Transcript Adventures in ‘Real World’ Chemistry

Adventures in ‘Real World’ Chemistry
David M. Manuta, Ph.D., FAIC, President,
Manuta Chemical Consulting, Inc.
Waverly, OH 45690-1208
November 11, 2002 at SUNY Binghamton
Mission Statement:
• The Application of Fundamental Chemical Principles
to Solve Problems.
Vision Statement:
• To Solve Problems That Aren’t in Any Book.
Business Objective:
• Have I Applied My Specialized Knowledge to Help
Others Who Under Other Circumstances Wouldn’t Be
Able to Help Themselves?
Manuta Chemical Consulting, Inc. (MC2) has been
involved in many interesting scientific investigations.
Among these investigations are:
 Chemistry Issues in the Uranium Enrichment Process
 Participating in the Shut Down of a Manufacturing
Plant in Nevada
 Unusual Chemical Reactions in an Aluminum Fire
Typical investigations require the client to allow a
“site visit.” In addition, the advent of the Internet
enables the investigator to bring “the Library” home.
Some valuable reference volumes are:
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CRC Handbook of Chemistry and Physics
Chemical Engineering for Chemists by Griskey
College Physics by Serway and Faughn
General Chemistry by Brady
Organic Chemistry by Solomons
Physical Science by Shipman, Adams, and Wilson
Some Chemical Reactions in Uranium Enrichment
UF6(g) + 2 H2O(g)  UO2F2(s) + 4 HF(g)
(1)
 UF6 is uranium hexafluoride, an easily sublimed solid,
and UO2F2 is uranyl fluoride, a high melting point
solid.
The designations (g) and (s) are for gas and solid,
respectively.
UO2F2(s) + 2 ClF3(g)  UF6(g) + ClF(g) + ClO2F(g) (2)
 ClF3 is chlorine trifluoride, ClF is chlorine
monofluoride and ClO2F is chloryl fluoride.
 This disproportionation reaction is used to recover
uranium hexafluoride from solid uranium deposits,
primarily as uranyl fluoride, from the process piping.
 Fluorine chemistry is important in uranium
enrichment and in the recovery of uranium
hexafluoride.
 In-leakage of water vapor into the below atmospheric
pressure uranium enrichment gaseous diffusion
cascades is responsible for the chemical reaction
producing uranyl fluoride and hydrogen fluoride.
 The thermodynamics pertaining to hydrogen fluoride
formation are favorable in uranium enrichment
gaseous diffusion cascades.
 When the ratio of water to uranium hexafluoride is
less than 2:1, other intermediate uranium oxofluoride
compounds (U-O-F) are formed.
 This work was presented in two papers at the A.C.S.
National Meeting in Chicago, IL in 1995.
 Hydrogen fluoride is considered to be ubiquitous in
gaseous diffusion cascades and an infrared method
has been devised to detect and quantify it.
 This work was presented in a paper at the A.C.S.
National Meeting in San Francisco, CA in 1997.
Shutting a Plant Down in Nevada
 Advanced Specialty Gas (ASG) facility in Dayton, NV
was a manufacturer of nitrogen trifluoride (NF3).
 This gas has been used as a rocket propellant and
has an application in the manufacture of circuit
boards.
 With the phase out of sulfur hexafluoride (SF6), due
to greenhouse gas and global warming issues, the
demand for NF3 has grown in recent years.
 ASG obtained a special use permit from the Lyon
County (NV) Board of Commissioners to manufacture
NF3. The special use permit enabled ASG to keep
ammonia (NH3) and hydrogen fluoride (HF) on site.
The balanced chemical reaction to produce NF3 is:
NH3(g) + 3 HF(g)  NF3(g) + 3 H2(g) (3)
 The special use permit indicated the amounts of NH3
and HF that Lyon County would allow ASG to store
on-site.
In my investigation, among other findings:
 I was surprised to learn that ASG was allowed to
keep more NH3 on-site than HF.
 The HF became the limiting reagent in the NF3
manufacturing process.
 I was also surprised to learn that the H2 was vented
out a smoke stack. No attempt, to the best of my
knowledge, was made to recover it.
 ASG had three releases to the environment and one
explosion which blew the roof off of their lab between
1997 and 2000. The explosion also started a brush
fire in the immediate area of the plant.
 It was after the explosion and brush fire that my
expert services were requested.
 The owner of the real estate contiguous to the plant
recognized that he would be unable to sub-divide his
land for residential housing as long as the ASG plant
continued to operate in Dayton, NV. I was retained,
primarily, to protect this man’s investment.
 Lyon County had previously hired experts who did
not have experience in fluorine chemistry. As a
result, little progress had been made regarding ASG.
 I testified before the Lyon County commissioners in
their chambers and I was specific in identifying the
unsafe practices at the facility.
 The Lyon County commissioners one week later
voted 3-2 to revoke ASG’s special use permit. This
action effectively shut the ASG facility down.
 Copies of my technical report plus articles from the
Carson City and Reno newspapers are available.
The Chemistry of an Industrial Aluminum Fire
 In December 1998, there was a fire at the
Portsmouth Gaseous Diffusion Plant in Piketon, OH.
 I was tasked by senior plant management to
determine the cause and origin of the fire.
 I also was tasked with supervising the on-site
laboratory studies of gaseous and solid samples
brought out of the damaged process equipment.
Unusual chemical reactions in the fire
2 Al(s) + 3 UF6(g)  2 AlF3(s) + 3 UF4 (s)
(4)
 AlF3 is aluminum fluoride
 UF4 is uranium tetrafluoride
2 Al(s) + 6 HF(g)  2 AlF3(s) + 3 H2(g)
(5)
 These two reactions apparently started the fire.
 Rotating equipment made out of aluminum started to
melt and the molten aluminum then reacted with the
available fluorine-bearing compounds to produce
aluminum fluoride and considerable amounts of heat.
2 Al(s) + 3 UO2F2(s)  2 AlF3(s) + 3 UO2(s)
(6)
14 Al(s) + 3 C2F4Cl2(g) 
4 AlF3(s) + Al2Cl6(g) + 2 Al4C3(s)
(7)
 Additional chemical reactions producing aluminum
fluoride took place, culminating in the catastrophic
loss of coolant (R-114 is C2F4Cl2).
 The coolant was actually consumed in the fire.
 Al2Cl6 is aluminum chloride
 Al4C3 is aluminum carbide.
 The series of chemical reactions producing aluminum
fluoride effectively created the “fluorine-analog” of the
Thermite reaction.
 In order to generate aluminum carbide, temperatures
in excess of 2000°C (3632°F) in a hydrogen-rich or a
reducing atmosphere were necessary.
 If the intense thermal conditions and/or the hydrogen
were not available to the molten aluminum, the
carbon present in the R-114 was found to have
deposited in the process piping as a “sooty residue.”
 In the fluorine-rich environment which existed in the
process piping, both the aluminum carbide and the
aluminum chloride were converted to aluminum
fluoride.
 The aluminum carbide was identified in regions of the
process piping where little exposure to fluorinated
material existed.
 Many of these chemical reactions and the conditions
necessary for them to take place were cited in: The
Chemist, March/April 2000, pp. 21-24.
 When the process piping, was opened, the solid had
burst into flames. The relevant reaction is:
Al4C3(s) + 6 H2O(g)  2 Al2O3(s) + 3 CH4(g)
(8)
 The formation of aluminum oxide (Al2O3) generates
so much heat that the methane (CH4) produced burst
into flames; its flash point had been exceeded.
 When the flashing of the methane was observed, I
was tasked with determining what had happened.
 Brady’s General Chemistry text has a section on
aluminum carbide.
14 Al(s) + 3 C2F4Cl2(g) 
4 AlF3(s) + Al2Cl6(g) + 2 Al4C3(s)
(7)
 Equation (7) summarizes the catastrophic reaction of
the molten aluminum with the R-114 coolant.
 This balanced redox reaction requires a transfer of 18
electrons!
 The thermodynamics associated with equation (7)
and several other chemical reactions in the fire were
cited in: The Chemist, September/October 2000, pp.
19-24.
On-going work
 Exposure to the allegedly hazardous ingredient in a
commercial product. This southeastern KY legal
case has demonstrated how little chemistry the
attorneys for a multi-national company actually know.
 A group of insurance companies have paid for
property damage resulting from the explosion of a
fireworks magazine in western PA. My task has been
to apply the chemistry and physics to determine the
radius of the “circle of causation.” This is to compel
the owner of the magazine to reimburse the insurers
for the damage that was caused by the explosion.
 Industrial troubleshooting at the Paducah Gaseous
Diffusion Plant in western KY.
 Several legal cases are in development regarding
occupational exposure and laboratory methodology
throughout this country.