Pyrotechnic Ingredients

Annual Proceedings of the Safety Seminars, Dept, of Defense, Explosive Safety Board, Washington, D.C. International symposia on explosives and closely related subjects are excellent sources of information, ie, international symposia on detonation symposia on combustion symposia on chemical problems connected with the stabiUty of explosives international pyrotechnics seminars symposia on compatibiUty of plastics and other materials with explosives, propellants, and pyrotechnics, and processing of explosives, propellants, and ingredients and symposia on explosives and pyrotechnics Mineral Industy Surveys, U.S. Bureau of Mines, Pittsburgh, Pa. Periodic pubhcations dedicated primarily to explosive studies in Propellants and Explosives Journal of Ha yardous Materials, and apparent consumption of industrial explosives and blasting agents in the United States. 

Proceedings of the Symposia on Compatibility of Plastics and Other Materials with Explosives, Propellants and Pyrotechnics and Processing of Propellants, Explosives, and Ingredients, ADPA, Washiagton, D.C. 

Despite shortcomings, the Micromerograph in the early 1960 s was the only instrument generally available for determining particle size distribution of sub-sieve pro pint and pyrotechnic ingredients. 

Red P has been employed as an ingredient of pyrotechnic smoke, delay and safety match formulations (Refs 1,2,3 4). White smoke consisting of small droplets of phosphoric acid have been widely used for military purposes. 

Pulverin. French for meal powder. A special, finely pulverized BlkPdr consisting of K nitrate 75, S 12.5 and charcoal 12.5%, prepd by rolling the ingredients with Pb or lignum vitae balls in a hardwood barrel. It has been used in pyrotechnic applications... 

Photo flash powders are loose mixts of powdered oxidizers such as Ba nitrate and K perchlorates with metallic fuels, principally Mg, A1 and Zr. These ingredients have such small particle sizes that they bum with expl violence for durations of less than 0.1 sec. At present photoflash powders are used exclusively in military aerial photography, whereas civilian applications are served by electrically ignited Zr or Hf wire containing flashbulbs. Since 1970. non-electric, pyrotechnically functioned, flash cubes have appeared on the market (USPs 3535063,3540813 3674411)... 

A pyrotechnic mixture containing the powdered ingredients was found dangerously sensitive to frictional initiation and highly explosive. 

A. P. Chafln, S. L. Christian, R. A. Hollins, A. T. Nielsen and W. P. Norris, Energetic Materials Research at NWC , Proc. ADPA Meetings on Compatibility of Plastics and Other Materials with Explosives, Propellants, Pyrotechnics and Processing of Explosives, Propellants and Ingredients, Long Beach, CA, 1986, 122-125. 

Propellants, Pyrotechnics and Processing of Explosives, Propellants and Ingredients, San Diego, CA, 62-68 (1991). 

Though the oxidation potentials of potassium nitrate (KN KNO3) and sodium nitrate (SN NaN03) are high, both metal nitrates generate combustion products of high Mg, Thus, the specific impulse becomes low when KN or SN is used in a rocket propellant KN and SN are used as major ingredients of explosives and in pyrotechnics. KN is a weU-known material as a major component of black powder. 

Fedotova, T. D., Glotov, O. G., and Zarko, V. E., Ghemical Analysis of Aluminum as a Propellant Ingredient and Determination of Aluminum and Aluminum Nitride in Gondensed Gombustion Products, Propellants, Explosives, Pyrotechnics, Vol. 25, 2000, pp. 325-332. 

Table 1.2 lists the current applications of black powder. In general, as the balance of the ingredients in the composition shifts from the near stoichiometric 75 15 10 mix, the rate of burning decreases but is still fast enough to be of major importance in hrework rockets, delay fuses, igniters and pyrotechnic smokes. 

Charcoal is used as a fuel and burning rate stabiliser while dextrin (starch gum) forms a viscous dispersion in water such that it can be added to the pyrotechnic ingredients to form a slurry that will adhere to the wires when dipped. It is normally necessary to dip the wires several times in order to build up a satisfactory coating before drying in a current of warm air. 

The active ingredients in pyrotechnic whistle compositions are invariably based on aromatic compounds such as gallic acid (10.1) or the salts of aromatic acids including sodium salicylate (10.2) and potassium benzoate (10.3). 

ILL The apparatus for reducing the particle size of pyrotechnic ingredients and/or intimately mixing the said ingredients. 

Of all the improvised explosives the author has made, HMTD probably has the simplest preparation. It requires three basic ingredients hexamethylene tetramine (hexamine), citric acid, and hydrogen peroxide. Hexamine is a common fuel used in the pyrotechnic industry and can be purchased from numerous chemical supply houses. It is also the principle ingredient used by many camping stoves and can be purchased in tablet form for this purpose. Citric acid is a common flavorant additive and can be purchased from many drugstores. Aqueous hydrogen peroxide availability was discussed earlier. 

As mentioned earlier, chlorates are also a major ingredient in various pyrotechnic formulations. Typically potassium chlorate is utilized in this capacity due to the more hygroscopic nature of the sodium analog. Mixed with powdered aluminum and/or sulfur, potassium chlorate produces a mixture commonly referred... 

Particle size of ingredients Homogeneity, and pyrotechnic performance, will increase as the particle size of the various components is decreased. The finer the particle... 

Pyrodex" is a patented pyrotechnic composition designed to fulfill many of the funetions of blaek powder. It eontains the three ingredients found in blaek powder plus binders and burning rate modifiers that make the material somewhat less sensitive and slower burning. A greater degree of confinement is required to obtain performance comparable to "normal" black powder [6]. 

The oldest and still widely used in pyrotechnics and fireworks "first fire" and "starter" mixture is BkPdr. It belongs to mixts without metallic ingredients. Metallic mixts contain combustible powdered metals, such as Mg, Al, Zr etc. Metalloids B and Si are considered metallic fuels because of their similarity in pyrochemical behavior to metals. Although BkPdrs are described in Vol 2 of Encycl, pp Bl65ff, we are giving here as Table E compns of three formulations used in pyrotechnics, as described by Ellern (Ref 57, p 375)... 

K chlorate, Sb sulfide TNT and MF, Sb sulfide, Ba nitrate, PA glass 524-35 (Analyses of pyrotechnic compositions and of their ingredients) ... 

Critical Relative Humidities for Some Explosives and for Ingredients of Explosive and Pyrotechnic Compositions... 

Figure A.23 Ammonium nitrate low explosive, pyrotechnic ingredient, oxidizer.

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