User:Xanthine/Coloured Flames

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This user is a pyromaniac.

There's a lot of information out there, but it's all scattered. I'm attempting to aggregate some of it together. NB: This relates to coloured fire in firedancing and similar performances, not fireworks your mom or other pyrotechnics. As such, different considerations are necessitated.

Contents

[edit] Article Writeup

[edit] Flame Colour Emission

[edit] Fireworks and Pyrotechnics

[edit] Colouring Additives

[edit] Fire Performances

Safest Colours for performers.

  • Red - Strontium Carbonate

Hazards: None notable. Considered relatively harmless. One known case of allergy. Decomposes about 1100 C http://bulkpharm.mallinckrodt.com/_attachments/msds/S6890.htm

  • Green - Barium Sulphate

Hazards: Only dangerous after chronic exposure (inhalation). Decomposes at 1600 C http://www.jtbaker.com/msds/englishhtml/B0504.htm

  • Blue - Copper Acetate?

Hazards: May evolve potentially harmful copper (II) oxide -- respiratory tract irritant. Copper compounds may produce copper fume upon heating, potentially leading to metal fume fever. http://physchem.ox.ac.uk/MSDS/CO/copper_II_acetate.html

Copper Benzoate?

[edit] Safety Risks

[edit] Information

[edit] Wikilinks

A spectral color is a color that is evoked by the optical spectrum; every wavelength of light yields a different spectral color, in a continuous spectrum.The photons themselves have no color. Color is an effect created by the mind to make us aware of differences in photon wavelength.

Pollution Fireworks produce smoke and dust that contain heavy metals, sulfur-coal compounds and other toxic chemicals. These by-products of fireworks combustion will vary depending on the mix of ingredients of a particular firework. (Green color, for instance, is produced by adding barium, a highly noxious heavy metal.) These variables include the amount of gunpowder used, type of oxidizer, colors produced, and launch method.

  • Flame - Extract concerning colour

The color and temperature of the flame are dependent on the type of fuel involved in the combustion. For example when a lighter is held to a candle. This applied heat causes the fuel molecules to evaporate, in this state they can then react with oxygen, giving off enough heat in the exothermic reaction to sustain a consistent flame. The resulting increases in temperature tears apart some of the fuel molecules, forming various incomplete combustion products and free radicals. Sufficient energy in the flame will excite the electrons in these products, which results in the emission of visible light. As the combustion temperature increases, so does the energy of the electromagnetic radiation given off by the flame. This is why the hottest visible flame is in the blue/violet region of the visible spectrum.

There are different methods of distributing the required components of combustion to a flame. In a diffusion flame, oxygen and fuel diffuse into each other; where they meet the flame occurs. In a premixed flame, the oxygen and fuel are premixed beforehand, which results in a different type of flame. Candle flames operate through evaporation of the fuel.

Flame color depends on three components, blackbody radiation, spectral line emission, and to a lesser degree spectral line absorption. Depending on oxygen supply, which determines the rate of combustion, temperature and reaction paths, different color hues can be observed in flames. Recent discoveries by the National Aeronautics and Space Administration (NASA) of the United States also have found that gravity plays a role. [1] Pictured on the right is a Bunsen burner burning mainly methane.

In a laboratory under normal gravity conditions and with a closed oxygen valve, a Bunsen burner burns with yellow flame (also called a safety flame) at 1,000°C. With increasing oxygen supply less blackbody-radiating soot is produced, and the combustion reaction creates enough energy to ionize gas molecules in the flame, leading to a blue appearance. Flame temperatures of common items include a blowlamp at 1,300°C, a candle at 1,400°C, or a much hotter oxy-acetylene combustion at 3,000°C.

Generally speaking, the coolest part of the flame will be red, transitioning to orange, yellow and white as the temperature increases as a result of changes in blackbody radiation. For a given flame's region, the closer to white on this scale, the hotter that section of the flame is. A blue-colored flame emerges when the amount of soot decreases and the blue emissions from molecules become dominant.

  • Fire - Extract concerning science of fire

In many cases such as burning organic matter like wood or incomplete combustion of gas, incandescent solid particles, soot produces the familiar red-orange 'fire' color light. This light has a continuous spectrum. Complete combustion of gas has a dim blue color due to the emission of single wavelength radiations from various electron transitions in the excited molecules formed in the flame. Usually oxygen is involved, but hydrogen burning in chlorine produces a flame as well, producing the toxic acid hydrogen chloride (HCl). Other possible combinations producing flames, amongst many more, are fluorine and hydrogen, or hydrazine and nitrogen tetroxide. Recent discoveries by the National Aeronautics and Space Administration (NASA) of the United States also has found that gravity plays a role. Modifying the gravity causes different flame types. [6]

The glow of a flame is somewhat complex. Black-body radiation is emitted from soot, gas, and fuel particles, though the soot particles are too small to behave like perfect blackbodies. There is also photon emission by de-excited atoms and molecules in the gases. Much of the radiation is emitted in the visible and infrared bands. The color depends on temperature for the black-body radiation, and chemical makeup for the emission spectra. The dominant color in a flame changes with temperature. The photo of the forest fire is an excellent example of this variation. Near the ground, where most burning is occurring, it is white, the hottest color possible for organic material in general, or yellow. Above the yellow region, the color changes to orange, which is somewhat cooler, then red, which is cooler still. Above the red region, combustion no longer occurs, and the uncombusted carbon particles are visible as black smoke.

The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a general flame, such as in a candle in normal gravity conditions, making it yellow. In microgravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is that the cause is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs. [7] Experiments by NASA in microgravity reveal that diffusion flames in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions. [8] Premixed flames in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer. [9] These discoveries have potential applications in applied science and industry, especially concerning fuel efficiency.

[edit] An exhaustive list of flame colourant chemicals

[edit] Fuels and Solvents

  • White Gas - fuel
  • Kerosene - fuel
  • Ethanol - fuel/solvent
  • Acetone - Solvent
  • Tetrahydrofuran (THF) - Solvent
  • Methylethylketone (MEK) - Solvent

[edit] Colourants

  • Barium salts -- Colouring Agents

Used to colour fires green. several are used:

  • Barium carbonate, BaCO3 -- Colouring Agent, Stabilizer

As well as being a green flame-colourer, barium carbonate acts as a neutralizer to keep potentially dangerous acid levels down in pyrotechnic compositions.

  • Barium chlorate, Ba(ClO3)2.H2O -- Colouring Agent, Oxidiser

Used when deep green colours are needed. It is one of the more sensitive chemicals which are still used, best to avoid if possible, but if used it should be in combination with chemicals which will reduce its sensitivity.

  • Barium nitrate, Ba(NO3)2 -- Colouring Agent/Enhancer, Oxidiser

Not very strong green effect. Used with aluminium powder to produce silver effects. Below 1000C aluminium burns silvery-gold, characteristic of aluminium-gunpowder compositions. Above 1000C it burns silver, and may be achieved using barium nitrate. Boric acid should always be used in compositions containing barium nitrate and aluminium.

  • Barium oxalate, BaC2O4 -- Colouring Agent

Sometimes used, generally in specialised items with magnesium.

  • Copper and copper compounds -- Colouring Agents

Used to add both green and blue colours to flames:

  • Copper metal, Cu -- Colouring Agent

Both the bronze and electrolytic forms are occasionally used, but easier methods are available for the same effect.

  • Copper acetoarsenate, C4H6As6Cu4O16 -- Colouring Agent

Commonly called Paris Green, this chemical is toxic but used to produce some of the best blue colours in combination with potassium perchlorate.

  • Copper carbonate, CuCO3 -- Colouring Agent

This is the best copper compound for use with ammonium perchlorate for production of blue colours. Also used in other blue compositions.

  • Copper (I) chloride, CuCl -- Colouring Agent

Cuprous chloride is probably the best copper compound for creating blue and turquoise flames, and it can be used with a variety of oxidizers. It is non-hygroscopic and insoluble in water, but it is oxidised slowly in air.

  • Copper oxides, CuO/Cu2O -- Colouring Agent

Used for many years for blues, but needed mercury chloride to intensify colours. Seldom used.

  • Copper oxychloride -- Colouring Agent

Occasionally used in cheap blue compositions.

  • Lithium carbonate, Li2CO3 -- Colouring Agent

Used to colour fires red. It has no advantage over strontium salts for the same purpose.

  • Sodium salts -- Colouring Agents

Sodium salts are sometimes used in place of the corresponding potassium salts, but this is uncommon due to their hygroscopic nature. They rapidly absorb water from the air, which can ruin a pyrotechnic composition. In particularly dry environments they can be used without too much trouble, and are therefore used in places like Egypt due to the relative cheapness of some of the salts with respect to the potassium ones. Sodium salts are also used as colourising agents, producing a characteristic orange flame.

  • Strontium salts -- Colouring Agents

Used to colour flames a brilliant red:

  • Strontium carbonate, SrCO3 -- Colouring Agent, Retardant

Used often for producing red colours, and as a fire retardant in gunpowder mixtures.

  • Strontium oxalate, SrC2O4 -- Colouring Agent, Retardant, Stabilizer

As for strontium carbonate, generally, but suffers from greater water content.

  • Strontium nitrate, Sr(NO3)2 -- Colouring Agent, Oxidiser

This is the most commonly used strontium salt, because it provides the most superb red colour available. Best results will be acheived if the strontium nitrate is anhydrous.

[edit] Colour Enhancers

  • Calcium oxalate, CaC2O4 -- Colour Enhancer

Used to add depth to colours produced by other metal salts.

  • Hexachlorobenzene (HCB), C6Cl6 -- Colour Enhancer

Used as a chlorine donor in coloured compositions that require one. Rarely used, with PVC, Saran and Parlon being preferred.

  • Parlon -- Colour Enhancer, Binder

Parlon is a chlorine donor, and a key ingredient in many coloured stars. It is a chlorinated isoprene rubber, chlorine content 66%. It interferes with burning less than PVC or saran, and can be used as a binder. It is soluble in methyl ethyl ketone (MEK) and partially in acetone. Compositions made with parlon and acetone or MEK are nearly waterproof.

  • Polyvinylchloride (PVC) -- Colour Enhancer, Binder

PVC is a commonly used chlorine donor. It is not as good as Parlon for this purpose, but is cheaper and more readily available. PVC is soluble in tetrahydrofuran (THF) but almost all other solvents are useless. Methyl ethyl ketone (MEK) will plasticise PVC to some extent, however.

  • Saran -- Colour Enhancer, Binder

Saran is another plastic chlorine donor. It is most commonly encountered in the form of the cling wrap used to protect foodstuffs. It is slightly soluble in tetrahydrofuran (THF) and will be plasticised by methyl ethyl ketone (MEK).


[edit] DMP Research

[edit] Coloured Fire/Star Mixes

The following compositions can be burned loose, in a small pile to produce a colored flame. They can also be made into "Stars". Stars are solid chunks of pyrotechnic compositions that are designed to either burn in various bright colors, or produce an effect such as glitter, streamer/tail, etc. while traveling through the air. Stars are the basis of Aerial Shells that paint the sky during firework displays. To make any of the following compositions into Stars, simply add a little water to them until the mixture has the consistency of cookie dough. Once in this form, the composition can be pressed or rolled into small pellets and dried. Once the pellets have thoroughly dried and become hard, they are known as 'Stars'. Never force dry pyrotechnic compositions with heat. Always dry them in the open air and in the shade. Depending on the type of composition and temperature/humidity, drying times for a batch of stars can take from about 3 to 7 days.


Double Neon Blue

  • Potassium Perchlorate 127.6 g
  • Copper Carbonate 25.8 g
  • Parlon 27.6 g
  • Dextrin 8.6 g
  • Red Gum 19.0 g

Purple

  • Potassium Perchlorate 122.6 g
  • Copper Carbonate 14.8 g
  • Strontium Carbonate 10.0 g
  • Parlon 24.8 g
  • Dextrin 18.2 g
  • Red Gum 19.0 g

Pink

  • Potassium Perchlorate 140.0 g
  • Strontium Carbonate 30.0 g
  • Dextrin 8.0 g
  • Charcoal 4.0 g
  • Red Gum 18.0 g

Lemon Lime Green

  • Potassium Perchlorate 94.4 g
  • Barium Nitrate 56.6 g
  • Strontium Carbonate 10.0 g
  • Parlon 9.4 g
  • Dextrin 10.0 g
  • Red Gum 28.4 g

White

  • Potassium Nitrate 140.0 g
  • Antimony Sulfide 30.0 g
  • Sulfur 14.0 g
  • Dextrin 7.5 g

Electric Orange

  • Potassium Perchlorate 106.0 g
  • Calcium Carbonate 28.0 g
  • Magnalium 12.0 g
  • Parlon 28.0 g
  • Dextrin 8.0 g
  • Red Gum 18.0 g

This is the most intense pumpkin orange you'll ever see. 'Electric' colors are much brighter and vibrant than normal mixtures. This is due to the presence of a metal in the mixture (usually Magnalium or Aluminum). The burning metal dramatically increases the flame temperature and also the visible luminous output.

Electric Magenta

  • Potassium Perchlorate 16.0 g
  • Strontium Nitrate 76.0 g
  • Charcoal 10.0 g
  • Sulfur 10.0 g
  • Magnalium 24.0 g
  • Copper Carbonate 20.0 g
  • Parlon 36.0 g
  • Dextrin 8.0 g

This is a breathtaking color, producing an absolutely intense magenta color. 'Electric' colors are much brighter and vibrant than normal mixtures. This is due to the presence of a metal in the mixture (usually Magnalium or Aluminum). The burning metal dramatically increases the flame temperature and also the visible luminous output.

Electric Red

  • Potassium Perchlorate 106.0 g
  • Strontium Carbonate 28.0 g
  • Magnalium 12.0 g
  • Parlon 28.0 g
  • Dextrin 8.0 g
  • Red Gum 18.0 g

Electric Yellow

  • Potassium Perchlorate 90.0 g
  • Cryolite 26.0 g
  • Magnalium 60.0 g
  • PVC 10.0 g
  • Charcoal 4.0 g
  • Dextrin 10.0 g

Electric Green

  • Potassium Perchlorate 58.0 g
  • Barium Nitrate 46.0 g
  • Barium Carbonate 28.0 g
  • Magnalium 22.0 g
  • Parlon 28.0 g
  • Red Gum 10.0 g
  • Dextrin 8.0 g

[edit] Wiki Categories

  • Category:Color
  • Category:Fire
  • Category:Circus_skills
  • Category:Juggling
  • Category:Pyrotechnics

[edit] Weblinks/Collected Information


[edit] Coloured fire in religion and mythology

[edit] Supporting Information

[edit] Footnotes

Interestingly, earth, water, air, and fire - the original four elements - actually describe the four states of matter; solid, liquid, gas, and plasma respectively.