Spontaneous Combustion of Aluminum
Spontaneous Combustion of Aluminum
(OP)
Had a liitle fire that I think may have been caused by spontaneous combustion.
Scenario:
Aluminum "sawdust", chips and small pieces deposited in a plastic bag in a plastic trash container. Could easily have been 50 lbs. or more. It was probably contaminated with oils, water and maybe even cement dust and/or drywall mud dust.
Nobody was nearby when it happened (at night).
My Web search says that this may be possible. Can any of you chemicals help this structural and verify that this is indeed a very real possibility.
Thanks for any help
Scenario:
Aluminum "sawdust", chips and small pieces deposited in a plastic bag in a plastic trash container. Could easily have been 50 lbs. or more. It was probably contaminated with oils, water and maybe even cement dust and/or drywall mud dust.
Nobody was nearby when it happened (at night).
My Web search says that this may be possible. Can any of you chemicals help this structural and verify that this is indeed a very real possibility.
Thanks for any help
RE: Spontaneous Combustion of Aluminum
Orenda
RE: Spontaneous Combustion of Aluminum
I did that and got the "maybe"
Kind of hoping for a more definitive answer... or "maybe" is all I will get....
RE: Spontaneous Combustion of Aluminum
Can only say maybe. Possibly, very sharp thin edges catalyzed the oxidation of oil, picked up some heat & then ignited. But, note that in the thermite reaction, a magnesium ribbon is used to ignite the reaction (between aluminum powder & iron oxide).
Generally, aluminum powder is considered hazardous for particle diameters < 420 microns (0.0168"). See
Recommendations for storage and handling of aluminum powders and paste, 4th Edn., The Aluminum Association (2006). Free.
http://ww
National Fire Protection Association (NFPA) standards:
NFPA 651, Standard for the Machining and Finishing of Aluminum and the Production and Handling of Aluminum Powders [651 seems to have been withdrawn & incorporated into 484 below]
NFPA 484, Standard for Combustible Metals, Metal Powders, and Metal Dusts. $42.50 non-member price.
ht
RE: Spontaneous Combustion of Aluminum
Thanks for your help... Since this was a "trash" or "scrap" type fire that burned up - no one will ever know exactly what was in the container.
So "MAYBE" is probably as good an answer as there is.
What now needs to be done - is to establish guidelines to prevent any repeat.
Thansk again.
RE: Spontaneous Combustion of Aluminum
You could:
** Use metal waste containers for chips (this may be a legal requirement in your area anyway).
** Encourage your machinists to use higher feed rates. At ~.005" per tooth, you start getting frangible thick curled chips that fly away from the tool and don't wrap around it in "birds nests", at least in 20xx aluminum. And you get your parts sooner.
Mike Halloran
Pembroke Pines, FL, USA
RE: Spontaneous Combustion of Aluminum
There is a greater chance that the oil and solvents along with some rags was the ignition source. Many light oils and solvents have ignition temps plenty low for this.
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RE: Spontaneous Combustion of Aluminum
'does aluminium burn?'.
The answer is, of course, "No".
ht
Interesting paper, especially if you've heard (the common misconception) that the British destroyer Sheffield sunk by Argentina in 1982 was due to a burning aluminum superstructure: The Ministry of Defence says it was steel.
Anyway, solid-fueled rockets commonly use fine aluminum powder or flake for fuel, but the Al particles must be small enough that the ignition heat isn't carried away from the surface. As EdStainless says, ignition is pretty difficult.
I've even intentionally oxidized molten aluminum alloys up to 1400 oC. Due to the protective oxide film that forms on both solid & liquid Al, alloying with Mg or Zn is necessary for a reasonable reaction rate [but nowhere near 'burning'].
RE: Spontaneous Combustion of Aluminum
At the least we have made a few "house keeping" changes to insure that this remote possibility cannot happen.