Cleaner, greener fireworks

Boron carbide could way to less toxic green pyrotechnics light.Shows, like this soon greener could at the same time just as green.NICK FIELDING / Alamy

Call a Flash inspiration. A US Army team of pyrotechnics experts detected that connect long as inert released the toxic metal currently used in green colored fireworks could replace.

Chemist Jesse Sabatini and his colleagues at Picatinny Arsenal in New Jersey found that boron carbide used the green-light-emitting performance of barium-based connections in today's Fireworks.

Replace the barium with boron cut the amount of the toxic material of fireworks released. This is particularly important in places where displays for every day, as theme parks, instead of which can get the links. However, it is personal, look, benefit most from the discovery of the army. Flares are pyrotechnics greatly by the military in signal on the battlefield, as well as on the training ground to simulate the explosions and shots of the fight.

"In the military world, where you use large amounts of pyrotechnics on a daily basis, it is [barium exposure] a real problem," says Thomas Klap?tke, the clean pyrotechnics to explore the University of Munich in Germany and was not in the new study.

Sabatini was by the U.S. Army signal flare come with with a barium free, low-cost alternative to the green-light-emitting hand held M125A1 charged. These flares are based on a combination of barium nitrate and polyvinyl chloride (PVC) which emit burning to form barium chloride and green light. Apart from the toxicity of the barium has its own environmental issues burn PVC, because it released toxic polychlorinated biphenyls.

For a replacement of barium and chlorine-free, the team saw boron. As the powdery form eliminates the element it is boron oxide and free green light. Unfortunately, it burns so quickly that green light is lost too quickly to useful be.

The team found that they could expand the burn time with the addition of crystalline boron into the mix. But crystalline boron is expensive.

"It seemed that we were on the verge of a breakthrough, so we decided to"exotic"boron compounds, looking up," said Sabatini. "We saw some really classic chemistry papers from behind in the 1950s and 1960s, who said that although boron carbide very apathetic it is indeed reactive at room temperature, at high temperatures."

Add more boron carbide, amorphous boron successfully expanded the burning time, reported the team in applied Chemie1. Finally she decided to try it pure and were "very surprised" if it ignited, said Sabatini. Pure boron carbide was the best burning time of all have.

Klap?tke is surprised by the performance of boron Carbide. "It is thermally very stable - chemist would say it is dead, it will not do anything." And I think, no one ever tried using it in this way, "says he."

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Boron carbide is how add a viable replacement for Barium nitrate, Klap?tke, because the pyrotechnic fields with it long burn times, reasonable spectral purity and high light intensity is ticking. It is used in the real world as an industrial abrasive so there are fewer obstacles with regard to toxicity and environmental data, adoption. Perhaps most importantly is ammonium carbonate, nitrate - and availability has cheaper than barium a cheap price - ready.

For the commercial fireworks industry as well as the military of be sure costs to the adoption of new pyrotechnic formulations, Martin van Tiel, the van Tiel says pyrotechnics Fireworks headquartered in Waikato in New Zealand operates.

"For something new, cost and performance are the key - if it twice as much will be no one interested in costs," says van Tiel. "In the history of Fireworks has develop it - people are very happy to give it a try." "The fireworks industry can be quite fast."

Sabatini, j. j., Poret, j.-C. &Amp; wide, R. N. Angew. Chem. Int. EDN. online publication doi:10.1002/anie.201007827 (6 April 2011) to advance.If you something offensive or inappropriate or that otherwise are not met our conditions or Community guidelines, select you the appropriate "this comment report" Link.Kommentare on this thread are marked according to the time of booking.

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