A university researcher reported that a fire resulted when he scraped lithium aluminum hydride (LiAlH4) out of the glass jar in which it was contained (see attached photo). The jar had been in the laboratory since 2005 (about 6 years), so the LiAlH4 was old. The researcher was using a dry metal spatula to scrape the LiAlH4 out of the jar. A quick review of the manufacturer's Material Safety Data Sheet (MSDS) for LiAlH4 informed the researcher of its moisture sensitivity, but there was no indication of friction causing a fire. However, the supervising faculty member reported personal knowledge that friction can cause ignition of LiAlH4.
The fire was put out with an ABC extinguisher. In the attached photo, the ABC extinguishing agent is the yellow powder.
As stated on the MSDS and also on the container labels, LiAlH4 should be handled under argon. LiAlH4 is advertised and sold as a powder. If the researcher had to scrape it out of the jar, then it was no longer a powder, which seems indicative of past reaction that may have been due to exposure to atmospheric moisture.
The manufacturer stated that they do not have any first-hand data suggesting that friction alone could cause ignition. All of their handling of LiAlH4 is performed inside a glove bag under an argon atmosphere, so they have never had a fire during the packaging process. They recommend handling LiAlH4 under argon in a glove box or glove bag to minimize oxygen and moisture contact and, therefore, minimize the chance of a fire.
The university ES&H department did some searching online and found several relevant websites that provide confirmation that friction alone in the presence of air may be able to ignite LiAlH4.
http://cameochemicals.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
Since the university has adopted the following standard operating procedures, there has not been a reoccurrence of this type of incident:
- Only non-metal spatulas are to be used with metal hydrides.
- All work with metal hydrides must be done under an inert gas atmosphere (either argon or nitrogen).