DCHAS-L Archives Jun 30 2011 - Re: FW: Lithium Aluminum Hydride & friction as an ignition source

Elsevier’s HazMat Navigator (disclosure – I am the senior editor) addresses LAH friction sensitivity as follows:

Care is necessary in handling this powerful reducant, which may ignite if lumps are pulverised with a pestle and mortar, even in a dry box [Augustine (1968) a]. An actual explosion destroying the mortar, has been claimed as the result of attempting to grind down large pellets, though contributory factors seem probable [Schatzschneider (1996) a]. A rubber mallet is recommended for breaking up lumps [Gaylord (1956)

Based on Russ’ report, I am up-dating the LAH record in HazMat Navigator to reflect an increased awareness of the friction sensitivity.

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From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**list.uvm.edu] On Behalf Of Russell Vernon
Sent: Wednesday, June 29, 2011 5:13 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] FW: Lithium Aluminum Hydride & friction as an ignition source

Dear Chemical Safety Experts,

One of the labs on our campus had a fire when the researcher scraped lithium aluminum hydride (LiAlH₄) out of the glass jar in which it was packaged. The LiAlH₄ was old and the researcher was using a dry metal spatula. A quick review of the manufacturer’s Material Safety Data Sheet informed the user of moisture sensitivity but there is no indication of friction causing a fire.

The supervising faculty member reported personal knowledge that friction can cause ignition of LiAlH₄.

The manufacturer (Sigma-Aldrich) of this material was contacted and responded:

From: Gregory Stachowiak [mailto:Gregory.Stachowiak**At_Symbol_Here**sial.com] On Behalf Of Sigma-Aldrich Technical Service
Sent: Friday, June 24, 2011 8:17 AM
To: Russell Vernon
Cc: Chantalle Carver
Subject: RE: 199877 -- Lithium Aluminum Hydride

Hello again Russell,

We do not have any data on-hand suggesting that friction alone could cause ignition, however, all of our handling of this chemical is performed inside a glove bag under a completely inert atmosphere (argon specifically). This inert atmosphere, combined with the idea that we don't "spread the product out over a large, flat, combustible surface" is likely why we have never had any issues with fires starting during the packaging process.

As shown by those links, however, such an ignition does appear to be possible. All we can recommend is handling this product under argon in a glove box or a glove bag to minimize the oxygen and moisture contact and therefore minimize the chances of a fire.

Unfortunately , because we have not had issues with this problem, we do not have a specific written procedure for weighing it, no.

Best regards,
Gregory Stachowiak

SIGMA-ALDRICH

Gregory Stachowiak / Scientist, Technical Service Associate
Technical Services
6000 N Teutonia Avenue / Milwaukee WI 53209 / USA
P: (800) 231-8327, x5326 / Gregory.Stachowiak**At_Symbol_Here**sial.com
sigma-aldrich.com

http://cameochemical s.noaa.gov/chemical/989

http://www.chemicalbook.com/ChemicalProductProperty_EN_CB7318252.htm

http:// www.erowid.org/chemicals/dmt/dmt_synthesis1.shtml scroll down to step 3:

http://web.princeton.edu/sites/ehs/labsafetymanual/cheminfo/lah.htm

So it appears likely that friction alone in the presence of air may be able to ignite lithium aluminum hydride.

You may want to evaluate your own use and written procedures to prevent this from happening in your world.

Sincerely,

-Russ

Russell Vernon, Ph.D.

Director

Environmental Health & Safety

University of California, Riverside