants made with standard 20-micron aluminum powder.

At the present time there are many industrial scale processes that have been developed for the production of kilogram quantities of nano-aluminum, for example: electro-exploding wire; DC plasma torch; inert gas condensation synthesis and decomposition of alane adducts. The final size and morphology of the nano-aluminum product varies not only between these different preparation techniques but may also be finely controlled via process parameters such as the pressure and nature of the cover gas. Given that relatively simple techniques such as chemical vapor deposition have been available since the 1970s for the production of nano-sized metal oxides, it is hardly surprising that by the 1990s nano-aluminum was being mixed with these oxide powders to produce experimental thermitic composites.

A survey of the literature on aluminum-based reactive composite materials such as nano-thermite, (sometimes also called “super-thermite”), reveals that many formulations have been developed and tested; however, as far as I know, none are commercially available. Nevertheless, it appears that formulations that have been successfully prepared differ largely in how the aluminum and oxide particles are mixed, which in turn influences the size of the nano-domains in the final product. Some of the more favored preparatory techniques are: ultrasonic agitation and evaporation in a solvent bath; sol-gel processing involving the suspension of hydrated metal oxides in ethanol with the addition of propylene oxide as a gelation agent; vapor deposition; arrested reactive milling, etc. It has also been reported that the aging characteristics of a nano-material strongly depend on the preparation technique. It should be mentioned that many other oxides, besides Fe2O3, have been used to make nanothermites, e.g: MoO3, CuO, WO3, etc.

3.0 Why do Harrit and Jones Claim their Red/Gray Chips are Nanothermite?

Harrit and Jones base their identification of the WTC red/gray chips as a “nanothermitic material” on three observations:

1. The material’s composition: mostly Al, Fe, O, Si, and C.
2. The presence of intimately mixed sub-micron particles rich in Al and Fe.
3. The ignition behavior of the chips.

Observation No. 1 (concerning composition) is hardly definitive since the list of identified elements describes the composition of a mixture of many very common building materials known to have been present in the Twin Towers. In addition, Si is usually not considered to be an ingredient of a conventional thermite. Probably the most important identifier for an iron oxide/aluminum-based thermitic material is the presence of metallic (elemental) aluminum. Unfortunately, H&J’s X-ray analysis data do not provide unequivocal evidence for the presence of metallic aluminum and additional (X-ray diffraction) analyses are evidently required to resolve this question.

Observation No. 2 (concerning particle size) is also not definitive because of the previously noted issue of the variability of nanothermite formulations. H &J appear to believe that the red/gray chips they found in the WTC dust were most probably made by a sol-gel processing technique using the methodology reported by Tillotson, Gash, Simpson and other scientists at Lawrence Livermore. However, the Fe2O3/Al nanocomposites reported by these Livermore authors invariably contain ultra fine grain (UFG) ~ 25 nm diameter Al metal particles. By comparison, H&J’s red/gray chips contain only Al platelets approximately 1 micron in diameter and 50 nm thick. These Al particles are too large to be correctly classified as nano-scale material.

Observation No. 3 (concerning the ignition behavior of the red/gray chips) is crucial to H&J’s case for nanothermite in the WTC dust. H&J claim that the WTC chips ignite at temperatures as low as 430 deg C and emphasize that this minimal heating managed to produce iron-rich microspheres. This demonstrates that low temperature ignition of red/gray chips involves the formation of molten iron - a key characteristic of a Fe2O3/Al-based thermite reaction.

In June 2009 partial corroboration of H&J’s results was provided by Henry-Couannier, (HC), an independent researcher working in Marseille, France. HC was using WTC dust from Warren St, NYC, a sample apparently not tested by H&J. However, while HC has confirmed H&J’s observations concerning the chips composition and particle size, he has reported difficulty in igniting material extracted from his WTC dust sample even when heated to 900 deg C. This has prompted Harrit to speculate that the chips in HC’s sample may have lost their initial reactivity, perhaps as the result of exposure to rain prior to sampling. However, the divergence of H&J and HC’s results also suggests the possibility that there are different types of magnetic chips in the WTC dust.

4. Discussion

Let’s assume, for the sake of argument, that something resembling one of the nanothermitic materials reported in the scientific literature was in fact deployed at the World Trade Center during 9/11. In order to understand why nanothermite might have been used to bring about the destruction of WTC 1 & 2 we need to consider the properties and reported uses of nanothermites. A survey of published information on reactive nano-materials leads to a clear distinction between nanothermite formulations that behave largely as incendiaries and formulations that exhibit the properties of high explosives. This distinction is crucial to the present discussion for two reasons:

(i) It is apparent that the world’s supply of nanothermitic materials has always been quite limited, especially prior to 9/11.
(ii) It is well documented that nanothermites alone are not a practical high explosives. Thus we read in a recent article by E. L. Dreizin in Progress in Energy and Combustion Science:

“Combustion of nanocomposite thermite was found to produce gas pressures that are inadequate for ignition primers; however, the combination of nanocomposite materials with conventional energetic formulations was found to present a promising approach for future practical devices.”

These practical limitations on the imagined deployment of a simple nano-scale metal/metal oxide mixture in some clandestine demolition scenario at the World Trade Center has led H&J to admit that if nanothermite was in fact used during 9/11, it had to be in conjunction with high explosives. Information on this topic is scant of course, nonetheless it appears that high explosives such as TNT and HMX have indeed been used in conjunction with nanothermites to enhance the blast effects of pyrotechnic devices.

Interestingly, the quantitative DSC results reported by H&J support the notion that the red/gray chips in the WTC dust contain more than Fe2O3 and Al as their active ingredients. However, this by no means proves anything about the possible use of super-thermite – which is essentially organically-boosted nanothermite - at the WTC. This cannot be verified until the organic content of the red/gray chips has been determined. This would require extensive chemical work-up and characterization of red/gray chip material using techniques such as GC, GCMS, FTIR and liquid chromatography. It is unclear at this time if the H&J team has the resources to undertake and successfully complete this type of detailed forensic analysis. Perhaps one day some other intrepid band of 9/11 researchers will surprise us all and tell us what organic materials are in the red/gray chips! However, until that happens, H&J’s proposal that pre-planted nanothermite was used to destroy WTC 1 & 2 will remain a riddle wrapped in a mystery.....

Nice article, though I have a problem with ". By comparison, H&J’s red/gray chips contain only Al platelets approximately 1 micron in diameter and 50 nm thick. These Al particles are too large to be correctly classified as nano-scale material."

This is like saying that "I put a thick coat of paint on, because I painted the side of a barn instead of the porch door". It's not an accurate statement, because we generally associate the thickness with the smallest dimension of the paint coating, not width or height.

In terms of chemical reactions, I don't have any quantitative arguments to present, but intuitively, it's a slam dunk that reaction rates are dominated by the shortest distance to the outside, not the longest. Also, please recall that "hoop strength" of spherical Al particles is in the GPa range. While I've been warned not to take figures for microscopic figures as though they applied to a macroscopic object, recall also that the figure of a planar morphology of Al Oxide is in the MPa range. So, cracking it is easier, which I think will translate into a lower ignition temperature, and a less explosive formulation.

ETA: I posted most of your concluding paragraph on Professor Jones' blog at 911 blogger, under the article Exchange of emails (March 2009) with Robert Erickson, producer of the National Geographic special on 9/11

Thanks Metamars .....

On the issue of the size of the Al particles in H&J's red/gray chips, my main point is that the Al is present as platelets and it appears none of the published information on nanothermites refers to the Al being in the form of platelets. Certainly the Lawrence Livermore scientists appear to always use more or less spherical Al particles.

Thus H&J need to consider WHY Al platelets were used in the WTC material, and WHO makes Al platelets.

Dr.G please, see this

http://911blogger.com/node/20998

Recently, I decided to check out these independent researchers, because I think it's important for followers of this scientific research to understand that what prof. Jones, Harrit and others did, is to conduct experiments, that can and should be repeated by others. It's important to note that not all red/gray chips found in the dust actually ignite, and some dust samples only contain "inactive" material. It has been stated before by prof. Harrit that the quality of the red/gray chips apparently deteriorates over time. Furthermore, it is becoming increasingly difficult for these researchers to obtain WTC dust samples

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But the other interesting thing about these chips that really kind of shows you that they are the nano-thermite, is that when you take these small little chips and you ignite them... If you woulda take one and grind it up beforehand; just the red layer... There is no free iron in it. When I say free iron, like, you know, little beebees of iron metal, that exist in these. You know it's iron oxide, it's not free iron. But when you ignite one, and then you break it up afterwards, you basically find these little droplets, although they're not actually I mean, as a portion of the total volume of the chip they rather significant, but they're still small because these chips are small. But you basically produce molten iron, which then when it cools down again becomes these droplets of iron. As well as the whole the nanostructure that I talked about there, kind of gets destroyed in large part during this combustion process, but some of it at the end is still there and all these inner chambers basically are coated with a very thin metallic layer after it freezes again, so... There is few interesting things that go on in them.

No, I basically have a setup where I have a stainless steel resistive heating element, that I basically use that's ... oh... what is it... It's about little less than a quarter of an inch across and I basically.. you know... using tweezers and micromanipulators or whatever put the chips basically in the center of the strip, and then by controlling the amount of electricity that flows through the strip, I can heat it up to pretty much any temperature that I want. I don't bring them, you know, anywheres near, you know, the temperatures to do anything harmful to them, but just up enough to basically get them to ignite, and they ignite in the region of... oh... somewhere a little over 400 degrees centigrade typically, and uhm.... When they ignite, you know, I basically have just recorded them burning and then after the fact you can open them up and look inside for these uh.. these iron droplets and films that I spoke of earlier.

and more in the text, so this guy did get the samples to ignite

Dr.G will you please try to get some of the dust for yourself?

EDIT: Is it possible that some of the chips just simply don't go of, because the nanoaluminium pasivation isn't perfect? What if some of them were in contact with air that most of nanoaluminium platelet is made of Al2O3?