Smoke Mixtures

The generation of colored smoke by the volatilization of an organic dye is a fascinating pyrotechnic problem. The military and the fireworks and entertainment industries rely on this technique for the generation of copious quantities of brilliant colored smoke. The requirements for an effective colored smoke composition include  

The mixture must produce sufficient heat to vaporize the dye, as weU as a sufficient volume of gas to disperse the dye into the surrounding space. 

The mixture must ignite as a low temperature and continue to bum smoothly at low temperature (well below 1,000°C). If the tanperature is too high, the dye molecules will decompose, and the color quality as weU as volume of the smoke will deteriorate. Metal fuels are not used in colored smoke mixtures because of the high reaction temperatures they produce. 

The molecules creating the colored smoke must be of low toxicity (including low carcinogenicity). Further, they must readily sublime without decomposition at the temperature of the pyrotechnic reaction to yield a dense smoke of good color quality.  

The ratio of oxidizer to fuel will also affect the amount of heat and gas that is produced. A stoichiometric mixture of KCIO3 and sulfur (Equation [9.1]) contains a 2.55 1 ratio of oxidizer to fuel, by weight. Colored smoke mixtures in use today contain ratios very close to this stoichiometric amount. The chlorate-sulfur reaction is not strongly exothermic, and a stoichiometric mixture is needed to generate the heat necessary to volatilize the dye. 

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Another type of smoke mixture, a volatile hygroscopic chloride for thermal generation, has the U.S. Army designation HC, type C. It is composed of ca 6.7 wt % grained aluminum, 46.7 wt % zinc oxide ZnO, and 46.7 wt % hexachloroethane [67-72-17, The ratio of zinc oxide to... 

Marijuana is the name given to the dried leaves and flower heads of the hemp plant, Cannabis sativa, prepared as a smoking mixture. 

Red Phosphorus smoke mix production. Evaluation of the Sprout Waldron 35 cubic foot Jet Airmix unit for production of Red Phosphorus (RP) M8E1 Smoke Mixtures was conducted (12). Results indicated the mix was stabile and not easily initiated by heat, but sensitive to friction and snark stimuli. The burning time was slow with dense smoke emission. 

Siegel, R. K., Collings, P. R., and Diaz, J. L. (1977) On the use of Tagetes lucida and Nicotiana rustica as a Huichol smoking mixture The Aztec Yahutli with suggestive hallucinogenic effects. Economic Botany, 31 16-23. 

Henry MC, Barkley JJ, Rowlett CD. 1981. Mammalian toxicologic evaluation of hexachloroethane smoke mixture and red phosphorus. Frederick, MD U.S. Army Medical Bioengineering Research and Development Laboratory. Final Report. ADA 1095 83. 

We all drank the ayahuasca. The taste was sharp and astringent, like a sauce of leather and mole, but it faded quickly as the liquid went churning through our guts. Dennis took only one more mushroom to help him hear the tone. The darkness outside was utter and we had no clock it seemed hours since Dave and Vanessa had left us. All was finally in readiness the living mushroom, the harmine brew, and a harmine smoking mixture, "just in case." After we each had about a half-cup of the ayahuasca infusion, we settled down to wait. 

The use of sulfur as a fuel in pyrotechnic compositions dates back over one thousand years, and the material remains a widely-used component in black powder, colored smoke mixtures, and fireworks compositions. For pyrotechnic purposes, the material termed "flour of sulfur" that has been crystallized from molten sulfur is preferred. Sulfur purified by sublimation - termed "flowers of sulfur" - often contains significant amounts of oxidized, acidic impurities and can be quite hazardous in high-energy mixtures, especially those containing a chlorate oxidizer [11]. 

A variety of dyes have been used in colored smoke mixtures many of these dyes are presently under investigation for carcinogenicity and other potential health hazards because of their molecular similarity to known "problem" compounds [4]. The materials that work best in colored smokes have several properties in common, including... 

Structures for some of the dyes used in colored smoke mixtures are given in Table 8.3. 

Colored smoke mixtures also contain either sulfur or a carbohydrate as the fuel, and a volatile organic dye that sublimes from the reaction mixture to produce the colored smoke. These compositions contain a large excess of potential fuel, and their explosive properties are greatly diminished as a result. Smoke mixtures react with low flame temperatures (500°C or less)... 

Red phosphorus is mixed as a water slurry with potassium chlorate for use in toy caps and noisemakers. These mixtures are quite sensitive to friction, impact, and heat, and a large amount of such mixtures must never be allowed to dry out in bulk form. Red phosphorus is also used in white smoke mixtures, and several examples can be found in Chapter 8. 

Although a low ignition temperature is required, the smoke mixture must be stable during manufacturing and storage, over the expected range of ambient temperatures. 

The original HC smoke mixtures (Type A) contained zinc metal and hexachloroethane, but this composition is extremely moisture- sensitive and can ignite spontaneously if moistened. An alternative approach involves adding a small amount of aluminum metal to the composition, and zinc oxide (ZnO) is used in place of the moisture-sensitive metal. Upon ignition, a sequence of reactions ensues of the type [6]... 

In either event, the products are ZnCl 2, CO, and A12O 3 The zinc oxide cools and whitens the smoke by consuming atomic carbon in an endothermic reaction that occurs spontaneously above 1000°C (equation 8.6). The reaction with aluminum (equation 8.4 or 8.8) is quite exothermic, and this heat evolution controls the burning rate of the smoke mixture. A minimum amount of aluminum metal will yield the best white smoke. Several "HC" smoke compositions are listed in Table 8.4. 

Type 2 2-kg Target Indicator consisted of a Bakelite cylinder with round nose and tail provided with fins. The filling consisted of liquid FM (Titanium Tetrachloride). This smoke mixture was scattered when the bomb was released from a plane, hit the target and broke (pp 113-14, Fig 86)... 

Type 95 50-mm Smoke Mortar Shell was a forged steel cylinder with conical nose housing a Fuze. It contd 3.7 oz Hexachloroethane Smoke Mixture and was fired by NC-DPhA flaked proplnt.. Fired from Type 89 Grenade Discharger (pp 374—75, Fig 297)... 

Fu mi gene. Fr for a pyrotechnic smoke mixture. One of the pre-WWII French mixtures contd tetrachlorethane 40, ZnO 20, powdered Zh 15, Ca silicide 15 Na chlorate 10%... 

You now have your smoking mixture. This is a 6X enhancement i.e. theoretically the leaf material is now 6 times as strong as unenhanced leaf material, so smoke it with great care, and have a sitter present. This stuff can be very strong. 

Ital pyro compn contg pitch is the black smoke mixture K chlorate 60 Pitch 40% (Ref 6, P238)... 

Usage Dark green resin is scraped or extracted form leaves and flower parts and added to tobacco or other smoking mixtures. Dried leaves may also be smoked or chewed. 

Uses In smoke mixtures and in some permissible gelatine dynamites. See HC Mixture. 

Composition A smoke mixture containing zinc dust, hexachlorethane, ammonium perchlorate, ammonium chloride, and calcium carbonate. 

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