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Date: Tue, 6 Jul 2010 15:20:18 -0400
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Kim Auletta <kauletta**At_Symbol_Here**NOTES.CC.SUNYSB.EDU>
Subject: Re: Sol-gel drying process
In-Reply-To: <F5D83326DC77FD4EA138E9194D6B2888337233F7EE**At_Symbol_Here**DSMAILBOX.ad.uiuc.edu>
Its important to know if the oven is rated for flammable solvent/vapors.
In another life I inspected a facility that used methanol as a binder in
an oven that was not rated for flammables. The large door ended up across
the room & the yellow powder was everywhere.
Kim Auletta
Lab Safety Specialist
EH&S Z=6200
Stony Brook University
kauletta**At_Symbol_Here**notes.cc.sunysb.edu
631-632-3032
EH&S Web site: http://www.stonybrook.edu/ehs/lab/
Remember to wash your hands!
From:
"Tsiakals, Nicholas John"
To:
DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Date:
07/06/2010 03:16 PM
Subject:
Re: [DCHAS-L] Sol-gel drying process
Sent by:
DCHAS-L Discussion List
CanÕt say IÕm familiar with the chemistry. Even so, I would turn these
questions back at the lab(s) involved:
What were the intermediates/byproducts produced?
What was being evaporated at the hood? At the oven?
I question the hot plate boil-off and the convection oven for solvent.
(If flammable atmospheres, then intrinsically safe electrical components
required.)
(Did the convection oven vent to the room?)
Solvent/vapor recovery would be more robust Ð required at larger scale.
Does the person involved appreciate:
Consequences were limited in this case by unwitting accidents of scale and
access.
I realize this is unrefined, but this is where I would start with the
ideas/questions.
-Nick
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of
Perry Cooper
Sent: Tuesday, July 06, 2010 11:04 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Sol-gel drying process
Sharing an incident. Anyone want to chip in on recommendations? J
General lab exhaust through the fume hood. Some equipment exhausted with
localized flex duct but not the oven.
Adjacent areas complained of strong alcohol odor.
"É.. intent to prepare a batch of fine particulate size aluminum oxide via
the sol gel process. The components were an organometallic (aluminum sec-
butoxide), a solvent (2-propanol) and water. 1.5l of 2-propanol was
placed in a porcelain-lined steel container. 4.5kg of aluminum
sec-butoxide was added to the solvent while mixing. After these components
were thoroughly mixed, 1.1l of water was added resulting in the formation
of AlOH particles from the organic precursor. At this point, the
composition was a viscous slurry. In order to reduce the solvent content,
the container was placed on a hot plate inside the fume hood. The
composition was heated (temperature unknown but estimated to be 70-80¡C)
for approximately 4 hours. At the end of this period, most of the solvent
had evaporated, leaving a slightly moist "cake". In order to remove the
remaining solvent, the container was taken to room xxxxx and placed in a
convection oven. I partially covered the container with a lid to allow
venting and to prevent any swirling debris from contaminating the
material. Oven temperature was set at 130¡C and the general exhaust in
this room was turned on. My intent was to let the material dry overnight
and I left for the day. When I returned the following day, I checked the
oven and it was apparent that there had been an accident at some point
after I left. I later learned that there had been a small explosion and
fire. I believe the fire was confined to the oven and was extinguished by
covering the container with the lid. The oven door was bent when it swung
open and contacted the control enclosure but no other damage is apparent.
In the past, I have used these same procedures and equipment to make
similar compositions without incidentÉ."
Regards,
Perry
_______________________________
Perry D. Cooper, MS, HEM, CCHO
Manager - HSE - JHU
The Johns Hopkins University
Health, Safety & Environment
www.hopkinsmedicine.org/hse
Homewood Campus Safety Office
3400 N. Charles Street
G04 Wyman Park Bldg
Baltimore, MD 21218
Office: 410-516-2345
Fax: 410-516-4314
www.jhu.edu/safety
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