Smoke composition

Last updated

A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades.

Contents

Obscurants

Smoke compositions used as obscurants generate large amount of thick, usually white, smoke. The most common smoke composition for pyrotechnic generation of smoke screens is the zinc chloride smoke mixture (HC).

Zinc chloride smoke

Zinc chloride smoke is grey-white and consists of tiny particles of zinc chloride. The most common mixture for generating these is the zinc chloride smoke mixture (HC), consisting of hexachloroethane, grained aluminium and zinc oxide. The smoke consists of zinc chloride, zinc oxychlorides, and hydrochloric acid, which absorb the moisture in the air. The smoke also contains traces of organic chlorinated compounds, phosgene, carbon monoxide, and chlorine.

Its toxicity is caused mainly by the content of strongly acidic hydrochloric acid, but also due to thermal effects of reaction of zinc chloride with water. These effects cause lesions of the mucous membranes of the upper airways. Damage of the lower airways can manifest itself later as well, due to fine particles of zinc chloride and traces of phosgene. In high concentrations the smoke can be very dangerous when inhaled. Symptoms include dyspnea, retrosternal pain, hoarseness, stridor, lachrymation, cough, expectoration, and in some cases haemoptysis. Delayed pulmonary edema, cyanosis or bronchopneumonia may develop. The smoke and the spent canisters contain suspected carcinogens.

The prognosis for the casualties depends on the degree of the pulmonary damage. All exposed individuals should be kept under observation for 8 hours. Most affected individuals recover within several days, with some symptoms persisting for up to 1-2 weeks. Severe cases can suffer of reduced pulmonary function for some months, the worst cases developing marked dyspnea and cyanosis leading to death.

Respirators are required for people coming into contact with the zinc chloride smoke.

White phosphorus

White phosphorus is a popular base for smoke production. It is used in artillery shells, bombs, and grenades.

Signalling

A colored smoke composition can be used for signalling. These are usually based on a low-temperature burning pyrotechnic composition, mixed with a dye that gets vaporized and creates large, colored smoke particles. The composition is often based on an oxidizer (e.g. potassium chlorate, potassium nitrate, or potassium perchlorate), a fuel (e.g. lactose), an optional coolant (e.g. sodium bicarbonate), and one or more dyes.

Fire extinguishing

Smoke with a suitable composition can be used as a fire suppression agent. A pyrotechnic composition similar to black powder, composed of 15% charcoal and 85% potassium nitrate, generates thick smoke composed of particles of mainly potassium carbonate, which has fire extinguishing properties. Two-kilograms smoke grenades, thrown into burning rooms through plate-glass windows, have been used by some European firefighters. [1]

Dispersion of chemicals

Smoke compositions can be used also for creating aerosol of other materials than dyes. Generally the same type of pyrotechnic composition as for colored smokes is used, with the dye being replaced by the desired chemical. The devices usually have the form of smoke bombs.

The best known such application of smoke compositions is in riot control, for dispersion of lachrymatory agents. The agent used is most often CS gas, with less used alternatives CR gas, CN gas and Adamsite.

In agriculture, smoke compositions are used to disperse insecticides and fungicides. Some agents used in this manner are permethrin, cypermethrin, chlorpyrifos, imazalil, etc., and some fumigation agents.

Smoke compositions can be also used for weather modification, namely cloud seeding, to provide cloud condensation nuclei for the moisture to precipitate.

Related Research Articles

<span class="mw-page-title-main">Potassium chloride</span> Ionic compound (KCl)

Potassium chloride is a metal halide salt composed of potassium and chlorine. It is odorless and has a white or colorless vitreous crystal appearance. The solid dissolves readily in water, and its solutions have a salt-like taste. Potassium chloride can be obtained from ancient dried lake deposits. KCl is used as a fertilizer, in medicine, in scientific applications, domestic water softeners, and in food processing, where it may be known as E number additive E508.

The compound hydrogen chloride has the chemical formula HCl and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl.

<span class="mw-page-title-main">Potassium chlorate</span> Chemical compound

Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It is a strong oxidizing agent and its most important application is in safety matches. In other applications it is mostly obsolete and has been replaced by safer alternatives in recent decades. It has been used

<span class="mw-page-title-main">Tracer ammunition</span> Illuminated pyrotechnic ammunition visible in daylight and darkness

Tracer ammunition (AMO) (Tracers) are bullets or cannon-caliber projectiles that are built with a small pyrotechnic charge in their base. When fired, the pyrotechnic composition is ignited by the burning powder and burns very brightly, making the projectile trajectory visible to the naked eye during daylight, and very bright during nighttime firing. This allows the shooter to visually trace the flight path of the projectile and thus make necessary ballistic corrections, without having to confirm projectile impacts and without even using the sights of the weapon. Tracer fire can also be used as a marking tool to signal other shooters to concentrate their fire on a particular target during battle.

<span class="mw-page-title-main">Flux (metallurgy)</span> Chemical used in metallurgy for cleaning or purifying molten metal

In metallurgy, a flux is a chemical cleaning agent, flowing agent, or purifying agent. Fluxes may have more than one function at a time. They are used in both extractive metallurgy and metal joining.

<span class="mw-page-title-main">Smoke bomb</span> Type of firework

A smoke bomb is a firework designed to produce a large amount of smoke upon ignition.

<span class="mw-page-title-main">Smoke screen</span> Airborne obscurant using gas and particulates

A smoke screen is smoke released to mask the movement or location of military units such as infantry, tanks, aircraft, or ships.

<span class="mw-page-title-main">Flash powder</span>

Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and produces a loud noise regardless of confinement. It is widely used in theatrical pyrotechnics and fireworks and was once used for flashes in photography.

<span class="mw-page-title-main">Acetyl chloride</span> Organic compound (CH₃COCl)

Acetyl chloride is an acyl chloride derived from acetic acid. It belongs to the class of organic compounds called acid halides. It is a colorless, corrosive, volatile liquid. Its formula is commonly abbreviated to AcCl.

Phosgene oxime, or CX, is an organic compound with the formula Cl2CNOH. It is a potent chemical weapon, specifically a nettle agent. The compound itself is a colorless solid, but impure samples are often yellowish liquids. It has a strong, disagreeable and irritating odor. It is used as a reagent in organic chemistry.

<span class="mw-page-title-main">Colored smoke</span> Type of smoke

Colored smoke is a kind of smoke created by an aerosol of small particles of a suitable pigment or dye.

A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic substances do not rely on oxygen from external sources to sustain the reaction.

<span class="mw-page-title-main">Hexachloroethane</span> Chemical compound

Hexachloroethane, also known as perchloroethane is the organochlorine compound with the chemical formula (CCl3)2. It is white solid at room temperature with a camphor-like odor. It has been used by the military in smoke compositions, such as base-eject smoke munitions.

<span class="mw-page-title-main">AN-M8 smoke grenade</span>

The AN-M8 HC Smoke Grenade designated as the Army/Navy Model 8 HC Smoke Grenade is a US military grenade used as a ground-to-ground obscuring or screening device or a ground-to-air signaling or target-marking device.

Ammonium perchlorate composite propellant (APCP) is a solid-propellant rocket fuel. It differs from many traditional solid rocket propellants such as black powder or zinc-sulfur, not only in chemical composition and overall performance but also by the nature of how it is processed. APCP is cast into shape, as opposed to powder pressing as with black powder. This provides manufacturing regularity and repeatability, which are necessary requirements for use in the aerospace industry.

In pyrotechnics, a pyrotechnic initiator is a device containing a pyrotechnic composition used primarily to ignite other, more difficult-to-ignite materials, such as thermites, gas generators, and solid-fuel rockets. The name is often used also for the compositions themselves.

Delay composition, also called delay charge or delay train, is a pyrotechnic composition, a sort of pyrotechnic initiator, a mixture of oxidizer and fuel that burns in a slow, constant rate that should not be significantly dependent on temperature and pressure. Delay compositions are used to introduce a delay into the firing train, e.g. to properly sequence firing of fireworks, to delay firing of ejection charges in e.g. model rockets, or to introduce a few seconds of time between triggering a hand grenade and its explosion. Typical delay times range between several milliseconds and several seconds.

Wet Processing Engineering is one of the major streams in Textile Engineering or Textile manufacturing which refers to the engineering of textile chemical processes and associated applied science. The other three streams in textile engineering are yarn engineering, fabric engineering, and apparel engineering. The processes of this stream are involved or carried out in an aqueous stage. Hence, it is called a wet process which usually covers pre-treatment, dyeing, printing, and finishing.

<span class="mw-page-title-main">Silver diethyldithiocarbamate</span> Chemical compound

Silver diethyldithiocarbamate is a chemical compound. It is the silver salt of diethylthiocarbamic acid.

References

  1. Russell, Michael S. (2009). The Chemistry of Fireworks. ISBN   9780854041275.