Nontoxic/Environmentally Acceptable Pyrotechnic Smokes
Journal of Scientific & Industrial Research Vol.59, June 2000, pp 455-459
Nontoxic/Environmentally Acceptable Pyrotechnic Smokes
Amarjit Singh, P J Kamale and Haridwar Singh High Energy Materials Research Laboratory, Sutarwadi, Pune 411 021
The pyrotechnic smokes have several applications, both in civil and defence fields. In the recent past, nontoxic and environmentally acceptable smokes have gained importance because of increased awareness regarding the need to have a healthy environment, free from toxic pollutants. The paper reviews nontoxic, environmentally acceptable smokes and suggests future line of work in this area.
Introduction cent and aluminium 10-20 per cent and packed in the Pyrotechnic smokes, constitute an important class in inner side of a metal cylinder with smoke generating com the field of pyrotechnics, wherein the heat of chemical position containing paraffin 15- 90 per cent, sodium bi reaction between oxidant and fuel vaporises the volatile carbonate 10-50 per cent placed in the outer side of the ingredients or the products, which subsequently condense heating agent. The Americans have produced neutral 1 3 as fine particles creating smoke - • The pyrotechnic smoke (with pH 5-7) using the smoke composition zinc smokes are used in civil and defence sectors. They are oxide 29-33 per cent, polychloroisoprene 10-17 per cent, used for signaling, screening, decoying, deceiving, and ammonium perchlorate 31-40 per cent, ammonium chlo 4 6 training purposes in the defence - . Civil applications ride 3.8- 14.3 per cent, and dioctylphthalate (plasticiser) include testing leakage in enclosed areas like boilers and 6-12 per cent. The pressed pellets were coated with a pipes, as insecticides, as a scavenging agent, for protec surface stabilising methacrylate resin and synthetic rub 13 tion of orchards from sudden temperature changes, and ber, and had a burning rate of 0.9 mrnls . Smoke pro 7 111 for putting off underground fires - • Because of in ducing liquid like titanium chloride (> 40 per cent of creased awareness and concern about the environment, total smoke charge) has been absorbed in a porous highly health and safety of living beings in recent times, many absorbent powder containing activated carbon (bulk den studies are going on in India and abroad for the develop sity< 0.7 and pore surface> 120m2/g) or volcanic ash ment of nontoxic and environmentally acceptable pyro or calcium silicate. This mixture is useful as a smoke 14 technic smokes for fire-fighting, troop training, signal charge for grenades, projectiles, rockets or bombs • ing and screening. In view of the scanty information An American patent 15 describes the nontoxic smoke available in literature, a need was felt for a review of composition useful for fire fighting training, containing the work done so far. This paper presents the survey of cinnamic acid 47.5, sucrose 12, potassium chlorate, 29, the nontoxic/environmentally acceptable pyrotechnic sodium bicarbonate 6.5, and silicon dioxide 5 wt per cent. 16 smo~e compositions. The Germans claim that a smoke composition of lower toxicity can be produced by mixing guanidine nitrate 36 Smoke Compositions per cent, hexachloroethane 34 per cent, zinc 22 per cent A nontoxic signal smoke was developed by mixing and zinc oxide 08 per cent or hexachloroethane 4 per 40-80 per cent of potassium perchlorate with 5-30 per cent, red phosphorous 56 per cent, guanidine nitrate 40 11 cent iron, silicon, magnesium or aluminium powder • per cent and believe that lower toxicity is due to A nontoxic bluish white smoke was generated by igni neutralisation of acidic products by guanidine nitrate. tion of smoke composition containing 75 parts of potas A Polish patent 17 contains 14-29 guanidine nitrate or its sium perchlorate with 22 parts of iron powder. Another amine derivatives, 24-39 ammonium perchlorate, 2-6.5 Japanese patent12 describes the smoke generator, which potassium chlorate, 0.5-2.5 potassium chromate, 23-37 produces nontoxic smoke, containing the heating agent anthracene, 5-36.5 polystyrene and 0.8 wt per cent am manganese dioxide 52-80 per cent, iron oxide 10-20 per monium chloride along with catalytic amounts of potas- 456 J SCI IND RES VOL 59 JUNE 2000
sium phosphate. The smoke generating agent is a mix and/or sodium carbonate 0-10, potassium chloride/so ture of anthracene, fine powdered polystyrene and so dium chloride 20-50 and azodicarbonamide, oxamide or dium chloride. A smoke composition containing am dicyandiamide 5-20 wt per cent. The priming composi monium chloride 50g, sugar 25 g, potassium chlorate tion for this is a mixture of magnesium powder 25, po 20 g, and alizarine dye 5g has been used for leak detec tassium nitrate 10, potassium perchlorate 10, calcium tion in chimneys and for other flow control investiga carbonate 20 and potassium chloride 10 wt per cent. tions1 8. Another Dutch patent 19 describes smoke com Uwe26 of NICO Pyrotechnic Germany, has produced a position containing ammonium chloride 56 per cent, nontoxic smoke composition called KM which contains white sugar 15 per cent, rosin 9.5 per cent, and potas potassium chloride 44 per cent, potassium perchlorate sium chlorate 19.5 per cent packed in a polyethylene 5 per cent, potassium nitrate 27 per cent, magnesium 8 bag which produces smoke that is an environmental and per cent, and azodicarbonamide (H N-CO-N =N-CO health improvement and is useful for testing leakage in NH ) 16 per cent. The aerosol genJrated contains par pressure systems. A German patent20 uses a mixture of ticiJs of sublimed potassium chloride, potassium com polyethylene glycol (average molecular weight 200-600) pounds and magnesium oxide which are nontoxic and and water in 1:9 or 9:1 volume or wt per cent ratios for have pH between 7.0- 8.0. The ignition composition smoke screens, which can be used for obscuring mili contained potassium nitrate 63 per cent and magnesium tary installations without endangering friendly person powder 23 per cent, while the booster composition con nel. Glycerine can also be used in place of polyethylene sisted of potassium nitrate, 47 per cent, calcium carbon glycol. Helbig and Anders21 have used 1,2-propanediol ate 21 per cent, and magnesium 32 per cent. It is claimed 70-90, water 10-30, ethanol 0.2 and an odor masking that a residue of only 15 per cent is obtained which con substance 0.001-0.004 vol per cent for producing white sists of potassium chloride, potassium carbonate, and theatrical stage smoke by heating and spraying the liq magnesium oxide. An American patent27 claims that uids. The Americans22 have used BAMO [3,3 bis white smoke generator for use in military screening con (azidomethyl) oxetane] as fuel for flares and colored tains terephthalic acid 35-65 wt per cent and 3,3-bis smokes, which helps in greater ship and aircraft safety. (azidomethyloxetane) energizer and produces nontoxic Swiatosz23 has described the method of generating train smoke. By thermal nebulization process, nontoxic smoke ing smoke using propylene glycol PEG 200 or PEG 200- has also been produced using 1,2 propanediollwater mix water mixture. An American patent24 claims that non ture2x . American scientists have produced nontoxic toxic smoke can be produced from a smoke composition smoke using aliphatic dicarboxylic acids, binder, oxi consisting of 1,4 benzene dicarboxylic acid 50, potas dant, fuels, and coolants. However, full details of ingre 9 sium chlorate 23, and sucrose 27 wt per cent. Another dients used are not given in this patent2 . Waltor and 30 German patent25 claims that nontoxic smoke screens Tobler , in their patent, describe an environmentally safe consisting of sodium chloride or potassium chloride par smoke generating pyrotechnic composition which uses ticles can be generated by .a composition consisting of porous carbon granules (organic reducing agents) and magnesium 10-25, potassium nitrate 20-36, potassium ammonium nitrate (inorganic oxidising agent). The perchlorate 0-15, calcium carbonate 12-20, potassium oxidising agent is bound to carbon granules by using a bicarbonate, sodium bicarbonate, potassium carbonate, polar solvent. It is also reported that the M8 smoke pot
For biodata of Dr Amarjit Singh and Mr. P J Kamale, see 1 Sci Ind Res, 57(3) ( 1998) 124.
Dr Haridwar Singh is a Director in High Energy Materils Research Laboratory (HEMRL), Pune. He obtained his Ph.D. in Solid Rocket Propellant Combustion from University of Pune. He has supervised 20 post-graduate and doctoral thesis. He was a Visiting Scientist at the Max-Plank Institute, Germany; High Pressure Combustion Laboratory, Pennsylania State Uni versity, Army Research Laboratory; Maryland Sci ence Application Centre. Santa Clara and Sandia National Laboratory, USA. He was awarded the Astro nautical Society of India Award f or the year 1994. He was conferred with the DRDO Scientist of the Year Award in 1983 and 1993 f or his contributions in applied sciences and advanced solid propellants, high energy propellants, respectively. He is the recipient of DRDO Cash Award for development ofpo wer plants for missile target and Best Paper Award of Defence Science Journal in 1984. He is the Chairman of th e High Energy Materials Society of India, a member ofAIAA , International Advisory Board-Flame Structure & Combustion, and honorary member of the Russian Academy of Astronautics. SINGH et al.: PYROTECHNIC SMOKES .457
containing benzene and formaldehyde are currently the perchlorate 20.0 per cent are potentially useful as en vi- . safest training pot used by the US Army, along with ron mentally acceptable compositions. Smoke composi 31 terephthalic acid based smoke composition . An Ameri tions, based on potassium chlorate, lactose, and 20-45 can patent claims that a smoke composition for training per cent cinnamic acid are used by the British forces for fire fighters in extinguishing fires contains ferrocene and screening, fire fighting and riot training. JY Hancox and its derivatives, along with a volatile iron compound, Murphl 0 have discussed the essential requirements of 32 which can be incorporated in the liquid hydrocarbon . the training smoke and stated that the system based on A nontoxic coloured smoke generating composition de titanium tetrachloride, flaky materials (like graphite and scribed in a Japanese patent contains sodium azide 20- iron oxide) along with pyrotechnic smokes based on 23 per cent, smoke controlling agents 5-I5 per cent, dyes white dyes (like methyl anthraquinone and 45 --55 per cent, coolants 0 - I5 per cent, and binders 0 chloroanthraquinone) as well as cinnamic acid and 3 34 - 12 per cent1 . Shidlovskiy describes another non terephthalic acid (mixed with chlorate and lactose) have toxic smoke composition based on ammonium chloride good potential for training smokes. In Australia, white and containing potassium chlorate 20-30 per cent, am smoke compositions based on terephthalic acid and cin monium chloride 50 per cent, naphthalene or anthracene namic acid are being developed for fire fighting trai ning 41 20 per cent, and wood charcoal 0 - I 0 per cent. Ammo in enclosed areas • A castable composition with burn nium chloride based nontoxic smoke composition has ing time of 5 min and mass 1.2 kg has been developed in also been developed in India and used in the training Canada, which contains cinnamic acid 50 per cent, po 35 smoke generator . tassium chlorate 23 per cent, sucrose 6 per cent, iron Amarjit Singh et al. 36 have determined theIR screen oxide 1 per cent, and binder (hydroxy terminated ing properties of a nontoxic smoke composition contain polybutadiene) 20 per cent. The combustion products 42 ing I5 per cent anthraene, 40 per cent potassium chlor from this composition have also been deterrnined . Work ate, and 45 per cent ammonium chloride in the IR win was carried out in America to replace hazardous colour dows 2-2.4 11m, 3-5 11m and 8-13 11m along with theIR dyes used in the MIS colored smokes hand grenades. emission characteristics of the smoke cloud of 4.9 11111 Vat yellow 4 and benzanthrone used in the yellow smoke and 10.6 11m . In addition the particle size of the same composition were replaced by Cl solvent yellow 33 to nontoxic smoke composition has been determined by give the yellow smoke composition containing potas Amarjit Singh et a!Y using Andersen Fractionating sam sium chlorate 22 per cent, sucrose 15 per cent, magne pler and the aerodynamic median diameter (AMD) was sium carbonate 2I per cent and CI solvent yellow 33 (42 found to be 0.82 11m while the geometric standard de per cent). Similarly, environmentally acceptable green viation (
less, or those which get decomposed subsequently into References harmless products by the action of light, water, and mi I Cackett J C, Monograph On Pyrotechnic Compositions (Royal croorganisms. Armament Research and Development Establishment, Fort Halstead, Sevenoaks, Kent, England) 1965, I. 2 Conkling J A, Chemistry of Pyrotechnics - Basic Principles Conclusions and Theory (Marcel Dekker, Inc., New Yurk and Basel) 1985, The various nontoxic, environmentally acceptable 168-176. smoke compositions can be classified under six main 3 KayeS M, Encyclopaedia ofExplosives and Related Items (US groups: Army Armament Research and Development Command, Large Calibre Weapon Systems Laboratory, Dover, New Jersey) PATR 2700, 8( NTIS ADA No.057762) 1978, p.507-508. (i) Smoke compositions generating volatile chlorides 4 Singh Amarjit, Avachat S G, & Singh Haridwar, Infrared Screen of alkali metals like sodium chloride, potassium ing Smoke- A Review, 1 Sci Ind Res, 53 (1994) 667-673. 5 Design Of Ammunition for Pyrotechnic Effects, in US Army chloride or least amount of zinc chloride1L25.26·3x. For Material Command, Engineering Design Hand Book, Military the smoke compositions producing zinc chloride the Pyrotechnic Series Part-] (AMC Pamphlet 706-185) 1967, p. threshold limit value for zinc chloride is 1.00 mg/ 7.1-7.4. m3 and the intravenous lethal dose for 50 per cent 6 Holst G C, Tactical Smokes Increases Survivability, Armor, 94 kill is 75 mg/kg, while on the other hand sodium (1984) 20-25. chloride and potassium chloride are nontoxic chemi 7 Singh Amarjit & Avachat S G, Behind the Smoke Screen, Sci Rep, 31 (No.12) (1994) 13-16. cals44-4s. 8 Ogorkiewicz R M, Countermeasures for Tanks Beating Smart (ii) Smoke compositions generating particles of alka Munition, lnt Def Rev, 22 (1989) 55. line oxides and chlorides like calcium hydroxide, 9 Singh Amarjit, Studies on Infrared Screening Smokes, PhD magnesium oxide, calcium carbonate, and ammo Thesis, University of Pune, Indi a, 1996. I 0 Ell ern Herbert, Military and Civilian Pyrotechnics (Chemical nium chloride act as nutrient for plants and are, 25 26 Publishing Company Inc., New York) 1968, 148 and 413. therefore, environmentally acceptable - . II Shigeru M, lap Pat 75, 36, 614 (to Japan Credit Co. Ltd), April (iii) Use of suitable agents for neutralisation of acidic 1975, ChemAbstr, 84 (1976) 108015g. products (like guanidine nitrate) or generation of 12 Hosoyo Fire Works Co Ltd Japan, Tokkyo Koho, l ap Pat neutral particles around pH7 like ammonium chlo 5738950 (to Japan Defence Agency Technical Research & De ride 13.16. 17-19.34-37.43.46. velopment Institute), August 1982, Chern Abstr, 98 (1983) 91992n. (iv) Use of ingredients like cinnamic acid, aliphatic di 13 Uwe Krone & Klaus Moeller, US Pat 4, 376, 001 (to Nico carboxylic acid, and terephthalic Pyrotechnics), March 1983, Chem Abstr, 98 (1983) 21 8239e. acid 12,15 ,24 ,27,29.31.3H.39,40-42. These compounds and their 14 Anderson Rolf, Brit Pat 1,302, 736 (to Lindesbergs Industri AB), January 1973, Chem Abstr, 78 (1973) 999691. salts are available in natural products, in perfumes, 15 Douda Bernard E & Tanner John E, U S Pat 4, 302, 374 (to as well as food preservatives, and are at the most United States Dept. of Navy), Chem Abstr, 84 (1977) 87246c. mild irritants47. 16 Drachauser Georg & Schiess! Alois, Ger Pat 2, 819, 850 (to Buck Chemisch-Technische Werke G m b H and Co.), Chem (v) Use of colour dyes like CI solvent 33 and solvent Abstr, 92 (1979) 8527x. green 3 as replacement for hazardous colour dyes 17 Grochowski Jerzy Woiciech & Stryszak Edwards, Pol Pat, 108, and also use of white dyes like methyl an 438 (to Wojskowa Akademia Techniczna im. Jaroslawa thraquinone40-43. The anthraquinone compounds are Dahrowskiego), Chern Abstr, 95 (1980) 45496u. 7 18 Kocsis Attila & Palmai Gyorgy, Hung Pat HU25, 926 (to reported to have low toxicity4 . Ferrokemia !pari Szoretkezet), Chem Abstr, 100 ( 1983) 9532r. (vi) Use of Red phosphorus based compositions in place 19 Karel Christiaan Hoestein, Neth Appl NL 84,00, 700, ChemAbs!l; 102 (1984) 116102p. of smoke compositions containing hexachloroet 20 Klaus Hoffmann & Paul Roth, Ger Off DE 3,41 1,533, 29, hane, zinc oxide and aluminium as red phosphorus, March 1984, Chem Abstr, 104 ( 1985) 531 04j. 16 43 is a relatively low human health hazard .3R. . 21 Helbig Wolfgang & Anders Klaus Peter, Ger Pat DD 226, 281 (to Humboldt Universitaet Berlin), Chem Abstr, 104 (1985) The various nontoxic environmentally acceptable py 53 106m. rotechnic smokes have a very bright future in the na 22 Chin Anton, Wenbters Henry A (III) & Mason Theresa D, Webstor, Proc . Eleventh Int Pyrotech Semin (1986), p 1- 11 ; tional and international civil and defence sectors. 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