176
Chemistry of Pyrotechnics
Smoke and Sound
177
HC1 (gas) + NH 3 (gas) -> NH,,Cl (solid)
TABLE 8.5 "Flash and Sound" Compositionsa Similarly, titanium tetrachloride (TiC1 4) rapidly reacts with moist air to produce a heavy cloud of titanium hy-
% by
Refer-
droxide - Ti(OH)
Composition
weight
Use
ence
4 - and HC1.
I.
Potassium perchlorate,
50
Military simulator
8
KC1O,,
NOISE
Antimony sulfide,
33
Two basic audible effects are produced by explosive and pyro-Sb 2S 3
technic devices: a loud explosive noise (called a "report" or Magnesium
17
"salute" in the fireworks industry) and a whistling sound.
II. Potassium perchlorate,
64
M-80 firecracker for
8
A report is produced by igniting an explosive mixture, usually KC1O,,
military training
under confinement in a heavy-walled cardboard tube. Potassium Aluminum
22.5
chlorate and potassium perchlorate are the most commonly used Sulfur
10
oxidizers for report composi
s , which are also referred to as
Antimony sulfide,
3.5
"flash and sound" mixtures.
hese mixtures produce a flash of
Sb 2S 3
light and a loud "bang" upon ignition. Black powder under substantial confinement also produces a report.
III. Potassium chlorate,
43
Japanese "flash thun- 5
"Flash and sound" compositions are true explosives, and they KC1O 3
der" for aerial fire-
will detonate if a sufficient quantity of powder (perhaps 100
Sulfur
26
works
Aluminum
grams or more) is present in bulk form, even if unconfined!
31
Chlorate-based mixtures are considerably more hazardous than IV. Potassium perchlorate,
50
Japanese "flash thun- 5
perchlorate compositions because of their substantially lower ig-KCIO,,
der" for aerial fire-
nition temperatures. However, flash and sound compositions Sulfur
27
works
made with either oxidizer must be considered very dangerous.
Aluminum
23
They have killed many people at fireworks manufacturing plants in the United States and abroad. Mixing should only be done using remote means, and the smallest feasible amount of com-aNote: These mixtures are explosive and very dangerous. They position should be prepared at one time. Bulk flash and sound must only be prepared by trained personnel using adequate pro-powder must never be stored anywhere near operating person-tection, and should be mixed by remote means.
nel.The famous Chinese firecracker uses a mixture of potassium chlorate, sulfur, and aluminum. The chlorate combined with sulfur makes this mixture doubly dangerous for the manufacturer.
The standard American flash and sound composition is a blend The ignition temperature of the potassium chlorate/sulfur system of potassium perchlorate, sulfur or antimony sulfide, and alu-is less than 200°C! The presence of aluminum - an excellent minum. The ignition temperature of this formulation is several fuel - guarantees that the pyrotechnic reaction will rapidly prop-hundred degrees higher than chlorate-based mixtures, but these agate once it begins. Safety data from China is unavailable, but are still very dangerous compositions because of their extreme one has to wonder how many accidents occur annually from the sensitivity to spark and flame. Ignition of a small portion of a preparation of this firecracker composition. The preparation of
"flash and sound" mixture will rapidly propagate through the en-potassium chlorate/sulfur compositions was banned in Great Britain tire sample. These mixtures should only be prepared remotely, in 1894 because of the numerous accidents associated with this mix-by experienced personnel. Table 8.5 lists several "flash and ture!
sound" formulas.
178
Chemistry of Pyrotechnics
Smoke and Sound
179
TABLE 8.6 Whistle Compositionsa
be stored near operating personnel. Several formulas for whistle compositions are given in Table 8.6.
% by
Refer-
Composition
weight
Note
ence
REFERENCES
I.
Potassium chlorate
73
Military simulator
8
KC1O