Smoke, colored

1) Detonation of an explosive leading to scattering of colored material. 

These methods both of which involve vaporization and condensation of a colored material, have been found suitable only when volatile organic dyes are used as coloring materials. The choice of a suitable dye for colored smoke depends on the following  

The low vapor pressure of the dye requires a high temperature, which necessitates the use of a large quantity of fuel and oxidizer leading to inferior quality of color. Also, if the difference between the vaporization temperature and the decomposition temperature of the dye is not large, then probably decomposition increases resulting in poor quality of color. 

5 Types of Pyrotechnic Formulations 363 8KC1 + 12C02 + 12H20 + 1.06 k cal g1 

One problem which has frequently been encountered especially in the case of orange smokes, is the tendency to inflame. This problem is overcome by the addition of cooling agents and proper design of smoke emission nozzles. A typical heating mixture which is considered most efficient is potassium chlorate/ lactose, 5096/5096 and combustion takes place according to Equation 5.18. Accordingly, a typical formulation is as follows  

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These dyes are mixed to the extent of about 50% with a fuel such as lactose (20%) and an oxidizer (30%) for which K chlorate is preferred. If the mixts should still burn too hot (and thereby destroy the dye), Na or K bicarbonate are added as cooling agents. Colored smoke compns are usually used in a compressed state without a binder... 

Garcia, David J. Aikman, Loy M. McIntyre, F.L. and Shook, Thomas E. Ramd Plant Scaie Mixing Granulation and Loading of Drv Materials Purina the Manufacture of Colored Smoke Munitions Pine Bluff Arsenal, Pine Bluff,... 

Fill and Press Technology for Production of Colored Smoke Grenades Pine Bluff Arsenal. Pine Bluff, Arkansas 71602-9500 (1982). 

Titanium (Ti) is used as a major component of Ti alloys, which are used as heat-resistant Ught metals for the construction of aircraft and rockets. Though Ti is also used as an anti-acid metal, it bums in air when heated above 1500 K. TiCl4 is a Uquid used to form colored smoke in air. 

In general, the chemicals used to create color displays in the daytime are various types of dyes and oils. Though dyes and oils do not fall into the category of pyrolants that generate colored smoke by combustion reactions, they are dispersed in the atmosphere by the combustion or decomposition gases of pyrolants. Typical examples of color dyes are indigo for blue, rhodamine for red, and auramine for yel-... 

Burning Millimeters/ second Delay mixtures, colored smoke composition... 

Colored smoke compositions are a major user of potassium chlorate, and the safety record of these mixtures is excellent. 

Colored smoke compositions Gas evolution is needed to disperse the smoke particles. High temperatures are not desirable here because decomposition of the organic dye molecules will occur. Metals are not found in tiiese mixtures. Low heat fuels such as sulfur and sugars are commonly employed. 

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]. 

The ratio of oxidizer to fuel will also affect the amount of heat and gas that are produced. A stoichiometric mixture of KCIO 3 and sulfur (equation 8.1) 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. 

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. 

Potassium chlorate was used in the first successful colored-flame compositions in the mid-1800 s and it remains in wide use today in colored smoke, firecrackers, toy pistol caps, matches, and color-producing fireworks. 

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)... 

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 brilliantly-colored smoke. 

The requirements for an effective colored-smoke composition include... 

The mixture must ignite at a low temperature and continue to burn smoothly at low temperature (well below 1000°C). If the temperature is too high, the dye molecules will decompose and the color quality as well 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 [3]. 

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