shooter3
January 8th, 2007, 10:57 PM
Sorry for the long article. The link was long and wouldn't copy correctly, but this is obviously useful information.
SAFETY OF COPPER/BRASS SCREENS WITH CHLORATE COMPOSITIONS
By
The WiZ (donald j haarmann)
(The following article was in response to Ed Raszkowski's Question in PGI
Bulletin No. 38.)
Dr. McLain and Donald Lewis; Effects of Phase Change in Solid-Solid
Reactions-1966, [my copy courtesy of E.R.], determined that when a
mixture of potassium chlorate was doped with copper chlorate, and then
ground with purified sulfur [a brave move], the mixture detonated
spontaneously after being let stand undisturbed on a shelf for only thirty
minutes! The experiment was repeated using the same components,
simply placed in a plastic vial and mixed by "tumbling the vial
approximately ten minutes about its major axes." After approximately
twenty-four hours of standing behind a barricade, a similar detonation
occurred. [A less complete discussion of this work is reported in Dr.
Milan’s book; pg. 78.]
They concluded as a result of these experiments that; "Aside from the
spectacular, the finding that a potassium chlorate could be made which
when ;nixed with sulfur is spontaneously detonable at room temperature
there is a byproduct(s) of this experiment."
The doctrine of using brass, bronze or copper screens, tools and jigs for
pyrotechnic mixing and loading for non-sparking properties certainly
needs to be reexamined in light of these findings. Emphasis added]
The warning is repeated by Ellern.
J.C. Shumacher; Perchlorates: Their Properties, Manufacture and Use;
page 206+ff reports that the "***decomposition [of ammonium perchlorate]
was strongly catalyzed by powdered copper metal or cupric oxide, and to
a lesser extent by sodium chlorate, lithium or potassium dichromate."
"emphasis added]
even more importantly he states on page 215:
For example a number of fires in the drying and packaging equipment of
the AMMONIUM perchlorate plant of Western Electrochemical Company
(now American Potash dc Chemical Corporation) were found to have
been caused when the perchlorate crystals came into contact with copper
tubing in the vibrating pan-dryer heat exchanger. When stainless steel
was substituted for copper the fires ceased. Ammonium perchlorate was
found to be most sensitive to ignition at a moisture content of 0.02 to 0.5
per cent, [how dry are your stars?], particularly when it is contaminated
with copper and possibly in the presence of other metallic contaminants.
This experience confirms other reports of the accelerating effect of copper
on the thermal decomposition of ammonium perchlorate, and pyridine
perchlorate. [Emphasis added.]
The development of cheap electricity during the later part of the 19th
century, was followed by the first commercial electrolysis of chloride
solutions for the production of sodium chlorate by the French in 1866. As
a result of this process large amounts of chlorates became available at
reasonable cost. It soon followed that because chlorate mixtures had "at
all times fascinated inventors on account of the large amount of oxygen
stored up in *** chlorate(s), which can be given off so readily," these
cheap and readably available chlorates (sodium, potassium, ammonium)
were soon used for the production of explosives. In 1890, electrolysis of
sodium chlorate, lead to the production of potassium and ammonium
Perchlorates for use in the production of explosives. Although few of these
chlorate/perchlorate based explosives ever found favor in this country,
they were widely used i!1 Europe. Their use having in all cases been
supplanted by the introduction of ammonium nitrate based blasting
agents.
Because of an increasing number of accidents resulting from the use of
chlorate explosives, the US Bureau of Mines performed "Frictional Impact"
testing of chlorate explosives between September, 1911 and February 1,
1919. [Why they took eight years to complete these tests is not recorded!]
The results were reported in: Bureau of Mines; Tech. Paper 234, 1919.
Investigated was: "A certain potassium chlorate explosive that is used in
the United States and is designated Chlorate Explosive B." [Potassium
chlorate, sugar, gum arable]. The mixture had come under suspicion
because a number of premature explosions had occurred during its use in
bituminous coal mines. Quoted from the report are the following
examples:
1. "While inserting copper needle in a charge *** the charge exploded."
2. "The charge exploded while the copper needle was being inserted in
the charge bore hole."
3. "While pushing a 12-inch cartridge into bore hole, with copper needle
inserted about 6 inches in it, *** charge exploded."
They felt that: In view of the frequency of these accidents and the
seeming ease with which they took place, not being explainable by the
sensitiveness of the explosive itself to friction, it was considered advisable
to determine, if possible, the cause of the excessive sensitiveness to
friction.
It was thought, as practically all bituminous coals contain pyrite, perhaps
the pyrite was the cause of the accidents. [Now time out for a little
mineralogy -- Pyrite or "Fools Gold" is iron-sulfide (FeS2), it can with time
break down to form, iron oxide and sulfur. Its cousin Marcasite also FeS2
decomposes rather easily into ferrous sulfate and sulfuric acid!]
To the explosive B mixture was added coal dust (basically carbon, and
generally not considered safe with potassium chlorate, by most pyros) and
finely ground pyrite. ¢/hen the mixture was stirred with a copper needle it
ignited! Unfortunately the paper does not report any tests performed on
explosive "8" without the added pyrite/coal dust, with a copper wire.
"Pendulum friction" tests, were also performed, [This test was developed
to replace the then standard "broomstick" test i.e. beat on a sample of the
explosive with a broomstick and if it fails to detonate, or crack when tested
repeatedly, it receives a passing grade!] on various chlorate explosives,
ever they failed to repeat the same tests with either pyrite and/or coal add-
ed, and then compare the results. Despite these shortcomings it was
concluded that the detonation of the explosive was due to the increase in
"Friction Sensitivity" as a result of the added pyrite. In light of current
information it would appear that the real cause of the premature ignition
may have been the copper wire!
Due to shortages of raw materials during WW II, large amounts of
chlorates and Perchlorates were produced. As a result the US Bureau of
Mines felt that at war's end: "Promoters may seek to market explosives
containing these ingredients, ***" Therefore in December 1945, they
issued Information Circular #7340; Hazards from Chlorates and
Perchlorates in Mixtures with Reducing Materials.
One part of this report is of interest. Due to a fatal accident that occurred
during the manufacture of practice land mines. A sample of the material
[ingredients not stated, other than the fact that it contained potassium n
perchlorate, possible the military potassium perchlorate, barium nitrate,
aluminum flash mixture.] was tested in a "pressure friction apparatus."
The test: consists essentially of a cylindrical brass plunger that exerts a fixed
pressure and rotates at a fixed speed upon a small weight of the sample
contained in a brass cup. Only materials exceedingly sensitive to friction,
such as the initiating explosives, will fire in this test. The mixture ignited
during the test and was found to have a friction sensitivity slightly less
than that of mercury fulminate. [Emphasis added.]
Once again the source of ignition may have been copper ions from the
brass!
Although hard evidence is lacking, it would seem certain that careful pyros
will avoid using copper dust, in any of their comps. And will refrain from
using copper/brass screens when processing mixtures containing
chlorates if not Perchlorates. In the older literature there can be found
stars made using combinations of potassium chlorate, and sulfur, along
with various copper salts (copper sulfate, etc.) these are not
recommended for use, as even then they had a bad reputation.
"Mixtures containing Sulphur and a Chlorate, Black oxide of Copper or
Sulphide of Copper (and probable all Sulphides and Sulphites) with
chlorate should be avoided. Purple fires which generally contain one of
the above compounds of Copper have an especially bad name for going
off spontaneously." - C.T. Brock, 1872.
SAFETY OF COPPER/BRASS SCREENS WITH CHLORATE COMPOSITIONS
By
The WiZ (donald j haarmann)
(The following article was in response to Ed Raszkowski's Question in PGI
Bulletin No. 38.)
Dr. McLain and Donald Lewis; Effects of Phase Change in Solid-Solid
Reactions-1966, [my copy courtesy of E.R.], determined that when a
mixture of potassium chlorate was doped with copper chlorate, and then
ground with purified sulfur [a brave move], the mixture detonated
spontaneously after being let stand undisturbed on a shelf for only thirty
minutes! The experiment was repeated using the same components,
simply placed in a plastic vial and mixed by "tumbling the vial
approximately ten minutes about its major axes." After approximately
twenty-four hours of standing behind a barricade, a similar detonation
occurred. [A less complete discussion of this work is reported in Dr.
Milan’s book; pg. 78.]
They concluded as a result of these experiments that; "Aside from the
spectacular, the finding that a potassium chlorate could be made which
when ;nixed with sulfur is spontaneously detonable at room temperature
there is a byproduct(s) of this experiment."
The doctrine of using brass, bronze or copper screens, tools and jigs for
pyrotechnic mixing and loading for non-sparking properties certainly
needs to be reexamined in light of these findings. Emphasis added]
The warning is repeated by Ellern.
J.C. Shumacher; Perchlorates: Their Properties, Manufacture and Use;
page 206+ff reports that the "***decomposition [of ammonium perchlorate]
was strongly catalyzed by powdered copper metal or cupric oxide, and to
a lesser extent by sodium chlorate, lithium or potassium dichromate."
"emphasis added]
even more importantly he states on page 215:
For example a number of fires in the drying and packaging equipment of
the AMMONIUM perchlorate plant of Western Electrochemical Company
(now American Potash dc Chemical Corporation) were found to have
been caused when the perchlorate crystals came into contact with copper
tubing in the vibrating pan-dryer heat exchanger. When stainless steel
was substituted for copper the fires ceased. Ammonium perchlorate was
found to be most sensitive to ignition at a moisture content of 0.02 to 0.5
per cent, [how dry are your stars?], particularly when it is contaminated
with copper and possibly in the presence of other metallic contaminants.
This experience confirms other reports of the accelerating effect of copper
on the thermal decomposition of ammonium perchlorate, and pyridine
perchlorate. [Emphasis added.]
The development of cheap electricity during the later part of the 19th
century, was followed by the first commercial electrolysis of chloride
solutions for the production of sodium chlorate by the French in 1866. As
a result of this process large amounts of chlorates became available at
reasonable cost. It soon followed that because chlorate mixtures had "at
all times fascinated inventors on account of the large amount of oxygen
stored up in *** chlorate(s), which can be given off so readily," these
cheap and readably available chlorates (sodium, potassium, ammonium)
were soon used for the production of explosives. In 1890, electrolysis of
sodium chlorate, lead to the production of potassium and ammonium
Perchlorates for use in the production of explosives. Although few of these
chlorate/perchlorate based explosives ever found favor in this country,
they were widely used i!1 Europe. Their use having in all cases been
supplanted by the introduction of ammonium nitrate based blasting
agents.
Because of an increasing number of accidents resulting from the use of
chlorate explosives, the US Bureau of Mines performed "Frictional Impact"
testing of chlorate explosives between September, 1911 and February 1,
1919. [Why they took eight years to complete these tests is not recorded!]
The results were reported in: Bureau of Mines; Tech. Paper 234, 1919.
Investigated was: "A certain potassium chlorate explosive that is used in
the United States and is designated Chlorate Explosive B." [Potassium
chlorate, sugar, gum arable]. The mixture had come under suspicion
because a number of premature explosions had occurred during its use in
bituminous coal mines. Quoted from the report are the following
examples:
1. "While inserting copper needle in a charge *** the charge exploded."
2. "The charge exploded while the copper needle was being inserted in
the charge bore hole."
3. "While pushing a 12-inch cartridge into bore hole, with copper needle
inserted about 6 inches in it, *** charge exploded."
They felt that: In view of the frequency of these accidents and the
seeming ease with which they took place, not being explainable by the
sensitiveness of the explosive itself to friction, it was considered advisable
to determine, if possible, the cause of the excessive sensitiveness to
friction.
It was thought, as practically all bituminous coals contain pyrite, perhaps
the pyrite was the cause of the accidents. [Now time out for a little
mineralogy -- Pyrite or "Fools Gold" is iron-sulfide (FeS2), it can with time
break down to form, iron oxide and sulfur. Its cousin Marcasite also FeS2
decomposes rather easily into ferrous sulfate and sulfuric acid!]
To the explosive B mixture was added coal dust (basically carbon, and
generally not considered safe with potassium chlorate, by most pyros) and
finely ground pyrite. ¢/hen the mixture was stirred with a copper needle it
ignited! Unfortunately the paper does not report any tests performed on
explosive "8" without the added pyrite/coal dust, with a copper wire.
"Pendulum friction" tests, were also performed, [This test was developed
to replace the then standard "broomstick" test i.e. beat on a sample of the
explosive with a broomstick and if it fails to detonate, or crack when tested
repeatedly, it receives a passing grade!] on various chlorate explosives,
ever they failed to repeat the same tests with either pyrite and/or coal add-
ed, and then compare the results. Despite these shortcomings it was
concluded that the detonation of the explosive was due to the increase in
"Friction Sensitivity" as a result of the added pyrite. In light of current
information it would appear that the real cause of the premature ignition
may have been the copper wire!
Due to shortages of raw materials during WW II, large amounts of
chlorates and Perchlorates were produced. As a result the US Bureau of
Mines felt that at war's end: "Promoters may seek to market explosives
containing these ingredients, ***" Therefore in December 1945, they
issued Information Circular #7340; Hazards from Chlorates and
Perchlorates in Mixtures with Reducing Materials.
One part of this report is of interest. Due to a fatal accident that occurred
during the manufacture of practice land mines. A sample of the material
[ingredients not stated, other than the fact that it contained potassium n
perchlorate, possible the military potassium perchlorate, barium nitrate,
aluminum flash mixture.] was tested in a "pressure friction apparatus."
The test: consists essentially of a cylindrical brass plunger that exerts a fixed
pressure and rotates at a fixed speed upon a small weight of the sample
contained in a brass cup. Only materials exceedingly sensitive to friction,
such as the initiating explosives, will fire in this test. The mixture ignited
during the test and was found to have a friction sensitivity slightly less
than that of mercury fulminate. [Emphasis added.]
Once again the source of ignition may have been copper ions from the
brass!
Although hard evidence is lacking, it would seem certain that careful pyros
will avoid using copper dust, in any of their comps. And will refrain from
using copper/brass screens when processing mixtures containing
chlorates if not Perchlorates. In the older literature there can be found
stars made using combinations of potassium chlorate, and sulfur, along
with various copper salts (copper sulfate, etc.) these are not
recommended for use, as even then they had a bad reputation.
"Mixtures containing Sulphur and a Chlorate, Black oxide of Copper or
Sulphide of Copper (and probable all Sulphides and Sulphites) with
chlorate should be avoided. Purple fires which generally contain one of
the above compounds of Copper have an especially bad name for going
off spontaneously." - C.T. Brock, 1872.