Potassium denoted by the symbol ‘K‘ is a chemical element found in various minerals like sylvite, langbeinite, kainite, and carnallite. It is not present in its elemental form because it is highly reactive in nature. The atomic number of this element is 19. Many students wonder about its use in fireworks. So, in this article, I will answer you in detail why potassium is used in fireworks?
So, why is potassium used in fireworks? Potassium is used in fireworks because it helps in oxidizing the mixture of fireworks. Fireworks contain compounds like potassium perchlorate, potassium chlorate that are good oxidizers. The compounds of potassium are used in gunpowder that helps in an explosion once the firework is in air.
Potassium contributes 2.1% of the total weight of the earth’s crust. It comes at the eighth position in the abundance of elements in the earth’s crust. As potassium is highly reactive in air, It is not a good idea to put potassium powder in open space. Because it is flammable and also an explosion hazard.
Potassium is not present free in nature. It is present in various minerals like carnallite, langbeinite, kainite, and sylvite. The minerals that contain the content of potassium are also termed as potash.
In the periodic table, potassium is placed in the first column. Its atomic weight is 39.0983 u. The unit of measurement of the mass of an atom is atomic mass is AMU (atomic weight unit). 1 AMU is 1.66 x 10-24 grams.
Potassium is classified as an alkali metal that was discovered by Sir Humphry Davy in the year 1807. At room temperature, it exists in the solid-state. The density of potassium at room temperature is 0.86 grams per cm cubed. The melting point of potassium is around 63.38°C (146.08°F). Its boiling point comes out to be around 759°C (1398°F).
How is potassium used in fireworks?
Potassium compounds (potassium nitrate, potassium perchlorate, potassium chlorate, and many others) are good oxidizing agents. These compounds on the exposure of air react fastly. Pure potassium is never used in firecrackers but, the compounds of potassium are used in them.
If we talk about potassium nitrate (KNO3), it exists in the form of black powder. And you may have noticed that many firecrackers contain black powder similar to potassium nitrate.
Potassium nitrate is a mostly used oxidizer in large varieties of fireworks. These are used in spark effect stars firecrackers. Aluminum powder is also an important mixture of flash powder used in fireworks.
The balanced reaction of the fireworks containing a mixture of potassium nitrate (black powder) and aluminum powder.
2 KNO3 + 4 Al + S ——–air——> K2S + N2 + 2Al2O3
The ratio of the content of flash powder used is 59% part of potassium nitrate, to 31.6% of aluminum powder, to 9.4% of sulfur.
Potassium chlorate is also widely used powder in fireworks. This powder came into use in a mixture of fireworks as good colored flames were possible with this powder. This helps in quality color composition. A few examples of firecrackers using this mixture are pull-string crackers, toy cap guns.
The stoichiometrically balanced reaction for this powder is:
KClO3 + 2Al ——-air—–> Al2O3 + KCl
The ratio of composition is around 70% of Potassium Chlorate to 30% of aluminum powder by weight.
It came into use in the mixture of flash powder as a replacement of potassium chlorate. The mixture containing potassium perchlorate is safer and due to which, they are largely used in the fireworks as an oxidizer. This powder has lesser sensitivity to ignition through friction or by an accidental impact. The reaction of firework containing a mixture of this compound with aluminum powder is shown below.
3 KClO4 + 8 Al —–air—–> 3 KCl + 4 Al2O3
The stoichiometric ratio of content in this powder used in flash works is 34.2% of aluminum to 65.8% of perchlorate of their weights.
These salts are also commonly used in the manufacturing of fireworks due to the following reason:
- They do not absorb moisture from the air so easily.
- Potassium spectra do not produce interference in color composition with the spectra of the desired color.
- Potassium salts are easily available as they are inexpensive.
List of elements used in fireworks
Carbon: It acts as a fuel to the powder of firework. It is used as a propellent.
Aluminum: the aluminum powder helps in producing white and silver sparks and flames.
Potassium: potassium is an oxidizer in a mixture of firework. The compound of potassium like potassium perchlorate, potassium nitrate, and potassium chlorate are all oxidizers.
Sodium: sodium imparts yellow or gold flames on burning.
Phosphorus: It has a property to burn spontaneously and also known for its glow-in-dark effect.
Zinc: It is used in flash powder for producing smoke effects on a burning firework.
Magnesium: It produces white sparks on burning. As it burns with a bright white flame so, it is used in flash powder.
Calcium: it deepens the color of firework. Calcium produces orange sparks on burning in the form of the flash powder mixture.
Copper: Copper compounds in the mixture of firework powder produce blue colors of sparks in fireworks.
Lithium: It is responsible for imparting a red color flame on the burning of fireworks.
Fireworks ignition temperature
The fireworks should be handled properly because they are dangerous if not burned in a proper way,
It should be noted that when fireworks burn, their temperature can reach up to 1000 °C (1,800 °F). This is a high temperature that can very easily burn your skin and also can cause a life threat in case of major fire cause in firework industries.
The color of fireworks are formed in two ways:
Luminescence: This is the phenomenon of emission of light by a substance that is relatively cool. The light is produced when the substance absorbs the energy from an external source and then re-emits the energy in the form of the colorful and visible light.
Incandescence: this is the phenomenon in which the light is produced on heating the substance to such extent that it starts glowing. On this glow, the color of light is produced that is known as incandescence light.
The heat causes the substance to become hot and with this heat emission, the color of substance starts glowing. At the initial point, the substance emits infrared. After that, the color changes red, orange, yellow and then white.
With the variation in temperature, the color can be changed.
Is Magnesium used in fireworks?
Yes, magnesium is also used in the manufacturing of fireworks. It produces white flames of light on burning firecrackers. So, it is used to impart white color to the flames and sparks.
With its white flame light, the overall impression of burning fireworks improves.
Safety measures while burning fireworks
Always burn firecrackers in open space and make sure people are out of range of that area.
Burn one firecracker at one time
Always read the instructions on the cover of fireworks before burning them
Do not allow kids to burn strong firecrackers.
Always keep the water sources nearby, in case of fire or mishappening.
Always wear goggles while burning crackers, because sometimes their spark can directly fly on your face.
Avoid carrying fireworks in your pocket.
Always but fireworks from the reliable retailer as expired fireworks can lead to an accident.