An environmentally friendly red-light flare was a pyrotechnic (firework) flare which used lithium-based formulations that emitted red light. A flare is used for signaling, illumination, or defensive countermeasures in civilian or military applications. It is based on a non-hygroscopic (not absorbing air) dilithium nitrogen-rich salt that served as an oxidizer and red colorant. The U.S. Army Research Laboratory and the Ludwig Maximilian Institution were credited as the research facilities for developing this product announced in January 2018. [1]
As of 2018, this is the first documented red-light flare compound that is based on lithium and does not contain any perchlorates, halogenated materials, or strontium-based materials. [2] This formulation was assessed as having high color quality. To achieve the red-light emission from the flare, the authors report a formulation mixture of powdered magnesium and hexamine as fuels, nitrocellulose, an epoxy binder system, and lithium-based nitrogen salts as the oxidizer and color agent. When burned, users could observe a cool burning flame emitting a deep red color. [1]
Previously, many formulations for red-light-emitting pyrotechnics depended on a chemical reaction involving strontium chloride (SrCl). SrCl emits the red color after the flare is ignited. This chemical compound is known as a metastable molecular emitter, meaning, it is not stable at low temperatures but stable in excited high-temperature combustion processes. [3]
Before 2018, the formulations for red-light emitting pyrotechnic formulations included powdered metal fuels like magnesium, aluminum, strontium nitrate and perchlorate oxidizers, as well as carbon-based chlorinated organic materials such as poly(vinyl) chloride. [3]
In 2014, the EPA made a decision to develop regulations on the amount of strontium present in drinking water. [4] Strontium had been detected in 99% of all public U.S. water systems and at levels of concern in 7%. The agency reported that strontium is potentially harmful to human health. This chemical replaces calcium in the bone, interferes with bone strength, and affects skeletal development. The U.S. military training grounds were not included in the above study; therefore, the presence or percentage of strontium in their water systems were unknown. However, strontium was identified to be present in the red flares and signaling fireworks available in 2014. Due to these finding, the developers of the environmentally friendly red-light flare concluded that the development of environmentally safer flares was a necessity for users. [2]
A flare, also sometimes called a fusée, fusee, or bengala, bengalo in several European countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illumination, or defensive countermeasures in civilian and military applications. Flares may be ground pyrotechnics, projectile pyrotechnics, or parachute-suspended to provide maximum illumination time over a large area. Projectile pyrotechnics may be dropped from aircraft, fired from rocket or artillery, or deployed by flare guns or handheld percussive tubes.
Fireworks are low explosive pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays, combining a large number of devices in an outdoor setting. Such displays are the focal point of many cultural and religious celebrations, though mismanagement could lead to fireworks accidents.
Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. This trade relies upon self-contained and self-sustained exothermic chemical reactions to make heat, light, gas, smoke and/or sound. The name comes from the Greek words pyr ("fire") and tekhnikos.
Tracer ammunition, or 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 trajectory 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.
A Roman candle is a traditional type of firework that ejects one or more stars or exploding shells. Roman candles come in a variety of sizes, from 6 mm (0.24 in) diameter for consumers, up to 8 cm (3.1 in) diameter in professional fireworks displays.
A perchlorate is a chemical compound containing the perchlorate ion, ClO−4, the conjugate base of perchloric acid. As counterions, there can be metal cations, quaternary ammonium cations or other ions, for example, nitronium cation.
A sparkler is a type of hand-held firework that burns slowly while emitting bright, colored sparks. It burns in high temperature, so it can be very dangerous.
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly (deflagrates) 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.
Lithium perchlorate is the inorganic compound with the formula LiClO4. This white or colourless crystalline salt is noteworthy for its high solubility in many solvents. It exists both in anhydrous form and as a trihydrate.
A pyrotechnic colorant is a chemical compound which causes a flame to burn with a particular color. These are used to create the colors in pyrotechnic compositions like fireworks and colored fires. The color-producing species are usually created from other chemicals during the reaction. Metal salts are commonly used; elemental metals are used rarely.
Rubidium nitrate is an inorganic compound with the formula RbNO3. This alkali metal nitrate salt is white and highly soluble in water.
Colored fire is a common pyrotechnic effect used in stage productions, fireworks and by fire performers the world over. Generally, the color of a flame may be red, orange, blue, yellow, or white, and is dominated by blackbody radiation from soot and steam. When additional chemicals are added to the fuel burning, their atomic emission spectra can affect the frequencies of visible light radiation emitted - in other words, the flame appears in a different color dependent upon the chemical additives. Flame coloring is also a good way to demonstrate how fire changes when subjected to heat and how they also change the matter around them.
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.
Barium oxalate is a chemical compound with the chemical formula BaC2O4. It is a barium salt of oxalic acid. It consists of barium cations Ba2+ and oxalate anions C2O2−4. It is a white odorless powder that is sometimes used as a green pyrotechnic colorant generally in specialized pyrotechnic compositions containing magnesium metal powder. Flame color is rich and vivid without additional chlorine donors. Such compositions burn rate is satisfied without commonly used oxidizers as nitrates, chlorates and perchlorates.
Strontium carbonate (SrCO3) is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite.
A flare or decoy flare is an aerial infrared countermeasure used by an aircraft to counter an infrared homing ("heat-seeking") surface-to-air missile or air-to-air missile. Flares are commonly composed of a pyrotechnic composition based on magnesium or another hot-burning metal, with burning temperature equal to or hotter than engine exhaust. The aim is to make the infrared-guided missile seek out the heat signature from the flare rather than the aircraft's engines.
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.
Strontium oxalate is a compound with the chemical formula SrC2O4. Strontium oxalate can exist either in a hydrated form or as the acidic salt of strontium oxalate.
Alkali metal nitrates are chemical compounds consisting of an alkali metal and the nitrate ion. Only two are of major commercial value, the sodium and potassium salts. They are white, water-soluble salts with melting points ranging from 255 °C to 414 °C on a relatively narrow span of 159 °C
Signal Production Association is a company based in Chelyabinsk, Russia. It is part of NPO Pribor, a Techmash company.