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The use of Anhydrous Ammonia


#1

As a fire inspector, I am curious as to why a small jewelry
manufacturer would have Anhydrous Ammonia tanks. I understand the
oxygen for welding and molding purposes, but don’t know why the
Anhydrous Ammonia would be there. Any suggestions?

Laura Single
Bergen County Law & Public Safety Institute


#2

The anhydrous ammonia is run through a “cracker” or dis-associator
to be broken down into hydrogen and nitrogen by heat. The resulting
gasses are fed into a kiln or furnace to provide a strongly reducing
atmosphere (no oxygen present). This allows for bright annealing and
kiln soldering operations of a high quality.

Jim


#3
    As a fire inspector, I am curious as to why a small jewelry
manufacturer would have Anhydrous Ammonia tanks.  I understand the
oxygen for welding and molding purposes, but don't know why the
Anhydrous Ammonia would be there.  Any suggestions? 

The first (only right now) thing I can think of is as a feed for an
ammonia dissociater to make a reducing atmosphere for a brazing-
annealing furnace. This would be a belt furnace which will be a
heated box with a belt running through it. The gas 75% Hydogen 25%
Nitrogen will provide a reducing atmosphere in the furnace. The gas
escaping from the furnace is burned off at each end. The gas is
flammable and can be explosive if not handled correctly.

Jesse


#4
   As a fire inspector, I am curious as to why a small jewelry
manufacturer would have Anhydrous Ammonia tanks.  I understand the
oxygen for welding and molding purposes, but don't know why the
Anhydrous Ammonia would be there.  Any suggestions? 

Not sure if this is quite something a SMALL manufacturer would use,
but some types of annealing, melting, soldering, or heat treating
furnaces use a controlled atmosphere to prevent oxidation. One very
common way to do this is to “crack” ammonia into hydrogen and
nitrogen. The nitrogen/hydrogen gas mix is then fed to the furnace
where the hydrogen scavenges any oxygen present, leaving the metal
clean. Most smaller machines do this, however, with welding tank
size tanks of what’s usually labeled “forming gas”, which is the
same mix, I think. Ammonia has other uses, as a degreaser, etc, but
that usually doesn’t require anything as nasty as anhydrous ammonia.
It might have uses in refining, especially refining silver (solvent
for silver chloride) but again, this isn’t common to most smaller
jewelery manufacturers.

My suggesting is to ask them what they use it for. This isn’t such
gentle stuff to have just sitting around unless it’s needed. I
understand your concern…

Peter Rowe


#5
As a fire inspector, I am curious as to why a small jewelry
manufacturer would have Anhydrous Ammonia tanks.  I understand the
oxygen for welding and molding purposes, but don't know why the
Anhydrous Ammonia would be there.  Any suggestions? 

The Anhydrous Ammonia would be used for a Hydrogen Oven. There are
small units that could be used by small jewelry manufacturers. The
most important thing is that the tanks are stored OUTSIDE. If a leak
were to occur the gas can cause very serious injury and death.

As far as the oven is concerned if it is in good working order there
should not be any problems. If the oven doesn’t work it would be wise
for the company to get rid of the Anhydrous Ammonia until they can
get the oven back in working order.

If they don’t have a Hydrogen Oven they should get rid of the
Anhydrous Ammonia unless they have another use for it. But again the
tank should be outside and not near any exits.

As has been stated. If the oven is not in proper working order it can
be very dangerous.

Ken Kotoski
MPG Repair
www.mpgrepair.com
1-877-262-2185


#6

Howdy laura, Others here can give more detail, but ‘cracking’ ammonia
into nitrogen and hydrogen is done by some folks who refine (and
cast?) precious metals. It helps to remove oxides from the molten
alloy/metal. Electronics manufacturers sometimes use the nitrogen
component to protect solder paste from oxidizing during reflow.

Carl
1 Lucky Texan


#7

Anhydrous ammonia is just that, a nasty, choking, toxic, water
hungry, blistering gas, lighter than air and very dangerous to have
about when it isn’t really necessary. It does consist of nitrogen
and hydrogen, is NH3, whereas the liquid ammonia available in
supermarkets is a dilute solution in water of the gas: NH4OH, and
nothing like as dangerous.

Now any company specializing in bottled gases will sell a cylinder
of what they call ‘forming gas’, which is a mixture of 75% hydrogen
and 25% nitrogen gases, and apart from the fact that it is
flammable and explosive with air, much like any gas used in a
torch, it isn’t at all poisonous, and no more dangerous than torch
gases.

The forming gas is used in enclosed electrically heated furnaces to
make an oxygen free, reducing atmosphere . Such furnaces have
tungsten or molybdenum heating elements so they can be heated to
2000C, or they can be induction furnaces, using a very high
frequency magnetic field to produce an extremely high current in the
metal to heat it…

So I really cannot understand why any industrialist would in these
times, use anhydrous ammonia and crack it in a separate furnace;
instead of using far less harmful, cheap, forming gas, which gives
the same results. The only other industrial use (I can think of) for
anhydrous ammonia is in very large refrigerating plants.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#8
   As a fire inspector, I am curious as to why a small jewelry
manufacturer would have Anhydrous Ammonia tanks.  I understand the
oxygen for welding and molding purposes, but don't know why the
Anhydrous Ammonia would be there.  Any suggestions?  

Hi Laura, I can think of one -very- common use for Anhydrous Ammonia.
(There may well be others.) The best compound I’ve ever tested for
cleaning jewelry is prepared from an equal mixture of one part
Ammonia, one part strong liquid detergent, and one part Isopropanol.
(This solution should never be used on pieces which contain porous,
fragile or organic gems.)

Hope this sheds some light on your question… :slight_smile:

Peter


#9

Hi John,

The only other industrial use (I can think of) for anhydrous
ammonia is in very large refrigerating plants.

While it isn’t exactly an ‘industrial application’, each spring
thousands of tons (maybe millions) of anhydrous ammonia is made &
used by the agricultural community in the Midwestern US. It’s
applied to the fields with a toothed plow as a fertilizer. Makes the
crops grow like crazy.

Now, armed with that bit of info, isn’t it easier to make a piece of
jewelry? (bg).

Dave


#10
So I really cannot understand why any industrialist would in these
times, use anhydrous ammonia and crack it in a separate furnace;
instead of using far less harmful, cheap, forming gas, which gives
the same results. The only other industrial use (I can think of) 
for anhydrous ammonia is in very large refrigerating plants. 

Dear Mr. Burgess, Anhydrous Ammonia is used for many things that
benefit us every day. Here are a few.

Neutralizing sulfuric acid in the production of paraminophenol (used
in the production of acetaminophen) (aspirin), Manufacture of plastics
and intermediates, Metal processing, Etching gas in semiconductor
manufacturing Mixed with silane to make silicon nitride, Production of
hexamine for explosives (road building of course), Raw material in
the textile industry, Acid production, dyes, insecticides,
Fertilizers, Synthetic resins, Catalytic agent in manufacturing
processes, And finally a Refrigerant

For the jewelry industry, the cracking of anhydrous ammonia is
typically used in belt drive soldering furnaces where companies are
assembling metal parts on a larger scale. The hydrogen that is
generated by the decomposition of the NH3 prevents oxidation of the
parts being assembled. It is a production tool. This decomposition
reaction only occurs at high temperature so the ovens must be very
hot for it to work and the amount of available oxygen is tiny. The
small hydrogen flames that are seen eminating from the entrance and
exit of soldering furnaces prevent oxygen from entering the heating
(work) zone. Some oxides that might already exist on the parts
traveling through the work zone of the oven will be reduced back to
metallics.

Mixtures of Hydrogen and Nitrogen, with a Hydrogen ratio higher than
about 10% can be explosive. Forming gas (25% H2 + 75%N2) can exist
at room temperature, can pocket under certain conditions, and can
explode with a spark without you ever having a clue that there was a
leak. Don’t get me wrong, in certain applications, I also like and
do use forming gas. I have a gas blender and mix my own ratios
depending. There are always pluses and minuses to nearly all of our
tools. One bad thing about forming gas is that you can’t smell it.
It will sneak up on you and then blow you to kingdom come. In the
wrong hands or used improperly, anhydrous ammonia can definately kill
you. At least you will know you have a leak before it does.

We have chosen to live and work in the jewelry business. We should
only work with tools and chemicals that we are trained to use and are
comfortable with. If anyone of us is asked to use a machine or
chemical that we are not trained to use and are not comfortable with,
get training or stay away from it. While it is always good to
question, learn, and even be skeptical, it is best not to dismiss or
condemn those that are trained.

Something my father always told me that kind of sums it up, (a
southern thing), “I drink 8 glasses of water a day for my health but
you can drown in an inch of it if your face down in it.”

Best intentions,
J. Tyler Teague
JETT Research
(Jewelry Engineering, Training, & Technology)


#11

While it isn’t exactly an ‘industrial application’, each spring
thousands of tons (maybe millions) of anhydrous ammonia is made &
used by the agricultural community in the Midwestern US. It’s
applied to the fields with a toothed plow as a fertilizer. Makes the
crops grow like crazy.

G’day The word anhydrous means literally ‘without water’ , and
anhydrous substances, no matter what, are not only dry but contain
no water of crystallisation. Thus crystals of sodium bisulphate
for instance, which is used as a pickle, can be dry, even though it
contains water of crystallization NaHSO4.10 H20 but anhydrous
sodium bisulphate is simply NaHSO4, a completely dry white powder
with no water molecule attached at all.

Thus anhydrous ammonia is simply NH3, or properly, nitrogen
tri-hydride, and is a deadly choking, blistering poisonous gas you
don’t want to have anything to do with.

I certainly cannot imagine farmers pumping the gas, anhydrous
ammonia over their ground - they would have to wear a gas mask and
an anti gas suit to do it, or choke to death. May I suggest that
what they plough into their ground is an ammonium salt, like
ammonium sulphate or ammonium nitrate almost invariably in a water
solution. But never, never, never, anhydrous ammonia!! It might
sterilize the ground, but what would it do to the farmer? But I still
don’t know what a modern jewellery company would do with it.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ


#12
    I certainly cannot imagine farmers pumping the gas, anhydrous
ammonia over their ground - they would have to wear a gas mask and
an anti gas suit to do it, or choke to death.   May I suggest that
what they plough into their ground is an ammonium salt, like
ammonium sulphate or ammonium nitrate almost invariably in a water
solution.   But never, never, never, anhydrous ammonia!! It might
sterilize the ground, but what would it do to the farmer? 

–John, Go to a seach engine and type in Iowa
farming/fertilizer/anhydrous ammonia and you will find an
explanation. What ever they use, I know they call it anhydrous
ammonia. Maybe it’s in another form and I don’t understand it either
but maybe someone can help us understand this
further??? Annette in Iowa with a corn field in my back yard.


#13
  I certainly cannot imagine farmers pumping the gas, anhydrous
ammonia over their ground - they would have to wear a gas mask and
an anti gas suit to do it, or choke to death.   May I suggest that
what they plough into their ground is an ammonium salt, like
ammonium sulphate or ammonium nitrate almost invariably in a water
solution.   But never, never, never, anhydrous ammonia!! It might
sterilize the ground, but what would it do to the farmer? But I
still don't know what a modern jewellery company would do with it. 

I’m not so sure, John,exactly how the stuff is put into the fields.
Out here in the Idaho wheat country I see the farm supply places with
huge tanks of ammonia. Not as a liquid, but in cylinders like
propane would be transported in. Concerning the applicators that
are pulled out into the field, and I thought they had that kind of a
tank also and it was drilled into the soil This is dry land farming.
However, when my father raised sprinkler irrigated crops, he bubbled
the ammonia through water and then piped the resulting mix
directly into the water running through the sprinkler pipes. Rose
Alene McArthur


#14

Hi John,

I certainly cannot imagine farmers pumping the gas, anhydrous
ammonia over their ground - they would have to wear a gas mask and
an anti gas suit to do it, or choke to death.   May I suggest that
what they plough into their ground is an ammonium salt, like
ammonium sulphate or ammonium nitrate almost invariably in a water
solution. 

You may be correct! However, the stuff used by farmers in the
Midwestern US is “called” anhydrous ammonia & is a liquid.
Depending on location, it’s shipped in aprox 10,000 gallon tank
trucks from the mfg plant directly to the end user. The safety
restrictions around it’s mfg, transportation & use are strict.

Like everything else that’s sold in this world, the name may be a
figment of some advertising execs imagination, with just a little
bit of truth.

Dave


#15
   --John, Go to a seach engine and type in Iowa
farming/fertilizer/anhydrous ammonia and you will find an
explanation. What ever they use, I know they call it anhydrous
ammonia. Maybe it's in another form and I don't understand it
either but maybe someone can help us understand this further??? 

Following your links, Annette, (eliminating the word Iowa, and just
searching for “+farming+anhydrous ammonia” in google did indeed find,
amonst the hits, the explanation. It really is true anhydrous
ammonia, stored in tanks under pressure suffient for it to be a
liquid (much the way butane or propane are liquid at higher
pressures, but a gas at normal atmospheric pressure). The pressure
depends on temperature, varying from under 100 psi to over 200 psi,
so the tanks need to be capable of that. The stuff is used by
injecting it the liquid anhydrous ammonia 6 to 8 inches below the
soil surface. The liquid injected quickly turns to gas, but being
that far under the surface, doesn’t escape before becoming dissolved
in soil moisture, thus essentially producing an ammonia solution in
water distributed in the soil. Apparently this is a great fertilizer
for some needs, and from the hits I read, appears to be in wide use.
A number of hits were councelling farmers in how to secure their
tanks against theft, since it also appears the stuff is popular with
those people who use it to make methamphetamenes illegally…

Peter


#16

It really is anhydrous ammonia. It is stored and transported under
pressure as a liquid. The physical properties are similar to
propane and the same transport trucks are used for both. The gas is
injected just below the surface as the soil is tilled. Adsorption is
almost instantaneous and complete. No gas mask or suit. This
system is very widely used growing corn (maize) and cotton etc…

Jesse


#17

Hello Dave and Orchidland, Dave is correct:

    However, the stuff used by farmers in the Midwestern US is
"called" anhydrous ammonia & is a liquid. 

The fertilizer is indeed anhydrous ammonia and is taken from the
bottom of the tank as a liquid. The liquid is dispensed into the
ground via a small tube mounted behind the steel claw-like points on
the implement pulled behind the tractor. If you see this operation
in the field, you will see the tank trailing the implement to which
it is connected by hoses. The liquid does indeed change to a gas
upon release, but is trapped by the soil falling back in on top of
the deep furrow made by the “chisel” point. Soil moisture reacts
with the ammonia and holds it underground for bacterial action and
ultimate availability as nitrogen for plant uptake.

There.  That's more than you wanted to know!  BTW, nitrogen is also

applied as a liquid in the form of urea. It is considered more
"farmer- friendly" - fewer safety issues.

Judy in Kansas, where it's going to be a lovely spring day with

more to follow. Forsythia is in full bloom. Redbuds are swelling
and when they come out, the hills will be accented with drifts of
pink.

Judy M. Willingham, R.S.
Biological and Agricultural Engineering
237 Seaton Hall
Kansas State University
Manhattan KS 66506
(785) 532-2936


#18
"called" anhydrous ammonia & ...Like everything else that's sold
in this world, the name may be a figment of some advertising execs
imagination, with just a little bit of truth. 

Many years ago I was employed as a Chemical engineer in the
Anhydrous Ammonia business. The Anhydrous Ammonia used by farmers is
definitely virtually pure anhydrous ammonia NH3. It is shipped
under pressure and applied by farmers just below the soil surface.
Some portion escapes to the atmosphere as ammonia gas and the rest
is bound up with moisture in the soil. It is a very effective and
economical way for farmers to apply nitrogen fertilizer.

Anhydrous ammonia is also used to make the ammonium salts (ammonium
sulphate and ammonium nitrate) that John referred to.

Interesting how we went from discussing jewellery to discussing
farming.

Regards
Milt Fischbein
Calgary, Canada


#19

It is however, VERY hard on ANY soil life be it insect, plant,
fungus, bacteria, nematode, worm, etc. Basically gives a sterile
area where it is injected. Liquid ammonia is also used in large
commercial refrigeration units as the heat exchange gas (replaced
with fluorine gasses in smaller units and in home appliances).
Special OBA’s (Oxygen Breathing Apparatus - units that make oxygen
in an internal gas loop, these do not “filter” air as in normal
mask filter units) are required to be available in the areas of the
refrigeration units and when handling the Ag materials.

Be careful with it…

Again, more than anyone wanted to know…

JD