extinguishing thermite
Michael Michalchik
> N2 would explode due to strong dilatation (from -190°C to 3000°C).
> Never use water! but in very very large amount...tiny amounts will
> propagate the burning mix in all directions with tiny explosions!
> Carbon would be of no use since Al is much more electropositive than it,
Though this is true, remember Le Chattliers principle, if the carbon
gets to the oxygen first the oxygen will be gone in the form of carbon
dioxide before the aluminum has a chance to get to it. I suggested on
a couple of the other groups that a low viscosity dispersion of
graphite in a low carbon silicone oil might work because the oil would
seperate the particals and allow the graphite to penetrate the
mixture, the graphite would consume oxygen without the production of
much heat, CO2 would carry heat away from the reaction as would the
decomposition and combustion of the silicone oil. All this might lower
the temp enough and seperate the particals enough to interupt the
reaction.
So if I wind up giving this demo to the fire department, what do you
guys suggest I talk to them about?
I am currently planning:
Places where thermite mixtures might be found.
What their legitimate and illegitimate uses are.
The basic chemistry and properties of the reaction.
How it can be made.
The big don'ts with regard to thermite.
How to cope with it.
The ways that it could be augmented by a terrorist to make it very
nasty.
The demonstrations I may include are:
The basic reaction
What pre-compression does to rate of reaction.
What happens when you leave a penny inside a pile of thermite
What happens when you leave a cup of water on top of a pile of
thermite
John Gilmer
>
> Though this is true, remember Le Chattliers principle, if the carbon
> gets to the oxygen first the oxygen will be gone in the form of carbon
> dioxide before the aluminum has a chance to get to it. I suggested on
> a couple of the other groups that a low viscosity dispersion of
> graphite in a low carbon silicone oil might work because the oil would
> seperate the particals and allow the graphite to penetrate the
> mixture, the graphite would consume oxygen without the production of
> much heat, CO2 would carry heat away from the reaction as would the
> decomposition and combustion of the silicone oil.
OK. IF you want to get carbon at the reaction site to beat the Al to the
Oxygen they why screw around with silicone oil?
Just dump some regular oil on the thermite. You convert the thermite fire
into a oil fire. The advantage is that we know how to put out an oil fire!
rsymes
Michael Michalchik wrote:
> I am currently planning:
> Places where thermite mixtures might be found.
> What their legitimate and illegitimate uses are.
> The basic chemistry and properties of the reaction.
> How it can be made.
> The big don'ts with regard to thermite.
> How to cope with it.
> The ways that it could be augmented by a terrorist to make it very
> nasty.
>
> The demonstrations I may include are:
>
> The basic reaction
> What pre-compression does to rate of reaction.
> What happens when you leave a penny inside a pile of thermite
> What happens when you leave a cup of water on top of a pile of
> thermite
You planning on trying metals oxides other than iron? I've tried titanium oxide with
mixed results. What about ignition methods? I've used Pot. permanganate and glycerine
as a delayed ignition source although its a tad unpredictable.
I'm not sure "The ways that it could be augmented by a terrorist to make it very
nasty" will be too popular with some people. Its nasty ennough already.
Feral Chemist
Terry Wilder
problems at Chernobyl?
"John Gilmer" <gil...@crosslink.net> wrote in message
news:3d49f0e4$0$22...@dingus.crosslink.net...
Dale A Trynor
> LOUIS <Loui...@SKYNET.be> wrote in message news:<3D46F493...@SKYNET.be>...
> > N2 would explode due to strong dilatation (from -190°C to 3000°C).
> > Never use water! but in very very large amount...tiny amounts will
> > propagate the burning mix in all directions with tiny explosions!
> > Carbon would be of no use since Al is much more electropositive than it,
>
> Though this is true, remember Le Chattliers principle, if the carbon
> gets to the oxygen first the oxygen will be gone in the form of carbon
> dioxide before the aluminum has a chance to get to it. I suggested on
> a couple of the other groups that a low viscosity dispersion of
> graphite in a low carbon silicone oil might work because the oil would
> seperate the particals and allow the graphite to penetrate the
> mixture, the graphite would consume oxygen without the production of
> much heat, CO2 would carry heat away from the reaction as would the
> decomposition and combustion of the silicone oil. All this might lower
> the temp enough and seperate the particals enough to interupt the
> reaction.
Dale Trynor wrote:
What about something like ordinary salt because we are talking about such high
temperatures it may work just like water and its evaporation will not result in
combustion. I would imagine that its evaporation would cool I don't know how well its
effect would be.
Zinc chloride might be worth experimenting with as it has a very low melting point
and or with its advantage of oil or resin solubility, as used in plumbers flux.
What might be most ideal would be some type of high temperature breakdown products
such as produced from heating of thorium or magnesium nitrate, that would produce
thorium or magnesium oxide. Something with this kind of an extremely high melting
point might coat the particles inhibiting the termite reaction.
Just using some quick impulsive guessing and note I said _guessing_, but something
along the lines of a 2 part liquid and or low melting point solids mix of something
such as zinc chloride and methyl boron,( spelling? ) "I am trying to remember the
one made by dissolving boric oxide in methyl alcohol". Could be of the sort of thing
worth experimenting with, assuming that a zinc borate, could be made to quickly form
and would have a high melting point etc.
If I spent some time I could probably come up with hundreds of possible experiments
of this sort and most, such as the suggestion above, would not work. I was just
starting to get some ideas about using titanium tetrachloride as it will rapidly form
an oxide and is used in sky writing for this reason but what else would the other
component be besides ammonium hydroxide, maybe an organic.
>
>
> So if I wind up giving this demo to the fire department, what do you
> guys suggest I talk to them about?
>
> I am currently planning:
> Places where thermite mixtures might be found.
> What their legitimate and illegitimate uses are.
Welding rebar in construction use for one.
>
> The basic chemistry and properties of the reaction.
> How it can be made.
> The big don'ts with regard to thermite.
> How to cope with it.
> The ways that it could be augmented by a terrorist to make it very
> nasty.
Add mercury its salts, or other toxics that evaporate.
>
>
> The demonstrations I may include are:
>
> The basic reaction
> What pre-compression does to rate of reaction.
> What happens when you leave a penny inside a pile of thermite
> What happens when you leave a cup of water on top of a pile of
> thermite
Don't forget other types of mixes such as copper oxide with aluminum. I don't know if
other metals than aluminum will work but if one could get a termite reaction where
the byproducts have higher boiling points you should have something quite impressive.
Aluminum oxide boils at a little above 2000 C so it cant get much hotter. Underwater
where you have pressure would enable much higher temperatures as the boiling points
are increased.
I remember seeing photos of a type of rod that I believe was termite based that was
used to cut through concrete or some thing similar, wish I could remember the details
for you.
www.alternatescience.com
Dirk Bruere
"Michael Michalchik" <micha...@aol.com> wrote in message
news:20f4bb84.0208...@posting.google.com...
> The demonstrations I may include are:
>
> The basic reaction
> What pre-compression does to rate of reaction.
> What happens when you leave a penny inside a pile of thermite
> What happens when you leave a cup of water on top of a pile of
> thermite
Actually not much at all happens unless you light the thermite. Your
audience might get pretty bored.
How about using MnO2 instead of FeOxide? Any idea what will happen?
Dirk
Dirk Bruere
"Dale A Trynor" <da...@nbnet.nb.ca> wrote in message
news:3D4A6979...@nbnet.nb.ca...
> Michael Michalchik wrote:
> such as zinc chloride and methyl boron,( spelling? ) "I am trying to
remember the
> one made by dissolving boric oxide in methyl alcohol". Could be of the
sort of thing
Does BO dissolve in meth?
Dirk
Mike Swisher
by much. Cr2O3 (which may be made by burning ammonium dichromate) also makes a
thermite. You can increase the yield of manganese from the former reaction by
adding a little potassium permanganate to the MnO2/Al mixture, or of chromium
from the latter by adding a little potassium dichromate to the Cr2O3/Al mixture.
Generally, the lower the heat of formation of the metal oxide used, the more
violent will be the reaction. Copper oxide with fine aluminum is practically a
flash powder. Lead and bismuth oxides are used with magnalium in crackle
compositions, which depend on a very rapid and violent thermite-type reaction.
Ellern presents a good discussion in Military & Civilian Pyrotechnics, pp.
244-250.
In article <aie7oj$14289r$1...@ID-120108.news.dfncis.de>, "Dirk says...
Dirk Bruere
"Mike Swisher" <Mike_...@newsguy.com> wrote in message
news:aie9s...@drn.newsguy.com...
> The reaction using MnO2 will be a bit more violent than with iron oxide,
but not
> by much. Cr2O3 (which may be made by burning ammonium dichromate) also
makes a
> thermite. You can increase the yield of manganese from the former reaction
by
> adding a little potassium permanganate to the MnO2/Al mixture, or of
chromium
> from the latter by adding a little potassium dichromate to the Cr2O3/Al
mixture.
>
> Generally, the lower the heat of formation of the metal oxide used, the
more
> violent will be the reaction. Copper oxide with fine aluminum is
practically a
> flash powder. Lead and bismuth oxides are used with magnalium in crackle
> compositions, which depend on a very rapid and violent thermite-type
reaction.
>
> Ellern presents a good discussion in Military & Civilian Pyrotechnics, pp.
> 244-250.
I assume a touch of KClO3 will also liven it up a bit.
Dirk
Mike Poulton
I think he means boric acid. It reacts with methanol to form trimethyl
borate, a volatile liquid which burns green in the vapor phase.
--
Mike Poulton
MTP Technologies
Not only do I speak for my company, I AM my company!
Live free or die!
http://www.indefenseoffreedom.org/
Dirk Bruere
"Mike Poulton" <mpou...@mtptech.com> wrote in message
news:Xns925E8B5FF27F5m...@68.12.19.6...
> On 02 Aug 2002, "Dirk Bruere" <art...@kbnet.co.uk> said:
>
> >
> > "Dale A Trynor" <da...@nbnet.nb.ca> wrote in message
> > news:3D4A6979...@nbnet.nb.ca...
> >> Michael Michalchik wrote:
> >> such as zinc chloride and methyl boron,( spelling? ) "I am trying to
> > remember the
> >> one made by dissolving boric oxide in methyl alcohol". Could be of
> >> the
> > sort of thing
> >
> > Does BO dissolve in meth?
>
> I think he means boric acid. It reacts with methanol to form trimethyl
> borate, a volatile liquid which burns green in the vapor phase.
What's the toxicity like?
Normally methylated metals are pretty dangerous.
Dirk
Graham Cowan
This is a methoxylated non-metal. Still toxic,
but not, I think, any more so than boric acid
and methanol uncombined.
--- Graham Cowan
http://www.eagle.ca/~gcowan/boron_blast.html --
a good way for cars to gain nuclear cachet
Graham Cowan
This is a methoxylated non-metal. Still toxic,
Mike Swisher
used in "thermate"), will certainly speed things up. But it will not increase
yield of the metal produced by the reaction, as adding a permanganate to
manganese dioxide, or adding a dichromate to chromic oxide will do.
Adding metallic nickel to an aluminum/metal oxide mixture will also change its
reaction rate, because the formation of the intermetallic nickel aluminide is
exothermic.
In article <aiebrd$142hs6$1...@ID-120108.news.dfncis.de>, "Dirk says...
Repeating Decimal
Mike_...@newsguy.com wrote on 8/2/02 8:52 AM:
> The reaction using MnO2 will be a bit more violent than with iron oxide, but
> not
> by much. Cr2O3 (which may be made by burning ammonium dichromate) also makes a
> thermite. You can increase the yield of manganese from the former reaction by
> adding a little potassium permanganate to the MnO2/Al mixture, or of chromium
> from the latter by adding a little potassium dichromate to the Cr2O3/Al
> mixture.
>
> Generally, the lower the heat of formation of the metal oxide used, the more
> violent will be the reaction. Copper oxide with fine aluminum is practically a
> flash powder. Lead and bismuth oxides are used with magnalium in crackle
> compositions, which depend on a very rapid and violent thermite-type reaction.
When I was a kid in high school, a chemistry teacher seemed to be on the
verge of kiling me. I mixed up a batch manganese thermite using
stoichiometric proportions. I clearly marked manganese on the container.
Instead of study hall, I worked in the school's chem lab preparing
demonstrations and all that kind of thing. She used it for a demonstration
that fizzled. She came into the lab livid with anger. She knocked stuff
around in a rage. After all these years I remember that. As a sexist aside,
she was stunningly good looking redhead, and a good teacher.
This leaves a question. Do you get the most vigorous reaction between Al and
MnO2 with nonstoichiometry?
Bill
Michael Michalchik
> >
> > gets to the oxygen first the oxygen will be gone in the form of carbon
> > dioxide before the aluminum has a chance to get to it. I suggested on
> > a couple of the other groups that a low viscosity dispersion of
> > graphite in a low carbon silicone oil might work because the oil would
> > seperate the particals and allow the graphite to penetrate the
> > mixture, the graphite would consume oxygen without the production of
> > much heat, CO2 would carry heat away from the reaction as would the
> > decomposition and combustion of the silicone oil.
>
> OK. IF you want to get carbon at the reaction site to beat the Al to the
> Oxygen they why screw around with silicone oil?
Well, because I don't want to just put get carbon to the oxygen.
Dumping a fuel oil on would have problems with causing a bleve. It
would vaporize to quickly, combine with the air and explode. Also,
hysrocarbon oils would add a lot more energy to the reaction. I chose
silcone oil and graphite because they would cool the reaction through
the formation of gaseous contiuents and would carry oxygen away from
the iron without starting another self-sustaining reaction and I would
hope that they would be high-boiling and low energy enough to prevent
a bleve/fuel air explosion. I think that silconeoilmight also do a
better job dispersing the reactants.
Michael Michalchik
Sparklers or morning glories are a reliable way to start the reaction.
My next method of choice would be vaporizing an aluminum wire with
wall current. An oxy-acetylene tourch would work, but if you have one
of those anyway...
Michael Michalchik
>
> Dirk
MnO2 is a more powerful oxidizing agent than Fe2O3, but the bp of MN
is about a 1000C lower than Fe so the reaction would be that much
cooler at max T. Iron and Alumina is about as good as you can get end
products with high bp's. I once figured out that you could do about
another few hundred degrees hotter if you substituted Os04 for the
Fe2O3, but osmiun tetroxide is too expensive and toxic to make this
reaction worthwhile. Also, you would give your audience metal fume
fever from aerosolized Mn.
Michael Michalchik
> I assume a touch of KClO3 will also liven it up a bit.
>
> Dirk
Now you are just talking about flash powder. Because of the production
of gaseous end products it can't sustain intense heat in one area the
same way that a true thermite reaction would. Back in highschool I
experiemnted with aluminum and magnesium mixed with oxidizers like
KN03. They went poof with a bright flash of light, but they would be
useless for welding or burning through things and probably wouldn't be
anywhere as good at starting fires or penetrating armor as thermites
because their energy would not be sustained in one place. That is why
thermite is used for incindiaries and flash is used for fireworks.
Dirk Bruere
I'm not talking about stochiometric mixes but adding a small amount to
enable it to be lit easily.
Dirk
donald haarmann
>
> So if I wind up giving this demo to the fire department, what do you
> guys suggest I talk to them about?
>
> I am currently planning:
> Places where thermite mixtures might be found.
> What their legitimate and illegitimate uses are.
> The basic chemistry and properties of the reaction.
> How it can be made.
> The big don'ts with regard to thermite.
> How to cope with it.
> The ways that it could be augmented by a terrorist to make it very
> nasty.
>
---------
I have not followed the complete thread on this as I-Can-Not-Stood-it-No-More!!!
You are looking for a cure for which there is no known disease!!
Where/how is thermite used. The most common use in terms of number of time of usage
is for bonding and grounding (Earthing for the British) of electrical and gas pipes/conduit &c.
The thermit used in these applications is CuO based. Common trade names are:
Cadweld - http://www.cadweld.net/ (Look for the MSDS's for Cadweld and its starter, and
usage infomation.)
thermOweld - http://www.thermoweld.com/
&c.- http://www.exothermicweld.com/
Largest usage by weight is for the welding of iron. All three iron oxides can be used, however,
economy dictates the usage of only one.
Time to put another Urban Legend to rest! Thermite was NOT used except to a very small extent
as an incendiary in WW II, as it was found in WW I not to be effective. Its action being entirely local.
Chances of the FD having to put it out? Close to zero assuming they aren't the ones who ignited it!
How long do you think a 100kg pile would burn? I would guess less than 10 minutes. Given the surface
area increases toward the bottom and the molten material at top will flow down through the pile
igniting the underlying material.
And now for more than you ever wanted to know 'bout thermite!!
-------
Thermit(e) Redux
donald j haarmann
Thermite - the reaction between any of the three forms or iron oxide and aluminium, is
only one of many reactions possible between aluminium and metal oxides. Another
name for aluminium metal oxide reactions is: "Goldschmidt" reactions, in honor of Dr.
Hans Goldschmidt who starting 1895 obtained numerous patents on these and others
using phosphides, arsenides, silicides, and borides. He also coined the term "Thermit"
now a registered trademark owned in the US by Thermex Metallurgical.
The most common used in welding is the combination of ferric oxide and aluminium.
3Fe3O4 [Ferrosoferric (black iron) oxide] + 8Al -> 9Fe + 4Al2O3 5590o F 719 Kcal
3FeO [Ferrous oxide] + 2Al -> 3Fe + Al2O3 4532o F 187 Kcal
Fe2O3 [Ferric (red iron) oxide] + 2Al -> 5360o F 181 Kcal
Magnesium can be used in place of aluminium. However, there are two disadvantages
too using magnesium in place of aluminium. The higher melting point of magnesium
oxide 2852o C vs 2015o C for aluminium results in little if any molten iron. Also,
magnesium is much more costly!
These reaction are of little firework interest. There are, however, two others that are. I'll
post them.
Because the ignition temperature is appx. 2000o C an igniter is required. There are two
standard ones -
Aluminium atomized (fine) 40%
Black iron oxide 29
Barium peroxide 31
Magnesium powder 9%
Barium peroxide 91
Try a little aluminium mixed with a little sulphur, atop a SMALL pile of magnesium
powder.
USE A FUSE!!
BEFORE LIGHTING THE FUSE ASK YOURSELF - What am I going to do with the
resulting mad hot molten iron???? Catching it in water is a really bad idea. It can
explode. Not only can it. IT HAS. Dry sand is best.
---------
Chemical demo goes out of control
An explosion occurred during a chemical demonstration at the University of Illinois,
Urbana-Champaign, earlier this month. The widely used demonstration of the thermite
reaction-which involves the reaction of iron oxide and powdered aluminum to form iron
and aluminum oxide-was part of the university's annual Engineering Open House for
local high school and grade school students. There were 200 to 300 people in the
chemistry lecture hall at the time of the explosion. Four teachers and 23 students were
taken to the hospital, where they were treated and released. The injured suffered first-
and second-degree burns and minor cuts. Chemistry professor Steven S. Zumdahl,
who was conducting the demonstration, says it had just been run successfully using
sand as a receptacle for the molten iron. But when the sand was replaced with water,
something went wrong. Jiri Jonas, head of the department of chemical sciences, says a
committee, including university and local safety experts, has been appointed not only to
determine what went wrong with the thermite demonstration, but also to review all
safety issues surrounding the open house.
March 12, 1990 C&EN
-------
57.4 / Thermit Welding
Welding Handbook
Sixth Edition
Section Three
Part B
Welding, Cutting And Related Processes
AWS 1971
PRINCIPLES OF OPERATION
Basically, thermit is the generic name given to reactions between
metal oxides and metal reducing agents. The usual oxides are
those that have low heats of formation, and the usual reducing
agents reducing agents are those which, when oxidized, have high
heats of formation. The excess heats of formation of the
products, as compared with the starting materials of the
reaction, represent the heat produced by the reaction. The
reaction. Typical thermit reactions is an exothermic one
are as follows:
3FeAl + 8Al ----> 9Fe + 4Al203 (5590'F/3088-C) 719.3 Kcal
3FeO + 2Al 3Fe + AL203 (4532'F/2500-C) 187.1 Kcal
Fe203 + 2Al 2Fe + Al203 (5360'F/2960'C) 181.5 Kcal
3CuO + 2AI 3Cu + Al203 (8790'F/4865'C) 275.3 Kcal
3CU20 + 2AI 6Cu + Al203 (5680'F/3138'C) 260.3 Kcal
3NiO + 2AL 3Ni + Al203 (5740'F/3171'C) 206.6 Kcal
Cr203 + 2AI 2Cr + Al203 (5390'F/2977'C) 546.5 Kcal
3MnO + 2AI 3Mn + Al203 (4400'F/2427'C) 403 Kcal
3MnO2 + 4AI 3Mn + 2Al203 (9020'F/2771'C) 1041 Kcal
[one of these values is wrong! /djh/]
Note that in All of the exothermic reactions listed, Aluminum
has been used as the reducing agent. Magnesium can Also be used,
but it has limited usefulness because of the very high melting
point of the oxide. Slags from magnesiothermic reactions are not
formed at a sufficiently high temperature to be fluid. The use of
magnesium is, therefore, confined to those applications where
fluid reaction products are not desired.
The first reaction in the aforementioned series is the one most
commonly used in thermit welding, and the major portion of this
discussion will refer to it. The proportions are roughly three
parts of iron scale to one part of Aluminum. The theoretical
temperature resulting from this reaction is 5590'F (3088'C).
Radiant heat loss and losses to the reaction vessel, or crucible,
however, reduce this temperature to about 4600'F (2538'C).
Other additions to adjust the metal for chemistry and the slag
for fluidity serve to further reduce the temperature. In
practice, filler weld metal temperatures are about 3800'F
(2093'C). >>The reaction is non-explosive, and regardless of
size, requires less than one minute to complete itself.<< [This
statement applies ONLY TO IRON OXIDE THERMIT. Several thermit's
shown burn that fast! /DJH/] ! No fire hazard is incurred under
normal conditions of handling and storing thermit mixtures, since
an initial temperature of more than 2200'F (1205'C) is needed for
ignition.
To start the reaction, a special ignition powder, or "first
fire" mixture, incorporating peroxides, chlorates or chromates as
the oxidizing agent, and Aluminum dust, or magnesium, silicon, or
titanium powders as the reducing agent are required. This
ignition powder can be lighted by a burning magnesium ribbon, by
the flare of a match, or by a spark. This will, in turn, burn
with enough heat to reach the 2200'F (1205'C) ignition
temperature of the main thermit powder.
Thermit mixtures employed for welding often contain other
materials in addition to the iron oxide and the Aluminum. By the
addition of these materials, variables such as the time and
temperature of the reaction, and the chemical analysis of the
produced weld metal, can be controlled. As an example, additions
of metallic elements either in the form of pieces of metal, which
are melted during the reaction, or in the form of secondary
exothermic reactions chosen from the list of equations, make
possible wide variations in weld metal analysis. By like token,
mechanical properties of the weld metal can be varied over a
broad range. As-cast tensile strengths between 50,000 psi and
130,000 psi, with inversely corresponding elongations of over 49%
in 2-in. to Almost zero, are possible. The metal responds in the
usual manner to heat treatment.
---------
This method of producing Cr is of historical interest:-
Preparation of the metal.-Chromium metal can be prepared by reducing chromium
sesquioxide with carbon in the electric furnace ; or better, by the aluminothermic
process, which is also called, after its inventor, the H. Goldschmidt's process (1905). An
intimate mixture of chromium sesquioxide and aluminium powder, A, Fig. 187, is placed
in a refractory clay crucible so that about two-thirds of the crucible is filled. A mixture of
sodium or barium peroxide and aluminium powder is placed over this, as at B, Fig. 187.
A piece of magnesium ribbon, C, is stuck into the latter mixture, and a layer of
powdered fluorspar, D, is placed over all. The crucible is then set in a tray of sand and
the magnesium ribbon, C, ignited. When the flame reaches the peroxide mixture, B,
THE ALUMINIUM IS OXIDIZED WITH EXPLOSIVE VIOLENCE, AND CARE MUST BE
TAKEN TO PROTECT THE FACE AND HANDS ACCORDINGLY. [emphasis added /djh/]
The heat of the combustion of the aluminium in the ignition mixture, B, starts the
reaction between the chromic oxide and the aluminium, and it spreads throughout the
entire mass in a few seconds. The chromic oxide is reduced to metal, and the
aluminium is oxidized to alumina: Cr203 + 2AI = 2Cr + Al203. When the crucible is
cold, a button of metallic chromium will be found on the bottom. The slag is nothing but
fused alumina which has crystallized so as to form a kind of artificial corundum. This
has been called corubin to distinguish it from natural corundum. The corundum slag is
used as a refractory and abrasive agent. When chromic oxide is reduced, the slag
contains small artificial rubies. In Goldsebmidt's works at Essen, about 100 kilograms of
chromium [forsooth!] are produced at a single charge. The process occupies less than
half an hour. Manganese, iron, and man other metals can be produced in a similar
manner. Titanium, alloyed with iron—ferro—titanium—is produced by the same
process. So much heat is evolved during the reaction that even the most refractory
metals and minerals are melted. Indeed, a temperature equivalent to that of the electric
are-furnace, 3000o, can be generated in a few minutes. The method is in some ways
superior to the electric furnace process-it is quicker, cheaper, and the products are free
from carbon contamination.
JW Mellor 1933
Modern Inorganic Chemistry
CF Popular Science Monthly - September, 1941.
-------
Mellor - INORGANIC AND THEORETICAL CHEMISTRY
[Scanned and you know what that means!]
C. and A. Tissier 12 first noted the reduction of the metal oxides by aluminium they did
not succeed in reducing zinc or manganese oxide in this way; but they reduced iron
oxide, forming an iron-aluminium alloy; there was a strong explosion with copper oxide,
and with lead oxide, 50 grms., and aluminium foil, 2-9 grms., the crucible was broken to
pieces and the doors of the furnace blown off. Aluminium oxide has a very high heat of
formation-about 131.2 Cals., and this is equal to or slightly lower than the heats of
formation of the oxides of calcium, strontium, lithium, and magnesium, but larger than
the heats of formation of sodium, potassium, rubidium, silicon, boron, and most of the
other metal oxides. Hence, unless these magnitudes alter adversely with rise of temp. it
would be anticipated that aluminium would reduce the metal oxides at high temp. Some
such hypothesis guided H. Goldschmidt, who found that the oxides of the alkalies and
alkaline earths are reduced with difficulty by aluminium, but practically all the other
metal oxides are reduced by heating them with aluminium powder, and he obtained
either the metal, or an alloy of the metal, with aluminium, from the oxides of chromium,
manganese, iron, copper, titanium, boron, tungsten, molybdenum, nickel, cobalt,
zirconium, vanadium, niobium, tantalum, cerium, thorium, barium, calcium, sodium,
potassium, lead, and tin. he said:
In a thermite reaction, a metallic compound is reduced by one of several metals or
metallic alloys in such a way that when the mixture is ignited at one place, the reaction
continues of its own accord, so that under complete oxidation of the reducing element,
a fluid slag is formed, while the reduced metal is obtained as a homogeneous uniform
regulus ; if the oxide is used in excess, the reduced metal is free, or practically free,
from the element used as a reducing agent.
The solid oxide is intimately mixed with rather less than an eq. quantity of granulated
aluminium, and is placed in a crucible lined with magnesia. Owing to the high ignition
temp. of the mixture, the reaction is started either by burning Magnesium, or by the aid
of a special ignition powder-a mixture of barium dioxide and aluminium-which is placed
on top of the mixture of oxide and aluminium, and lighted with a match. When the
reaction has been started in one spot it is propagated throughout the mass with great
rapidity. So much heat is generated that the reduced metal is melted. Reductions of this
type are called thermite reaction, or aluminothermic reactions. In these reactions the
beat is developed with great rapidity, and the local rise of temp. is very great-estimated
in some cases to be 3000o in 60 secs. The system may be likened to a furnace from
which gaseous products are not evolved, and in which metals themselves are used as
fuel. The process is employed for the production of carbon-free metals or alloys like
chromium, manganese, molybdenum, ferro-titanium, forro-vanadium, ferro-boron
cupro-manganese, etc. A mixture of finely divided aluminium with ferric oxide or the
oxide of some other metal), approximating to 2AI+Fe2O3, is sold under the registered
name thermit, and it is used in joining or welding iron and steel rails, pipes, etc., and in
repairing fractured parts of macbinery-engine frames, crank-shafts, etc. The process
has been described by W. H. Wahl, E. Stütz, etc. A suitable mould is fitted round the
part to be repaired, and molten iron produced by the thermit reaction is allowed to flow
into the place where the joint is to be made. A. Colani, C. Matignon, R. Trannoy, and H.
Fonzes-Diacon prepared phosphides, arsenides, silicides, and borides by
simultaneously reducing two oxides by the thermite reaction. H. Moissan, E. Wedekind,
A. Stavenbagen and E. Schuchard, etc., have prepared aluminium alloys by this
process. W. H. Greene and W. H. Wahl dissolved the metal oxide in cryolite and
reduced it to the metal by means of aluminium.
H. Goldschmidt also showed that other compounds can be reduced by aluminium
powder—for example, the metal sulphides are more easily reduced than the oxides, as
might be anticipated from the smaller heat of formation. The heats of formation of zinc,
magnesium, manganese, potassium, sodium, strontium, and calcium sulphides are
greater than this, cadmium, iron, etc., less, H. Ditz examined the process with iron
sulphides. The metal suphates react more vigorously than the sulphides. [See: Donald
J Haarmann "The Few, The Proud, The Sulfates" Pyrotechnist Guild International
Bulletin 46:8-13 1985] and O. Matignon said that mixtures of the sulphates and
aluminium powder are often more explosive than with the nitrates. C. and A. Tissier, for
instance, found that a violent explosion occurs when potassium and sodium sulphates
are melted with aluminium. A. Rossel and L. Frank found that the reduction of barium
suphate and of calcium sulphate is attended by a violent explosion; some sulphur is
formed. F. Faktor reduced sodium thiosulphate by heating it with aluminium, and
obtained aluminium. sulphide. 0. Matignon found that the metal Chlorides are not
suitable for reduction by aluminium. on account of their volatility. A. Rossel and L. Frank
reduced sodium chloride with aluminium, and they obtained some chlorine in the
reaction with chromic chloride. The Chemische Fabrik GriesheimElektron reduced
potassium fluoride with aluminium: 6KF+Al=3K+KSAIF6. According to J. W. Richards,
when fluorspar is melted it gives off a little hydrofluoric acid vapour, produced by a
reaction with the hygroscopic moisture, this forms a little aluminium. fluoride; otherwise,
the molten fluoride has no action on aluminium. He also stated that cryolite attacks
finely divided aluminium at a temp. exceeding 1100' with the possible formation of a
subfluoride; but the metal en masse is not attacked. When aIuminium powder is fused
with silver chloride, a silver-aluminium alloy is formed, and when the vapour of
mercurous chloride is passed over heated aluminium, mercury and aluminium
chloride are volatilized, and the aluminium is melted by the heat of the reaction. C. and
A. Tissier found that potassium carbonate is less vigorously reduced by aluminium
than thesulphate, some carbon and alkali aluminate being formed. There was no
deflagration. According to J. W. Mallet, if a mixture of aluminium and dry sodium
carbonate be heated in a carbon or lime crucible, or in a graphite crucible lined with
lampblack, sodium is formed and volatilized, and there remains a regulus of aluminium,
crystals of alumina, aluminium nitride, and carbon. It is assumed that carbon is
separated and sodium aluminate is first formed, and the latter is then reduced by more
aluminium.
12 C. and A. Tissier, Guide pratique do la recherche, do rextraction, el de to
fabrication de Paluminium et des mitaux alcalins, Paris, 1858; Compt. Rend.,
43.1187,1856; H. Goldschmidt, German Pat., D.R.P. 96317, 1895; Zeit. Elektrochem.,
4. 494, 1898; 6. 63, 1899 ; Zeit. angew. Chem., 11. 821, 1898; Electrochem. Ind., 6.
360, 1908; Stahl Eisen, 18. 408, 1898; Liebig's Ann., 301. 19, 1898 ; Chem. Trade
Journ., 71. 539, 1922 ; H. Goldschmidt and C. Vautin, Journ. Soc. Chem. Ind., 17. 543,
1898; C. Matignon, Monit. Scient., (4), 14. 353, 1914; Compt. Rend., 156.1157, 1913;
C. Matignon and R. Trannoy, ib., 141. 190, 1905; A. Colani, ib., 141. 33,1905; A.
Duboin, ib., 132. 826,1901 ; H. St. C. Deville, ib., 44.19,1857; H. Fonzes-Diacon, ib.,
130. 1314,1900; J. W. Richards, Aluminium, Philadelphia, 102,1896; S. Mierzinsky, Die
Fabrikation des Aluminiums und des Alkalimetalle, Wien, 1885; G. Roth, Brit. Pat. No.
6651,1905; German Pat., D.R.P. 172327, 1900 ; Chemische Fabrik Griesheim-Elektron,
ib., 140737, 1902; H. von Dahmen, Brit. Pat. No. 16277, 1900; C. E. Bichel, Zeit.
angew. Chem., 18. 1889, 1905; J. W. Mallet, Journ. Chem. Soc., 30. 349,354, 1876; F.
Faktor, Pharm. Post., 38. 527, 1905; A. Rossel and L. Frank, Bull. Soc. Chim., (3), 11.
200, 1894 ; Ber., 27. 52, 1894; W. H. Wahl, Journ. Franklin Inst., 160.187,1905; E.
Stijtz, ib., 160.435,1905; W. H. Greene and W. H. Wahl, ib., 135. 218, 453, 1893 ; Brit.
Pat. No. 2066, 1893 ; H. Ditz, Met., 4. 787, 1907 ; R. N. Hart, Welding, New York, 1913;
E-Wedekind,Ber.,35.3932, 1902; A. Stavenhagen and E. Schuchard, ib., 35. 909, 1902;
H. Moissan, Bull. Soc. Chim., (3), 15. 1282, 1896 ; C. H. Crowe, Canadian Chem. Met.,
6. 161, 1922; A. Röhrig, Chem. Ztg., 47. 528, 1923; Metal Ind., 23. 125, 1923.
--------
ALUMINIUM AS A HEATING AND REDUCING AGENT.
BY DR. HANS GOLDSCHMIDT AND CLAUDE VAUTIN.
The Journal of the Society of Chemical Industry (6)17:543-545
June 30, 1898
(See also pp. 584 and 612.)
ALTHOUGH it is well known that the oxide of aluminium (Al2 03) is a remarkably
stable body, no experimenters have hitherto taken advantage in a practical way
of the enormous affinity exercised for oxygen by aluminium to effect reductions
of other oxidised bodies. A few experiments on a laboratory scale, chiefly on the
reduction of metallic chlorides, and fluorides, have been recorded, amongst
which may be mentioned those of Wöhler, Tissier, and Deville. Wöhler attempted
to produce the metals chromium arid manganese by heating their chlorides with
aluminium, but only partial success was obtained, as it was found impossible to
obtain the metals free from aluminium. He also produced tin alloy of titanium and
aluminium by heating together titanic acid, cryolite, and metallic aluminium. He
states that the use of cryolite is to cause the formation of fluoride of titanium,
which shows that his object was to bring into action a fluoride of the metal and
not to effect direct reduction of the titanic acid. The brothers Tissier heated
together aluminium with oxide of manganese, but they state that no reaction
takes place. Deville produced an alloy of aluminium and silicon by heating
together the metal and silica, and Beketoff produced a substance containing 33
per cent. of barium by heating baryta with aluminium and barium chloride. Lastly,
Greene and Wahl separated manganese from its oxide by direct reduction.
Although these results are not very encouraging it is a remarkable fact that the
value of aluminium as a deoxidiser has been so long overlooked. It is probable
that the comparatively high cost of the metal and the explosive nature of the
mixtures deterred some from attempting to use it on a large scale.
The fact that metallic aluminium is a powerful reducing agent may be inferred
from the figure 3 representing the heats of combination of aluminium with
oxygen, sulphur, &c. For example, the beat or formation of Al2O3 is about
360,000 calories, while that of [K20] is 97,000. Again the heat of formation of
[Al2Cl6] = 321,000 against [Fe2CI6] = 192,000 and [Na Cl] =97,300, but judging by
results, even these figures failed to promote further research.
In the latter part of 1892 and early in 1893, one of the authors was engaged in
investigating certain processes for the production of aluminium, and for special
reasons it quantity of pure aluminium sulphide was required. Attempts were
made to produce it by the usual text book methods, such as heating alumina in
the vapour of carbon bisulpbide, or heating together alumina, carbon, and
sulphur, but these failed to produce the sulphide in sufficient quantity and of the
required purity. It then occurred to the author to reduce sulphide of lead by
means of metallic aluminium in imitation of the well-known reaction between
galena and metallic iron. To carry but the experiment, about 5 lb. of practically
pure galena were crushed and mixed with the theoretical quantity of aluminium
in coarse lumps to produce Al2S3 and metallic lead in accordance with the
equation—
3 PbS + Al2 = Al2S3 + 3 Pb
The mixture was charged into a crucible, and placed in a furnace. As soon as the
contents of the crucible had attained to it full red beat, reaction took place the
evolution of enormous beat. The contents of the crucible were cast into a mould,
and it was found that the reaction as I expressed above had taken place, yielding
practically theoretical amounts of the products. The aluminium sulphide
produced is of a greenish colour ; it decomposes water readily with the
production of sulphuretted hydrogen, though it may be kept in air-tight tins or
bottles for in indefinite time. It fuses at a clear red heat, and the metal can easily
be obtained from the fused mass by electrolysis. The presence of sulphide of
lead as an impurity is guarded against by keeping a slight excess of aluminium in
the charge, which excess of metal will be found after casting the molten product
as a hard, brittle, and easily detachable button on the surface of the lead.
Aluminium will not alloy with lead, but it will form alloys with iron, silicon, copper
silver, gold, &c. The excess of metallic aluminium therefore performs the double
function of keeping the sulphide of aluminium pure, and of removing all iron,
copper, &c., from the lead, giving to the latter remarkable purity and softness.
Further, by judiciously mixing the aluminium and the galena, this excess button
removes any precious metals which may be contained in the sulphide of lead,
much in the same manner as zinc desilverizes lead in the Parkes process. (The
addition of a small percentage of aluminium to the zinc used in the Parkes
process permits of a higher temperature being used ; it prevents the format on of
(sic ) oxide or zinc and effects better separation of the precious metals.)
The concentration of the precious metals in the excess button presents only a
theoretical interest, as the present price of aluminium entirely excludes its use for
that purpose. This first successful experiment led to further attempts at reducing
the sulphides of other metals in spite of the frequently repeated statement that
aluminium sulphide could be reduced by metallic iron, zinc, copper, &c. The sup-
posed decomposition of aluminium sulphide by metallic iron has been the basis
of numerous patents for the production of aluminium. The patentees describe at
length a process for producing the sulphide, after which the specification draws
to a conclusion with the statement that the sulphide may be decomposed by iron,
copper, or even by lead. As a matter of fact, it is the reverse action which takes
place. Nearly all metallic sulphides, except those of the sodium and barium
groups and magnesium, are readily decomposed by metallic aluminium with the
characteristic feature of the evolution of great heat. So much so that on reducing
common sulphide of iron in a small crucible, the molten iron, free from carbon,
melts into one mass which can be cast into a mould, while the temperature of the
furnace, in which the reaction took place, is some hundreds of degrees below
the melting point of the metal. It is interesting to note that iron produced in this
manner, rising a magnesia-lined clay crucible, is obtained absolutely free from
carbon, the only impurities being traces of aluminium and sulphur, and by using
a small excess of the sulphide the aluminium may be eliminated. Among the
sulphides that are decomposed by aluminium may be mentioned those of cobalt,
nickel, molybdenun, (sic) and zinc.
Our next experiments were carried out with metallic oxides and aluminium; here,
the range of possible reductions extends to the oxides of the alkalis and the
alkaline earth metals, all of which yield up their oxygen, though with difficulty, to
aluminium. Practically all the metallic oxides are reducible by this method, the
chief exception being the oxide of. magnesium. Trials have been made with the
following oxides of metals, all of which are reduced by aluminium, either pure or
in the form of alloys :—Chromium, manganese, iron, copper, titanium, boron,
tungsten, molybdenum, nickel, cobalt, zirconium, vanadium, niobium, tantalum,
cerium, thorium, barium, calcium, sodium, potassium, lead, and tin ; however,
the experiments with some of these metals must not be considered to be
concluded.
The failure of the brothers Tissier to effect reduction of the oxide of manganese
is probably due to one of two causes ; either they failed to heat the charge
sufficiently to promote reaction, which is improbable, as the temperature required
is not high, or else they had not the aluminium in It form best suited for the
purpose. We find that nearly every ease the aluminium must be in a powdered or
granulated condition, and intimately mixed with the finely crushed oxide or
sulphide to be reduced. There are, however, a few exceptions to this rule, for
example, to effect the reduction of lead salts, it is not advisable to have the
aluminium in it very fine state of division, because owing to the enormous heat
produced: a simultaneous reaction throughout the whole charge would cause
sudden vaporisation of the lead, with the result that the whole charge would be
blown out of the crucible with explosive violence.
We have found that aluminium, like lead and other metals, can be easily
granulated by agitating the molten metal in a suitable vessel at the moment
when on cooling it reaches certain critical temperature just between the solid and
liquid state.
As before mentioned, the most striking feature of all these re-actions is the
evolution of enormous heat. So great is the temperature produced that the most
infusible metals are melted, while the slag, consisting of nothing but alumina, is
sufficiently molten to allow all the reduced metal to sink through it and to collect
into one fused mass. It is estimated that the temperature produced is tit least
3,000o C, and by means of this heat, work can be done which hitherto required
the electrical furnace for its performance.
The authors have made practical use of the reducing power of aluminium in the
production of chromium from its oxide oil the large scale, but they soon
recognised the fact that to make this process commercially successful, it would
be necessary to do away with external heating of the charge, both on account of
high fuel costs and on account of crucible wear.
It has been proved by experiment that it is unnecessary to heat the whole of
the mixture from which the metal is to be obtained to the temperature at which
reaction takes place ; that is to say, it is only necessary to, start the reaction at
one point of -it given charge as the local heat produced is sufficient to cause the
whole charge to react the heat passing gradually through the entire mass. In the
reduction of chromic oxide by aluminium. the temperature to which it is
necessary to heat one point of the charge before the reaction takes place, is
about 1,050o C, or a bright red heat.
At first, however, it was found very difficult to cause the mixture to ignite at
one point without external heating, but this trouble wits overcome by using a "
fuse " of a highly inflammable nature which was capable of setting up an
initial impulse which subsequently caused the combustion of the whole charge.
The action of the " fuse " or " cartridge " is also based on the heat produced by
oxidising aluminium. By supplying the metal with a compound rich in oxygen a
highly inflammable mixture is obtained, which at the same time produces intense
heat. Of the various compounds tried, peroxide of barium was found to give the
best results though various other per-salts may be used. A suitable mixture of
the metal with the peroxide is made into it paste with a cementing material,
which on hardening forms a cartridge, capable on ignition, of imparting the
requisite initial temperature tothe charge. The cartridge is supplied with a piece
of magnesium ribbon whereby its ignition is readily accompIished. By this
process a considerable amount of chromium has already been produce
by the author.
A few experiments illustrating the heating effects of this process will be shown,
and it is probable that, using cheap impure aluminium and it cheap source of
oxygen such as oxide of iron, that the process as a beat producer possesses
considerable commercial value as it can be supplied in cases .where it would not
be convenient to use other sources of beat. For heating purposes alone, it would
be necessary to add some material such as magnesia or lime to the mixture of
metal and oxide so as to prevent the running together of the metal and slag
produced; thus leaving, after firing, a brittle cindery slag, which can easily be
removed by tapping with a hammer.
For heating purposes, its in the production of metals, the cartridge would have
to be used to start the reaction in the mixture which is to produce the heat.
As we have already pointed out, a very important use to which the process may
be put is for the production of pure carbon-free metals, though future work will
probably lead to other important applications ; nor must it be forgotten that by
this method not only pure metals but also alloys can be obtained, many of which
it is exceedingly difficult to produce by another process. For example, the
authors have produced ferro-boron containing 20 to 25 per cent boron ;
farro-titanium (20 per cent. and 40 per cent. of titanium, the latter being
non-magnetic) ; ferro-chrome; chrome-maganese &c. But we hope to show by
means of experiments that the adaptation of this method to heating purposes
pussesses very wide application, and it is possible that it, point of utility it will
rival the reduction process.
It may be mentioned that the alumina shag produced possesses properties
superior to ordinary rock corundum both as to hardness and texture, owing
probably to the total absence of water in its composition. The slag also
possesses other interesting characteristics. Thus for example, the slag formed
during the production of chromium will be found to be interspersed with red
crystals which must be taken to be rubies, chromium being the colouring matter
of the natural ruby. The% are, however, of no value oil account of their small
size.
Finally, phosphates, sulphates and nitrates are also reduced by aluminium,
though the latter act feebly in comparison with the sulphates.
The authors wish to acknowledge the useful work done by -Mr. Hugh K. Picard,
who, as assistant to one of them, successfully carried out most of the earlier
experiments.
APPENDIX.
The following experiments will serve to illustrate the paper :-
1. Burning of the cartridge, the so called " inflammable-cherry."
2. Heating of an iron rivet of 1 lb. weight by means of it cemented heating
mixture, which surrounds the rivet so that the gradual passing of the heat is
visible.
3. White heating of it rivet of about 7 lb. weight, the heating mixture being
surrounded with sand. As the heat is kept from dissipating by the sand, the
whole mass can be put, as shown, into a wooden tub.
4. Application of the method for hard-soldering a flange on to a tube of 1 in.
diameter; instead of putting the flange (prepared with hard solder and borax as
the coppersmiths do it) into a charcoal fire, it is placed in the heating mixture. For
this purpose only about 3 1/2 oz. of aluminium are required. If impure or raw
aluminium be used at, say, 6d. per pound, the total expense will be 1 ½ d. for the
heating mixture.
5. Production of wrought iron from oxide of iron and aluminium. The reaction in
this case is brought about without the aid ot a cartridge, but by means of a
mixture of peroxide of sodium (Na02) and carbide of calcium (CaC2), ignited by a
drop of water. The same effect is produced by a mixture of peroxide of sodium
with aluminium, magnesium, zinc, or sulphide of antimony.
6. Production of a regulus of metallic chromium of about 10-12 lb. weight in a
magnesia-lined crucible. In this crucible a mixture of Cr203, and AI2, is put, and
ignited then a further quantity of this mixture is added till the crucible is filled up.
The reaction lasts only a few minutes.
7. Production of sodium (Na) from caustic soda (NaOH) and aluminium in it
paper tube. The sodium distils off with a bright flame. The initial temperature of
the reaction is very low ; this experiment is therefore interesting, as aluminium as
is well known, has been made with sodium from chloride of aluminium (Al2Cl6).
Beketoff found is 1888 that aluminium decomposes the hydroxides of the
alkalis, and be distilled potassium and rubidium in an iron tube. Deville,
however, expressly mentioned that he did not succeed in decomposing the
molten alkalis with aluminium.
8. Reaction between a mixture of gypsum (CaS04) and aluminium in a paper
tabe ; the temperature of reaction is here very high. First the paper tube is set on
fire by a match, but the temperature so produced not being high enough to start
the reaction, a cartridge is applied, and then the mixture goes off like a rocket.
The following metals, alloys, &c. were exhibited:-
Metals.
1. Chromium, containing, 95-97 per cent. Cr and 3-4 per cent. Fe.
2. Chromium 99.5-99.8 per cent. Cr, containing also trace of silicon and iron.
3. Manganese, 98-99 per cent. Mn.
4. Iron, hammered, equal, to best pure steel.
5. Vanadium, chemically pure.
6. Niobium, chemically pure.
Alloys.
7. Iron, containing 40 per cent. of titanium (not magnetic).
8. Iron, containing 20 per cent. of titanium (magnetic).
9. Iron, containing 25 p-r cent. of boron.
10. Manganese, containing 30 per cent. of chromium for making alloys with
copper, manganese, and chromium (so-called chrom-manganin).
11. Copper, containing 10 per cent. of chromium (has nearly the colour of
copper).
12. Alloys of lead and barium.
13. A plate of iron of about half an inch in thickness in which a hole has been
melted by the heating mixture.
14. Different pieces of corundum (slag, fused Al203) some of these pieces
containing crystals of rubies; also corundum crushed.
15. A piece of bronze.
Breaking strain in lb. per sq. in. = 27.874 tons, or 62,440 lb.
Elongation = 34 per cent.
ALUMINIUM AS A HEATING AND REDUCING AGENT (IN THE PRODUCTION
OF CHROMIUM AND OTHER METALS).
BY DR. HANS GOLDSCHMIDT AND MR. CLAUDE VAUTIN.
(This Journal, 1898, 543.)
Discussion.
Dr. S. RIDEAL congratulated the author and Dr. Goldschmidt on the success of
the brilliant experiments they had seen, and asked if he was right in
understanding that metallic calcium was reduced by the action of aluminium on
calcium sulphate. if so, he would like to know what steps were taken for ensuring
the permanency of the product, as he would have expected that, if the reduction
were performed in air at the temperatures that were produced, it would have
rapidly re-oxidised to the condition of lime.
Dr. GOLDSCHMIDT explained that he was not able to obtain pure metallic
calcium. He had obtained an alloy of iron and calcium, and was so covered up
during the reaction that there was a loss of only about 1 per cent.
Mr. J. B. C. KERSHAW regarded the process as one which might have important
industrial results. He need hardly remind the authors, however, that there were
other methods in use for the production of metallic chromium, and that therefore
the success or non-success of this particular process would depend entirely on
the economical aspect of the question. In their paper they had not given any
particulars as to the cost of the process generally, or of obtaining the aluminium
in the powdered form; and it would be of great interest to have definite
information from them upon this point of cost.
Dr. GOLDSCHMIDT replying to Mr. Kershaw, said that the process was cheaper
than any other now known. The cost of the chromium and ferrochromium was
about 2 marks per kilo., say, a shilling a pound. The chromium in commercial
ferrochromium contained about 10 per cent. of carbon. It had been mentioned
that it was possible to reduce the slag back to aluminium, even if it were not sold
for the purposes to which emery was now applied. Therefore, that would
considerably reduce the cost chargeable to the production of the chromium.
Mr. B. KITTO enquired whether the author had succeed in reducing the oxide of
uranium. He believed that Moissan had succeeded in getting a carbide of the
metal fairly pure; still that was not uranium. Messrs. Vantin and Pickard had
about three years ago, tried some oxides of uranium with which he had supplied
them, and succeeded in getting a strong uranium alloy of about 66 per cent., the
rest being aluminium. Since that he had heard that metallic uranium had been
obtained by the process, and would like to know if that was correct and if it had
been proved by analysis to be uranium, and not an alloy. He had himself tried
the ordinary text-book process of reduction from chloride, but without success.
He would also like to ask which of the oxides of uranium Dr. Goldschmidt had
operated upon.
Dr. 0. J. STIEINHART desired to know whether the presence of carbon in
chromium acted deleteriously in the manufacture of chrome-iron or chrome-steel;
for, if such was not the case, the ordinary method of working would be cheaper
than that brought forward by Mr. Vautin. It was to be remembered that they had
to deal with chrome-iron ore containing 40 per cent. of chromium, and costing 5l.
. per ton, whereas chromic oxide alone cost more than that, and, in addition, they
had the expense of the preparation of the alumina, &c.
Dr. GOLDSCHMIDT said that the cost of the chromium in the chrome iron-ore
was very small—only about a penny, whereas the cost of reduction by the
ordinary method was very great. Moreover, in making the chromium for this
purpose he avoided all cost for crucibles. That was a great saving, which
enabled him to compete successfully with other processes. They had no difficulty
in disposing of the pure chromium as fast as it could be made. In fact, many
works were already abandoning the use of nickel in favour of chromium.
Mr. W. F. REID asked if the author had tried any experiments with regard to the
reduction of tungsten. He presumed not, as he did not see that metal among the
specimens. With regard to the very pure chromium exhibited, he would be glad
to know if the author was at liberty to state how he obtained the oxide from which
it was produced.
Dr. GOLDSCHMIDT replied that it was obtained from the chrome-iron ore and
chromates, and the process was performed easily and cheaply.
Mr. REID, Continuing, said he would be glad to know roughly what the process
consisted in.
Dr. GOLDSCHMIDT, replying, said it was no secret ; the chromates were
reduced with coal. It was not necessary to have a very highly crystallised
chromate, and therefore the cost of the oxide, when made in large quantities,
was very small.
Mr. W. CROWER asked if any experiments had been made with vanadium, and
whether that metal also was obtained in the pure state.
Dr. GOLDSCHMIDT said that it was obtained nearly pure. It was contaminated
only with a little iron, and the operation was performed as with chromium and
without much difficulty. Further replying to Mr. Reid's question, he would add that
they had succeeded fairly well with the redaction of tungsten, but had not got it
quite pure. The work, however, was easier than with uranium. He had made
alloys of tungsten with both copper and iron, but to obtain the pure metal was
very difficult, and that was a matter upon which he was still experimenting.
[650] Mr. BERTRAM BLOUNT, referring to a specimen of iron exhibited, said
that that was probably the greatest curiosity in the room, as he understood that it
was absolutely pure metal. If so, he would suggest that it would be exceedingly
interesting to add the analysis of it to the paper. It would be very valuable as a
basis for experiments in the production of alloys, starting with pure material.
Dr. GOLDSCHMIDT said that the specimen of iron was not quite pure. It was
made from a pure oxide which was very hard to obtain. He could not at the
momment remember the exact analysis, but he thought he might say that it con-
tained no aluminium, only a littlle silicon from the aluminium used in the
reduction.
Mr. E. ACKERMANN enquired if the author could state whether in his reaction be
obtained a temperature equal in intensity to that of the electric furnace, and
whether the reduction might not possibly be more economically effected by
electric methods. The reduction of certain oxides by aluminium alone might be
very useful where an electric furnace was not available or the quantity of metal
required was relatively small. Calcium carbide for instance, could be obtained on
a small scale, both electrically and chemically. But on the large scale it could
only be prepared by electrical methods, and the same with aluminium. Using an
electrically obtained product on a large scale as a substitute for electricity did not
appear to afford much economical advantage. Would it not be of advantage to
use some other body for the purpose of the reduction, such as barium peroxide
or iron filings, and to start the reaction by means of some other substance, such
as liquid oxygen ?
Mr. H. L. SLMAN felt deep interest in the paper before the meeting, as he was
one of those who was fortunate enough to witness some of the first experiments
made with the method. By these means he had seen considerable ingots of pure
metallic molybdenum, uranium, and vanadium produced for the first time in the
world's history. On a later occasion, in view of the intense heat evolved, it was
proposed to measure the temperature of the reaction, and Prof. Roberts Austen
attempted this with his electric thermo-couple. The crucible was prepared as
usual for a chromium reduction and heated, and in a few minutes the reaction
occurred. The spot of light from the reflecting galvanometer, which up to this
point had moved but slowly, then rapidly traveled round the scale, and upon
removing the pile for inspection it was found that the heat had been so great that
the immersed portion of the thermo-pile, with its platinum-rhodium terminals,
had disappeared altogether into the reaction. He believed he was correct in
saying that already, in Germany, large quantities of metallic chromium were
being produced by this method for the manufacture of the chrome-steel for which
Messrs. Krupp and Co. were famous. It was interesting to learn that the slag
produced was applicable to the same uses as corundum. Altogether be regarded
the process as one of the most elegant and complete reactions he was
acquainted with.
Mr. CLAUDE VAUTIN having been invited to reply, said that Dr. Goldschmidt
had so ably replied to questions that had been put that he had but little to say.
Referring to Mr. Ackerman's remarks, however, he might observe that the
temperature of burning iron into oxide was several thousand calories less than
that generated by the burning of an equal number of molecules of aluminium. In
fact, results were obtained by the combustion of aluminium that were not
possible in the electric furnace. Dr. Goldschmidt had made some experiments for
determining the temperature reached, and estimated it up to 2,900o C. The
process was already in practical operation, and the demand for chromium was
so great that it was sufficient to use up the present production of aluminium for
the purpose of reducing the chromic oxide. He understood the demand was
attributable to the greater certainty of composition as compared with the use of
ferrochromium and the freedom from carbon. He quite agreed with Mr. Blount
that the specimen of iron shown was one of great chemical curiosity. He
understood that although it contained a little silicon there was no carbon present.
High Temperatures, New Process for the production of, and for the Preparation
of Metals Fusible with difficulty, and Free from Carbon. Goldschmidt. Zeits. f.
Elektrochem. 1898, 4, [21],491-498.
In:- The Journal of the Society of Chemical Industry June 30, 1898
THE author shortly reviews previous work on the use of aluminium in producing
high temperatures, and then describes the method he adopts. As is well known,
an extremely violent reaction takes place when aluminium unites with oxygen,
the estimated temperature of the reaction being about 3,000o C. In order
practically to make use of the high temperatures thus obtained, the chief difficulty
is so to moderate and control the reaction that it will perform the required work.
The first point to be noted is that it is not necessary to heat up the whole of the
reacting mass to the temperature of ignition. It is sufficient to start the
combustion at a single point only, but this in itself presents some difficulties. In
the preparation of metallic chromium from a mixture of its oxide with powdered
aluminium, these difficulties may easily be overcome by applying at any
convenient point a small quantity of a mixture of aluminium with a more easily
reducible oxide, or preferably a peroxide. Lead oxide, copper oxide, potassium
permanganate, and many other substances may be employed for this purpose.
One great advantage of this process is that it admits of the preparation of pure
metals free from aluminium ; the only precaution which requires to be observed
is that the oxide to be reduced must be present in slight excess.
The. process is capable of two main applications. In the first place the heat given
off by the combustion of a mixture of aluminium. with any convenient oxide may
be utilised for heating purposes only (welding, &c.), or, secondly, the reducing
power of aluminium at a high temperature may be used for the preparation of
pure metals, or alloys. in either case only slight alterations in the mode of
working are necessary. If a moderate heat be required, the reacting mass is
diluted by the addition of some inert substance, which, at the same time,
prevents the whole mass from melting. A convenient mixture of this sort is
composed of aluminium. and the cheapest available oxide (e.g., iron ore, sand,
&c.), which is then diluted either with a large excess of the same oxide or with
magnesia, lime; &c. If, on the other hand, the metal itself be required, a large
excess of the oxide must be avoided, so that the heat which is generated will not
only melt the metal, but also the slag (corundum), which then protects the
regulus from the action of the air.
The following experiments illustrate the applications of the process :—A rivet
weighing 3 kilos., such as is used in the construction of bridges, is surrounded by
a mixture of oxide of iron, sand, &c., and powdered aluminium, and almost
wholly embedded in sand contained in a wooden box. On the top of the small
exposed portion of the aluminium mixture is laid a small ball prepared by mixing
aluminium powder with a more easily reducible oxide, and into which is inserted
a short length of magnesium ribbon. The reaction is started by setting fire to the
magnesium ribbon, and as soon as this is done more sand is placed on the top
in order to keep in the heat. If the contents of the wooden box are emptied out
after a short time it will be found that the rivet is white hot and ready for forging.
In a somewhat similar way 1-in. iron pipes may be hard soldered at an estimated
cost of about 2d. ; or, two pieces of wrought iron may be fused (welded)
together. The joint so obtained is satisfactory, as can be shown by sawing the
pieces through at the joint. It is claimed that such a joint is better than that
produced by electric welding, owing to the greater uniformity of heat. By
diminishing the quantity of inert material, the iron in the above experiment may
easily be melted. Holes may be made through ½-in. wrought-iron plates by
igniting some of the mixture on them, and adding more, if necessary, as soon as
the reaction has started.
In order to reduce chromium from its oxide, a mixture of this and powdered
aluminium is made and introduced into a crucible lined with magnesia. The
reaction is started as before, and the mixture then added continuously until the
crucible is fall. After cooling, the crucible is broken open and the regulus of
metallic chromium removed. At the meeting of the German Electrochemical
Society, at which the author communicated his paper, he showed a mass of
chromium weighing 25 kilos. prepared in this way. By making two apertures in
the crucible, one for the introduction of the mixture and the other for the outflow
of the chromium, the process may be worked continuously, as in the case of the
electric furnace.
It is claimed that the temperature attained is higher than in the ordinary electric
furnace, and that a given quantity of material can be put through in a shorter
time. Moreover, the chromium is also free from carbon or carbides. The slag
(alumina) produced in the furnace may be reconverted into aluminium and used
over and over again, or it may be used for polishing, since it possesses certain.
advantages, over emery.
Almost all metals may be reduced from their oxides in this way, and the yield is
nearly theoretical. The different alloys, e.g., "chrom-manganin,"
copper-chromium, &c., can also be prepared. The slag from the furnace contains
minute rubies, which owe their colour to chromium.
For the preparation of pure metals it is necessary to use pure aluminium, but for
heating purposes only, crude (50 per cent ) aluminium may be employed.
Besides oxides the oxy-salts of certain metals may be reduced in the same way.
The author, looks upon aluminium as a " heat accumulator," since it is possible to
transport it, and by its union with oxygen develop, wherever necessary, an
amount of energy corresponding to that which was originally required for its
preparation.-J. S.
--------------
Aluminium as a Reducing Agent, &c.
L. Franck. Chem. Zeit. 1898, 22, [25], 236-245.
In:- The Journal Of The Society Of Chemical Industry. 17, [6], 612-613.
June 30,1898
Action of Aluminium on Phosphorus Compounds—Phosphorus vapour when led
over powdered aluminium, heated to a dull red beat in a current of hydrogen,
combines with it with incandescence, forming a dark greyish-black unfused
mass, which is decomposed in contact with moist (normal) air, forming PH3, and
leaving a greyish-white powder. It is decomposed also by water, aluminium also
by water, aluminium hydroxide and a brownish-black residue being left ; and by
acids and alkalis, which dissolve it almost completely with evolution of PH3. The
compound remains unaltered when heated in air.
At more or less elevated temperatures, all phosphoric, acid compounds (meta-,
pyro-, and ortho-salts alike) are decomposed by aluminium. Metaphosphates,
however, undergo the most complete change, according to the equation—
6NaP03 + 15AI = 6NaAl02 + 2Al203 + Al5P3 + P3
The addition of silica effects the release of the remaining phosphorus, thus :—
6NaPO3 + 10AI + 3Si02 = 3Na2Si03 + 5Al203 + 3P2
Calcium and magnesium salts are as efficacious as those of sodium, but the
superphosphates of commerce are not available for the production of
phosphorus in this manner. If, however, bone ash be decomposed by
hydrochloric acid instead of by sulphuric acid, a material suitable for the purpose
is obtained.
Hence phosphorus may be produced, with almost quantitative completeness of
yield, at relatively low temperatures, and the reduction may be demonstrated in
the apparatus shown in the annexed figure. Hydrogen generated in A is dried by
the sulphuric acid bottles B, and is then passed through the Fresenius
safety-tube C to the combustion tube D, which is 0.5 m. long, and contains a
porcelain boat, d, carrying the charge of 2.1— 2.5 equivalents of Al, six
equivalents of NaPO3, and two of silica (Kieselguhr). Beyond D is the condenser,
E, and a trough of water, into owing to the resulting reaction. After cooling in the
same gas, the residue was found to consist of Al203 and amorphous carbon ; but
it gave a small quantity of an evil-smelling gas when treated with hot dilute HCl
so that traces of an aluminium carbide must have been formed. No carbon
monoxide was detected throughout; but the reaction corresponded almost
exactly with the equation 3CO2+4AI = 2Al203+3C. Aluminium sheet and wire
heated in a current of C02 becomes covered with a black crust ; at the same
time is brittle, and is partly oxidised, partly converted into a carbide.
Action on Carbon Monoxide.—An exactly similar result was obtained by beating
aluminium powder in CO. The reaction is 3CO + 2 Al = Al203 + 3C ; but, as with
C02, a trace of carbide is formed.
Action on Carbonates.—Alkaline carbonates and aluminium mixed in equal
proportions according to the equation Na2C03 + 2AI = Al203 + C + Na2, and
heated to a red heat, became incandescent, and gave alkali-metal and
amorphous carbon. Lithium, sodium, and potassium were thus reduced, the
latter with almost theoretical yield. No potassium carbide was observable.
Calcium, barium, and strontium were reduced in the same way, and barium
crystals were sometimes obtained, but never crystalline carbon. Nevertheless,
some aluminium carbide and a little nitride were also formed.
Aluminium and Carbon.—he author confirms Guntz and Masson's statement
(this Journal, 1897, 244) that the presence of aluminium iodide or chloride
favours the formation of carbide when Al is heated in CO or C02, but he reaffirms
the correctness of his own general equations given above. Aluminium powder
heated with lampblack appears unchanged, but evolves much hydrocarbon gas
when placed in water. The excess of lampblack could not, however, be removed.
Much carbide may be formed by direct combination (Deville to the contrary
notwithstanding), but the reaction is never complete ; and Moissan's carbide,
A4C3, has not been obtained except in the electric furnace.
Action of Aluminium on Oxides.—Copper oxide (cuprous or cupric) mixed with
the correct proportion of aluminium powder for reduction, and heated gradually,
reacted suddenly, with a report like that of a gun. The glass tube was shattered
and small copper shot were found. With an excess of aluminium, the residue was
an aluminium bronze. Silver oxide was similarly attacked. Beryllium was also
reduced at a red heat, but quietly, and with only slight incandescence. Calcium
could be partly reduced from lime, and calcium alloys could thus be readily
obtained. Strontium was reduced from the oxide with a more marked rise of
temperature. Baryta is much more readily, and is indeed almost completely
reduced, with distinct incandescence. Zinc oxide is reduced with quiet
combustion and a blue white luminous flame. Cadmium and mercury and lead
oxides also yield metal, the former quietly, the second almost at once, and the
last-named with explosion. Boron, silicon, phosphorus, and arsenic also, are all
separated in the elementary state on beating the oxide with powdered
aluminium. Iron, manganese, cobalt, nickel, and molybdenum are all partly
reduced ; in the electric furnace new compounds are thus produced.
Action on Sulphates and Chlorides.—Barium (or other) sulphate, mixed with
excess of aluminium powder and heated, explodes with a loud report, shattering
the glass tube in which it is held. Finely divided sulphur and sulphides are among
the products of the reaction. Sodium, potassium, calcium, and barium chlorides,
when melted, yield metal on the introduction of aluminium powder, the two latter
reacting more rapidly and completely.
Action on Sodium Peroxide.- Aluminium powder mixed with sodium peroxide
explodes at a red heat. If the mixture be moistened with water it inflames
spontaneously.
-- W. G. M.
--
donald j haarmann - colophon
Repeating Decimal
Michalchik at micha...@aol.com wrote on 8/2/02 5:04 PM:
Lighting a short section of magnesium ribbon seems to do a good job.
Bill
donald haarmann
>
> Actually not much at all happens unless you light the thermite. Your
> audience might get pretty bored.
> How about using MnO2 instead of FeOxide? Any idea what will happen?
>
> Dirk
>
-------
Yup. Based upon a single experience >45 years ago!
You get one large HOT PUFFFF. Which cut (melted) the top/front
most of my then abundant head hair off like a knife!! A couple
of inches lower ........ I would now be using a brail keyboard!!!
For the brave — here is an even more exciting thermite.
---------------------
Abstracted from:—
Föredrag vid PYROTEKNIKDAGEN [Pyrotechnic Day] 1971
Stockholm den 10 maj 1971
Aluminium Powders For Explosives And Pyrotechnics
Gustaf Windqvist
Aluminium powder in explosives
As can be seen from the name of the article, I have tried to deal only with
aluminum powder for explosives.
Mainly I have tried to do this because I do not have any first-hand experience of
explosives and in the audience there is a number of chemists from the explosives
industry, who could contribute to the discussion of the use of metal powders in
explosives and pyrotechnics
As a final vignette I might be permitted to show a rather funny picture of an
explosion in water, which I had the improbable luck to take with a common camera
more than 20 years ago.
At the company we were playing with certain thermite charges, who were
supposed to have a certain effect in undercooked water streams. One of these charges
contained atomized Aluminium powder A 80 and copper oxide in an equivalent mixture.
If such a charge was lighted by a generator-gas match in air, it burned quickly and if it
was lighted by No 8 detonator it detonated and you got a beautiful copper-cloud in the
air. We thought that if it was used under water, with a generator-gas match, it would
burn quickly, but to our surprise, if not a pure detonation, we got a very fast deflagration
I succeeded in taking this photograph of the water-bubble, which emerged just before it
burst You can see a tendency of bursting on the top, and the white dots are
white-glowing charge. See figure 3.
[Two possibilities come to mind—
The temperature of the reaction may have been sufficient to dissociate water into
hydrogen and oxygen, which then explosively recombined. Or this may be a classic
if poorly understood “liquid metal water explosion.” Also — Aluminium and water can be
detonated. djh/]
donald j haarmann
-----------------------
A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There shallow draughts intoxicate the brain;
And drinking largely sobers us again.
Alexander Pope
1688-1744
Terry Wilder
"donald haarmann" <donald-...@worldnet.att.net> wrote in message
news:pGJ29.21007$Kl6.1...@bgtnsc04-news.ops.worldnet.att.net...
Bill Nelson
> How about using MnO2 instead of FeOxide? Any idea what will happen?
It would be a somewhat more vigorious reaction.
--
Bill Nelson (bi...@peak.org)
Michael Michalchik
things in my Demo. I never claimed that this was a high order threat,
much more a point of interest. Though rare, there have been industrial
accidents involving thermite and the possibility exists of its use as
a weapon of terror.
SNUMBER6
>Another
>name for aluminium metal oxide reactions is: "Goldschmidt" reactions, in
>honor of Dr.
>Hans Goldschmidt who starting 1895 obtained numerous patents on these and
>others
>using phosphides, arsenides, silicides, and borides. He also coined the term
>"Thermit"
>now a registered trademark owned
>in the US by Thermex Metallurgical.
Thanx for that info about where the trademark now resides ... I used to work
for the original company ...
In the US ... the company that was once the Goldschmidt Detinning Company
became the Metal and Thermit company when during WWI the German named company
could have political problems ... It remained as such until 1962 when they no
longer made Thermit, had expanded into many chemicals and became M&T Chemicals
... American Can Company bought them up and ran them as a wholly owned
subsidiary until they divested the chemical part (but kept the old detinning
part which they shortly closed down) to Elf Aquitaine ... who not long after
merged it first with Atochem then again with others ... until now it is either
gone or merged into the nether world of corporate bureaucracy ...
In the Village ....
I am not a number ... I am a free man !!!!
Wim Libaers
news:aifvvj$3h4$2...@quark.scn.rain.com:
> In alt.engr.explosives Dirk Bruere <art...@kbnet.co.uk> wrote:
>
>
>> How about using MnO2 instead of FeOxide? Any idea what will happen?
>
> It would be a somewhat more vigorious reaction.
>
Platinum or gold oxides might be interesting. Shoudl offer even more
energy. Or perhaps tungsten oxide, because the metal melts at high
temperatures it could be hotter.
--
Wim Libaers
Remove DONTSPAM from my reply address to send me mail.
smeltsmoke
Do all metals oxidize? I KNOW gold does so at a MUCH slower rate than
iron (if any) I would think the same of Platinum. I will watch for a
reply from one who knows. Either way, I am sure the costs would be
prohibitive at best.
Smeltsmoke
Dirk Bruere
"smeltsmoke" <no_email@please_post.net> wrote in message
news:3d4c0e66...@netnews.worldnet.att.net...
Make that silver oxide then.
Dirk
Don Thompson
occured in a CO2 rich atmosphere. The "self rescuer" that every underground
miner carries on his equipment belt converts CO2 into CO and O2 so that the
miner may (hopefully) reach good air in an underground fire emergency.
--
Don Thompson
Ex ROMAD
"Michael Michalchik" <micha...@aol.com> wrote in message
news:20f4bb84.0208...@posting.google.com...
> LOUIS <Loui...@SKYNET.be> wrote in message
news:<3D46F493...@SKYNET.be>...
> > N2 would explode due to strong dilatation (from -190°C to 3000°C).
> > Never use water! but in very very large amount...tiny amounts will
> > propagate the burning mix in all directions with tiny explosions!
> > Carbon would be of no use since Al is much more electropositive than it,
>
> Though this is true, remember Le Chattliers principle, if the carbon
> gets to the oxygen first the oxygen will be gone in the form of carbon
> dioxide before the aluminum has a chance to get to it. I suggested on
> a couple of the other groups that a low viscosity dispersion of
> graphite in a low carbon silicone oil might work because the oil would
> seperate the particals and allow the graphite to penetrate the
> mixture, the graphite would consume oxygen without the production of
> much heat, CO2 would carry heat away from the reaction as would the
> decomposition and combustion of the silicone oil. All this might lower
> the temp enough and seperate the particals enough to interupt the
> reaction.
>
> So if I wind up giving this demo to the fire department, what do you
> guys suggest I talk to them about?
>
Uncle Al
>
> At thermite temperatures CO2 is an oxygen donor. Many a mine fire has
> occured in a CO2 rich atmosphere. The "self rescuer" that every underground
> miner carries on his equipment belt converts CO2 into CO and O2 so that the
> miner may (hopefully) reach good air in an underground fire emergency.
The Hopcalite breather oxidizes CO to CO2. The reaction is quite
exothermic. Instruction before entering a mine includes notice that
burning your mouth and throat is not as bad as dying on the spot.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
Christian Jesch
>
> At thermite temperatures CO2 is an oxygen donor. Many a mine fire has
> occured in a CO2 rich atmosphere. The "self rescuer" that every underground
> miner carries on his equipment belt converts CO2 into CO and O2 so that the
> miner may (hopefully) reach good air in an underground fire emergency.
Would be a nice idea to give someone a mixture of O2 and CO. He'll
surely be thankful for it ...
Additionally, the Boudouard equilibrium (that you probably meant) gets
to 20% CO + 1/2 O2 at 600°C. A bit high for a breathing aparatus, hm?
CJ
Don Thompson
get hotter than the hubs of hell.
--
Don Thompson
Ex ROMAD
"Uncle Al" <Uncl...@hate.spam.net> wrote in message
news:3D4C2A28...@hate.spam.net...
Don Thompson
gold (III) oxide
a.. Formula as commonly written: Au2O3
b.. Hill system formula: Au2O3
c.. CAS registry number: [1303-58-8]
d.. Formula weight: 441.931
e.. Class: oxide
Synonyms
a.. gold (III) oxide
b.. gold oxide
c.. auric oxide
d.. digold trioxide
Physical properties
a.. Colour: red or brown
b.. Appearance: crystalline solid
c.. Melting point: 150°C (deomposes)
d.. Boiling point:
e.. Density:
Element analysis and oxidation numbers
For each compound, and where possible, a formal oxidation number for each
element is given, but the usefulness of this number is limited, especially
so for p-block elements in particular. Based upon that oxidation number, an
electronic configuration is also given but note that for more exotic
compounds you should view this as a guide only. Element % Formal oxidation
state Formal electronic configuration
Au 89.14 3 [Xe].4f14.5d8
O 10.86 -2 [He].2s2.2p6
Synthesis
Not available
Isotope pattern
What follows is the calculated isotope pattern for the Au2O3 unit with the
most intense ion set to 100%.
Formula: Au2O3
mass %
442 100.0 __________________________________________________443 0.1 444
0.6
--
Don Thompson
Ex ROMAD
"smeltsmoke" <no_email@please_post.net> wrote in message
news:3d4c0e66...@netnews.worldnet.att.net...
Don Thompson
Compounds of platinum:
platinum (IV) oxide peroxide
a.. Formula as commonly written: PtO3
b.. Hill system formula: O3Pt1
c.. CAS registry number: [77883-44-4]
d.. Formula weight: 243.076
e.. Class: oxide
Synonyms
a.. platinum (IV) oxide peroxide
b.. platinum oxide
c.. platinum trioxide
Physical properties
a.. Colour: golden yellow
b.. Appearance: solid
c.. Melting point: 25°C (decomposes)
d.. Boiling point:
e.. Density:
Element analysis and oxidation numbers
For each compound, and where possible, a formal oxidation number for each
element is given, but the usefulness of this number is limited, especially
so for p-block elements in particular. Based upon that oxidation number, an
electronic configuration is also given but note that for more exotic
compounds you should view this as a guide only. Element % Formal oxidation
state Formal electronic configuration
O 19.75 -1 [He].2s2.2p5
Pt 80.25 4 [Xe].4f14.5d6
--
Don Thompson
Ex ROMAD
"smeltsmoke" <no_email@please_post.net> wrote in message
news:3d4c0e66...@netnews.worldnet.att.net...
SNUMBER6
>Ain't GOOGLE wonderfull???
>
It would be a lot better if the ACS was not so protective of its journals ...
Dale A Trynor
>
> Ex ROMAD
>
> "Michael Michalchik" <micha...@aol.com> wrote in message
> news:20f4bb84.0208...@posting.google.com...
> > LOUIS <Loui...@SKYNET.be> wrote in message
> news:<3D46F493...@SKYNET.be>...
> > > N2 would explode due to strong dilatation (from -190°C to 3000°C).
> > > Never use water! but in very very large amount...tiny amounts will
> > > propagate the burning mix in all directions with tiny explosions!
> > > Carbon would be of no use since Al is much more electropositive than it,
> >
> > Though this is true, remember Le Chattliers principle, if the carbon
> > gets to the oxygen first the oxygen will be gone in the form of carbon
> > dioxide before the aluminum has a chance to get to it.
Dale Trynor wrote:
Probably a long shot but it recently occurred to me that it might be
_interesting_ to try anhydrous aluminum bromide MP 97 C, BP 268 C. Aluminum
chloride might be worth a try if you could get a eutectic as otherwise its
boiling point is below its melting point. One thing about aluminum salts is that
they are not so likely to react with the aluminum and certainly wont combust.
Would most likely make a big mess condensing on everything. Not sure but besides
toxicity they might also be like calcium chloride in that they will collect
water from the air and corrode everything, unless you wash them off surfaces
quickly.
www.alternatescience.com
Dale A Trynor
> Bill Nelson <bi...@spock.peak.org> wrote in
> news:aifvvj$3h4$2...@quark.scn.rain.com:
>
> > In alt.engr.explosives Dirk Bruere <art...@kbnet.co.uk> wrote:
> >
> >
> >> How about using MnO2 instead of FeOxide? Any idea what will happen?
> >
> > It would be a somewhat more vigorious reaction.
> >
>
> Platinum or gold oxides might be interesting. Shoudl offer even more
> energy. Or perhaps tungsten oxide, because the metal melts at high
> temperatures it could be hotter.
One of the main limitations is the rather low boiling point of aluminum
oxide. Getting a higher temperature could be perhaps helped by adding
something to increase this BP. Also dose anyone here know how well any
other metals will work in place of aluminum, such as maybe zirconium or
other uncommon.
Even magnesium oxide evaporates quite readily even without melting so its
probably also rather limited because of this.
Under pressures where boiling points are also higher one can have much
higher temperatures.
When I tried this with vanadium pentoxide, it really goes good I assume
due to its extra oxygen, but as always, one just gets more evaporated
aluminum oxide cooling the whole thing down to the same old temperature,
pity.
www.alternatescience.com
Josh Halpern
Don Thompson wrote:
> At thermite temperatures CO2 is an oxygen donor. Many a mine fire has
> occured in a CO2 rich atmosphere. The "self rescuer" that every underground
> miner carries on his equipment belt converts CO2 into CO and O2 so that the
> miner may (hopefully) reach good air in an underground fire emergency
How do they separate out the CO. On a molecule for
molecule basis CO is as bad as cyanogen. I asssume
that the CO2 is in liquid form under pressure.
josh halpern
LOUIS
Michael Michalchik wrote:
> LOUIS <Loui...@SKYNET.be> wrote in message news:<3D46F493...@SKYNET.be>...
> > N2 would explode due to strong dilatation (from -190°C to 3000°C).
> > Never use water! but in very very large amount...tiny amounts will
> > propagate the burning mix in all directions with tiny explosions!
> > Carbon would be of no use since Al is much more electropositive than it,
>
> Though this is true, remember Le Chattliers principle, if the carbon
> gets to the oxygen first the oxygen will be gone in the form of carbon
> dioxide before the aluminum has a chance to get to it. I suggested on
-Did Le Chatelier says so?
What happens to silicon oil when heated to 3000°C?
What happens to graphite at 3000°C?
Mg can burn in ice cubes of CO2 at -80°C, because of electronegativity!
Al is just the little brother of Mg!
Graphite will sure reduce the oxygen provider to metal form!
C + CuO --> CO + Cu
C + Fe2O3 --> CO + 2FeO
C + FeO --> Fe + CO
CuO + CO --> Cu + CO2
...
Then Al will react with hot CO and CO2 to give Al2O3 + C or CO!
> a couple of the other groups that a low viscosity dispersion of
> graphite in a low carbon silicone oil might work because the oil would
> seperate the particals and allow the graphite to penetrate the
> mixture, the graphite would consume oxygen without the production of
-Also have you ever seen thermite in action?
It has a relatively high speed and before someone has a chance to call for help, it
is already burned completely!
The higher the amount, the higher the heat and thus the faster the reaction
(homogeneousity, intimity of the mix is important for ignition and propagation).
A 1 liter amount burn in less than 30 sec...but remains hot quite long hence its
incendiary property!
Of course geometry of the system is important a cube will burn much faster than a
long pipe of the same volume because ignition is made by proximity!
Also one major aspect you seem to forget is:
When burning a sort of foamy crust forms on top of the thermite (dilatation of
entrapped air and solidification of Al2O3 arround) the iron or other reduced metal
being much denser agglomerates and goes to the bottom igniting unreacted powder mix
(so vertical speed is faster than horizontal speed)!
So how the hell do you expect to have the time in 30 seconds to analyse the
situation, think hey its thermite, then I'll use this kind of reactants, trow those
on top and get them to go trough the almost impermeable crust to reach the inner
igniting core of fused metal? Not a chance believe me!
Also a true terrorist would make the thing so easy for you....I guess no, under the
thermite there would be some primary explosive charge or liquified gas tank!
> much heat, CO2 would carry heat away from the reaction as would the
> decomposition and combustion of the silicone oil. All this might lower
True that reduction of metal oxides by C is endothermic; but oxydation of Al is much
more exothermic!
I have thermite at home made with extremely reactive Al powder and it can be set in
fire with a spark from a lighter; a match will do it in a second! True that with
other Al powder the initiation heat is slightly higher (200-300°C over 1600°C); so
do the math 1600 to 3000°C (will your reaction cool the mix below the 1600°C); even
in the most suitable case 2000°C to 3000°C?
Also as you would expect to extinguish the thermite fire, you would need to set it
off in all the massa, since one tiny burning spot will continue and propagate again
the fire in the massa!
> the temp enough and seperate the particals enough to interupt the
> reaction.
-In regard to what I have said earlier, no chances! Except maybe with 100 L / kg of
thermite!
> So if I wind up giving this demo to the fire department, what do you
> guys suggest I talk to them about?
>
> I am currently planning:
> Places where thermite mixtures might be found.
-In work that uses autogenic welding (railway makers, metalic structure builders,
...)
And in some kids and coolbombers basements!
Those are the most suitable places; but they are many places you don't really want
to know!
> What their legitimate and illegitimate uses are.
-legitimate use when it is used safely, can't do arm to someone or set fire to
public property or alarm neightbourghood!
Other uses are illegitimate!
> The basic chemistry and properties of the reaction.
-That's a good start indeed! When you fight, at least know what you are dealing with
sothat you can evaluate the risks, know possible evolution and what you shouldn't
ever do!
> How it can be made.
-That's not a concern to firemans! They want to set it off; they don't want pyros!
> The big don'ts with regard to thermite.
-cf supra
> How to cope with it.
-When it is not yet ignited, you can wet it next to the ignition source with water
or silicon oil (low viscosity) or dissolved in perchlorinated solvant; then ignition
will be much harder
> The ways that it could be augmented by a terrorist to make it very
> nasty.
>
-That's not a concern to firemans! They want to set it off; they don't want
terrorists!
> The demonstrations I may include are:
>
> The basic reaction
> What pre-compression does to rate of reaction.
-Almost nothing except on horizontal speed!
> What happens when you leave a penny inside a pile of thermite
> What happens when you leave a cup of water on top of a pile of
> thermite
-Depends if the cup is up or down; if the cup can withdraw the heat without breaking
and leaving the water to flow on the burning thermite!
What happens when thermite is put on an iron steel plate of 5 mm thickness!
PH Z
LOUIS
Dale A Trynor wrote:
> Dale Trynor wrote:
> What about something like ordinary salt because we are talking about such high
> temperatures it may work just like water and its evaporation will not result in
> combustion. I would imagine that its evaporation would cool I don't know how well its
> effect would be.
-Might work!But NaCl won't vapourise, you will only have heat of liquefaction!
> Zinc chloride might be worth experimenting with as it has a very low melting point
> and or with its advantage of oil or resin solubility, as used in plumbers flux.
-Might work, but as I explained somewhere else; speed of reaction and crust forming over
the thermite are two limiting factors for such external interventions!
> What might be most ideal would be some type of high temperature breakdown products
> such as produced from heating of thorium or magnesium nitrate, that would produce
> thorium or magnesium oxide. Something with this kind of an extremely high melting
> point might coat the particles inhibiting the termite reaction.
-The ignition will persue long before the MgO or ThO would melt and coat the already
burned Al!
Also Mg(NO3)2 and Th(NO3)2 are strong oxydisers and good oxygen providers; they also
provide N2, N2O, NO, NO2 gas and renders the thermite pretty dissipative to the
surrounding owing to explosions!
> Just using some quick impulsive guessing and note I said _guessing_, but something
> along the lines of a 2 part liquid and or low melting point solids mix of something
> such as zinc chloride and methyl boron,( spelling? ) "I am trying to remember the
> one made by dissolving boric oxide in methyl alcohol". Could be of the sort of thing
-Methyl borate ...the methyl part is quite flamable...would you add methanol on a
burning fire? Would you add water on thermite?
H3BO3 = (HO)3B
H3BO3 + 3 CH3-OH <==> (CH3O)3B + 3 H2O
2H3BO3 --heat--> 3H2O + B2O3 (water is released)
2(CH3O)3B --heat--> B2O3 + CH2=O + (CH2)n (flamable gas are released)
> worth experimenting with, assuming that a zinc borate, could be made to quickly form
> and would have a high melting point etc.
-Also B2O3 must be reduceable by Al!
Fe has electronegativity of 1,8!
Cu has electronegativity of 1,9!
Si has elctronegativity of 1,8!
B has electronegativity of 2!
So you must expect that all oxides of those are reduceable by Al and are thus potent
oxidisers!
Thus no way FeO, Fe2O3, Fe3O4, Cu2O, CuO, SiO2, B2O3 will really stop Al from burning!
Just for the fun of it:
C has electronegativity of 2,5!
S has electronegativity of 2,5!
So CO, CO2, carbonates are not suitable neither; I don't forget SO2, SO3 and the
infamous sulfates (CaSO4, Na2SO4 and BaSO4 have been reported in some explosions with Al
powder...)
Mn has electronegativity of 1,5 and stil Mn oxydes are reduced by Al in thermite like
process!
So does Cr with an electronegativity of 1,6!
So you need oxydes or chlorides of Li,Na,K,Mg,Ca,Sr,Ba!!!!!Because all have lower
electronegativity than Al!
> If I spent some time I could probably come up with hundreds of possible experiments
> of this sort and most, such as the suggestion above, would not work. I was just
> starting to get some ideas about using titanium tetrachloride as it will rapidly form
> an oxide and is used in sky writing for this reason but what else would the other
> component be besides ammonium hydroxide, maybe an organic.
-TiCl4 is a strong oxydiser and low volatility boiling liquid (quite toxic due to HCl
fumes)!
NH4OH is actually NH3 35% by weight in WATER!!! (toxic gas too and endothermic so
explosive)
NH3 --> 1/2N2 + 3/2H2 (fuel) + heat
> > So if I wind up giving this demo to the fire department, what do you
> > guys suggest I talk to them about?
> >
> > I am currently planning:
> > Places where thermite mixtures might be found.
> > What their legitimate and illegitimate uses are.
>
> Welding rebar in construction use for one.
>
> > The basic chemistry and properties of the reaction.
> > How it can be made.
> > The big don'ts with regard to thermite.
> > How to cope with it.
> > The ways that it could be augmented by a terrorist to make it very
> > nasty.
>
> Add mercury its salts, or other toxics that evaporate.
-And kill all the audiance!
> > The demonstrations I may include are:
> >
> > The basic reaction
> > What pre-compression does to rate of reaction.
> > What happens when you leave a penny inside a pile of thermite
> > What happens when you leave a cup of water on top of a pile of
> > thermite
>
> Don't forget other types of mixes such as copper oxide with aluminum. I don't know if
> other metals than aluminum will work but if one could get a termite reaction where
> the byproducts have higher boiling points you should have something quite impressive.
> Aluminum oxide boils at a little above 2000 C so it cant get much hotter. Underwater
-For informational purpose: Al2O3 starts to MELT at 2100°C otherwise, I wouldn't have
that much trouble to make rubies and sapphires with my 2800°C blow torch.You must
confuse Al with its oxide: Al boils at 2467°C!
I think you must go higher than 4500°C to sublimate Al2O3!
> where you have pressure would enable much higher temperatures as the boiling points
> are increased.
-Really?You mean supercritical Al2O3 or metals?
> I remember seeing photos of a type of rod that I believe was termite based that was
> used to cut through concrete or some thing similar, wish I could remember the details
> for you.
> www.alternatescience.com
-It was Al alloy pipe with pure oxygen flow in the middle that heats up to 3500°C for a
little period of time!
PH Z
LOUIS
its low acidity constant!
Same case is observed for nitrous acid that forms ester very fast vs its
brother nitric acid that is much stronger than him!
Solubility must no be that high; but it will dissolve little by little as
the ester forms!
Dirk Bruere wrote:
> "Dale A Trynor" <da...@nbnet.nb.ca> wrote in message
> news:3D4A6979...@nbnet.nb.ca...
> > Michael Michalchik wrote:
> > such as zinc chloride and methyl boron,( spelling? ) "I am trying to
> remember the
> > one made by dissolving boric oxide in methyl alcohol". Could be of the
> sort of thing
>
> Does BO dissolve in meth?
>
> Dirk
Dale A Trynor
> Dale A Trynor wrote:
>
> > Dale Trynor wrote:
> > What about something like ordinary salt because we are talking about such high
> > temperatures it may work just like water and its evaporation will not result in
> > combustion. I would imagine that its evaporation would cool I don't know how well its
> > effect would be.
>
> -Might work!But NaCl won't vapourise, you will only have heat of liquefaction!
>
> > Zinc chloride might be worth experimenting with as it has a very low melting point
> > and or with its advantage of oil or resin solubility, as used in plumbers flux.
>
> -Might work, but as I explained somewhere else; speed of reaction and crust forming over
> the thermite are two limiting factors for such external interventions!
Good point about the crust as this would mean that one might need some sort of injector. I
just recently added another posts asking if anhydrous aluminum bromide would work as a
coolant.
> -The ignition will persue long before the MgO or ThO would melt
Not so likely to melt as these oxides have rather high melting points, but why bother if the
only way to get then into the mix is as nitrates that would only aggravate the reaction.
They also might melt because of the fused aluminum oxide dissolving them. Thorium oxide was
coated onto tungsten light bulb filaments and other high temperature uses.
> and coat the already
> burned Al!
> Also Mg(NO3)2 and Th(NO3)2 are strong oxydisers and good oxygen providers; they also
> provide N2, N2O, NO, NO2 gas and renders the thermite pretty dissipative to the
> surrounding owing to explosions!
>
> -Also B2O3 must be reduceable by Al!
Tried reducing boron, it worked but didn't give me a very vigorous reaction, maybe I did it
wrong or its just not a very energetic reaction.
>
>
> So you need oxydes or chlorides of Li,Na,K,Mg,Ca,Sr,Ba!!!!!Because all have lower
> electronegativity than Al!
Or just use aluminum salts.
[snip]
>
> -For informational purpose: Al2O3 starts to MELT at 2100°C otherwise, I wouldn't have
> that much trouble to make rubies and sapphires with my 2800°C blow torch.
I always wanted to try making gemstones with thermite type reactions. I am guessing that if
I had enough and could slow the cooling by a sufficient amount one might get something.
Making ones own volcano has got to have some interesting potentials for the hobbyist
pressuring the creation of gems using different mixes. I remember reading in one of your
post that you managed to do this somehow. Like to see you write this up for a web site for
us.
> You must
> confuse Al with its oxide: Al boils at 2467°C!
> I think you must go higher than 4500°C to sublimate Al2O3!
BP 2210 C according to my handbook. Wonder if beryllium would work as its oxide melts at
2585 and boils at 3900 C.
>
> -It was Al alloy pipe with pure oxygen flow in the middle that heats up to 3500°C for a
> little period of time!
>
> PH Z
Thanks I wanted to know that.
www.alternatescience.com
LOUIS
Dale A Trynor wrote:
> Good point about the crust as this would mean that one might need some sort of injector. I
> just recently added another posts asking if anhydrous aluminum bromide would work as a
> coolant.
-Possible! But I wonder if Al halides that are really strong oxydiser and halogenating
compounds will not react with the non Aluminium moity?
2Al + 2Fe2O3 +2AlBr3--> 2Al2O3 + 2Fe + 2FeBr3
> > -The ignition will persue long before the MgO or ThO would melt
> Not so likely to melt as these oxides have rather high melting points, but why bother if the
> only way to get then into the mix is as nitrates that would only aggravate the reaction.
> They also might melt because of the fused aluminum oxide dissolving them. Thorium oxide was
> coated onto tungsten light bulb filaments and other high temperature uses.
>
> > -Also B2O3 must be reduceable by Al!
> Tried reducing boron, it worked but didn't give me a very vigorous reaction, maybe I did it
> wrong or its just not a very energetic reaction.
-The reaction is said energetic and even explosive with dry H3BO3; but I tried and got nothing
interesting...my guess is that the amount was too tiny (in my case), not hot enough, and the Al
powder not of the good type!
The reaction is violent because:
2Al + 2H3BO3 --> 3H2O + Al2O3 + 2B
B boils at 2550°C and oxydises in air with a high energy release!
Al + 3H2O -over 200°C-> Al(OH)3 + 3/2H2 + heat
H2 + 1/2O2 --> H2O
> > So you need oxydes or chlorides of Li,Na,K,Mg,Ca,Sr,Ba!!!!!Because all have lower
> > electronegativity than Al!
> Or just use aluminum salts.
-I think halides of Al or Al oxyde, but never sulfates, carbonates, borates, phosphates,
arsenates.
>> -For informational purpose: Al2O3 starts to MELT at 2100°C otherwise, I wouldn't have
>> that much trouble to make rubies and sapphires with my 2800°C blow torch.
> I always wanted to try making gemstones with thermite type reactions. I am guessing that if
> I had enough and could slow the cooling by a sufficient amount one might get something.
-Yep, but it is hard to separate or isolate the pure pregemstone mix of Al2O3 + colourisers
from the black Al2O3 crust and metal cores!
I assume to get something, one would have to handle large amounts of thermite in an insulating
heat resistant furnace!
Best way is to use solar energy and mirrors (solar lasers).
> Making ones own volcano has got to have some interesting potentials for the hobbyist
> pressuring the creation of gems using different mixes. I remember reading in one of your
> post that you managed to do this somehow. Like to see you write this up for a web site for
> us.
-Another good way is via blow torch but you get only tiny gems and they are contaminated by CO2
and combustion residue (C dust).
> > You must confuse Al with its oxide: Al boils at 2467°C!
> > I think you must go higher than 4500°C to sublimate Al2O3!
>
> BP 2210 C according to my handbook. Wonder if beryllium would work as its oxide melts at
> 2585 and boils at 3900 C.
-Believe me Al2O3 is not volatile at 3000°C!
PH Z
Bill Nelson
>>
> I think that the idea should be to get a phase change at as high a
> temperature as possible without contributing energy to increase the
> temperature. In general trend, the higher the transition temperature, the
> more heat is absorbed by the phase transition. Entropy change is about the
> same for any transition, so that the higher the temperature, the more heat
> is absorbed. Thus, another candidate may be alumina or magnesia. How about
> thorium carbonate? Dang the expense.
One compound that would not add much, if anything, to the reaction, would
be the oxide product of the Thermite reaction - Al2O3.
But the most it could do is reduce the temperature of the reacting
material - and I doubt if anyone could get close enough to dump it on
the reactants.
As others have stated, the best procedure is to let the reaction
complete - then handle any fires etc that were created by the heat
of the reaction.
--
Bill Nelson (bi...@peak.org)