Fireworks are made of barrel shells (paper, plastic, thin metal sheets, etc.), pyrotechnic agents, sealing substances, accessories (such as tail wing bases, cross arms, shafts, rods), ignition devices (such as leads, wipers, etc.) Fire board, electric ignition head, etc.). It makes use of the effects of light, color, sound, aerodynamics, and smoke generated when the pyrotechnic agent burns or explodes, making fireworks
a kind of ornamental product.
Why do fireworks have colorful colors
Fireworks are made by adding magnesium, aluminum, antimony and other metal powders in gunpowder (the main components are sulfur, carbon powder, potassium nitrate, etc.) in a certain proportion It is made of metal compounds such as strontium, barium, and sodium. Because different metals and metal ions burn in different colors (a ‘flame color reaction’), fireworks burst into colorful sparks when they explode in the air. For example, aluminum-magnesium alloys burn brilliantly white; strontium nitrate and lithium burn red; sodium nitrate burns yellow; and barium nitrate burns green.
In addition to metals and metal compounds, various doses of oxidizing agents, light aids and binders are added to fireworks. The oxidant will generate a lot of oxygen when burning, which plays a role in supporting combustion and making the color of the fireworks more vivid; the light booster can greatly improve the brightness of the fireworks; the binder is used to form the powdery compound into light agent particles of different sizes. If these particles are arranged according to certain rules, fireworks of different patterns can be made. For example, the ‘sunflower’ is surrounded by yellow-emitting particles in a circle, and green particles are placed around it. When the sky explodes, a sunflower with green leaves will be formed, which is extremely beautiful.
The color of fireworks is caused by the different colors of the flame reaction caused by the burning of different metals. Fireworks use various metal powders to burn in high heat to form various dazzling colors. Using different metals can produce different effects and emit different colors of light.
Flame Reaction:
Sodium (Na): Yellow
Lithium (Li): Purple
Potassium (K): Light Purple
Rubidium (Rb): Purple
Cesium (Cs): Purple
Calcium (Ca): Brick Red
p>
Strontium (Sr): Magenta
Copper (Cu): Green
Barium (Ba): Yellow-green
Fireworks Main ingredient
The main ingredient of firecrackers and fireworks is nitrocellulose, which has been added with stabilizer, which is 3 times more efficient than traditional black powder. Efficient and smoke-free.
The main ingredient of firecrackers is black powder, which contains sulfur, charcoal powder, potassium nitrate, and some potassium chlorate. Magnesium powder, iron powder, aluminum powder, antimony powder and inorganic salt are also added when making flash thunder, electro-optical cannon, fireworks cannon and colored fireworks. When the fireworks are ignited, charcoal powder, sulfur powder, metal powder, etc. will burn rapidly under the action of oxidants, producing carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen monoxide, nitrogen dioxide and other gases and dust of metal oxides, and at the same time, a large amount of dust is produced. Light and heat cause firecrackers to explode. Paper scraps, soot and harmful gases are flying around along with the sound and firelight, making the smoke filled at the discharge site, and the sulfur oxides, nitrogen oxides, carbon oxides and other serious pollution of the air. These gases are irritating to the human respiratory tract and eyes.
The main raw material of pyrotechnics in fireworks
(1) Potassium nitrate: Potassium nitrate is a strong oxidant. It is not advisable to mix potassium nitrate with ammonium perchlorate in the preparation of pyrotechnic composition. Because potassium nitrate will react with ammonium perchlorate to produce highly hygroscopic ammonium nitrate, if these chemicals contain light metal powders, these metal powders may get wet and heat up, and even spontaneously ignite and explode.
(2) Potassium chlorate: Potassium chlorate is particularly sensitive. After it is mixed with organic matter, sulfur, sulfide, acid or other easily oxidizable substances, it can produce strong combustion when heated or subjected to impact and friction. and explosion. Potassium chlorate is easily decomposed by sunlight, producing extremely unstable potassium chlorite and potassium oxide with strong hygroscopicity. Potassium chlorite is extremely unstable.
(3) Barium nitrate: barium nitrate has good chemical stability and low mechanical sensitivity at room temperature, but when mixed with potassium chlorate, it is easy to generate highly sensitive barium chlorate, which can be combined into pyrotechnic powder It may cause spontaneous combustion and self-explosion.
(4) Potassium perchlorate: The chemical stability of potassium perchlorate is better than that of potassium chlorate. It will explode when mixed with sulfide cyanate, and has strong explosive performance when mixed with organic matter.
(5) Sulfur: The mixture of sulfur and potassium chlorate can form an explosive substance with high sensitivity, and it will explode when it is hit or rubbed. Sulfur is a poor conductor of heat and electricity. Static electricity will be generated, causing spontaneous combustion and explosion. Sulphur dust will form an explosive mixture with oxygen in the human air. When the sulfur content exceeds 7 mg per liter of air, it will explode when it encounters a fire source.
(6) Aluminum powder: Aluminum powder is easily soluble in dilute acid. It will chemically react with water when exposed to water or damp, resulting in high temperature. If it is not diffused in time, it will cause spontaneous combustion and self-explosion. When there is more than 40 mg of aluminum powder per liter of air, it will explode when it encounters a fire source.
(7) Magnesium powder: Magnesium powder, like aluminum powder, will spontaneously ignite and explode when exposed to moisture. When there is 10-25 mg of magnesium powder per liter of air, it will explode when encountering a fire source.
(8) Magnesium-aluminum alloy powder: generally composed of about 50 percent of magnesium and aluminum, intermetallic, and its chemical stability is better than that of magnesium powder or aluminum powder alone. When the air contains 32.5 mg of alloy powder per liter, it will explode when exposed to a fire source. After being affected by moisture and water, oxides will be formed, hydrogen will be released, and a lot of heat will be generated. If the heat is not dissipated in time, it will spontaneously ignite or explode.
(9) Antimony sulfide: Antimony sulfide is used as reducing agent and combustion accelerant in pyrotechnic powder. Stable, but since it inevitably carries some silica (sand), it greatly increases the mechanical sensitivity of the pyrotechnic charge. In addition, there is antimony pentasulfide, which is a strong reducing agent and has a higher sensitivity than disulfide trisulfide.
(10) Red phosphorus (also known as red phosphorus): Red phosphorus is a strong reducing agent, which is easily oxidized in the air and produces spontaneous combustion. The mixture of red phosphorus and potassium chlorate is In 20 percent of cases, it will spontaneously ignite and explode after a little impact or friction. When red phosphorus burns, it produces toxic white fumes of phosphorus pentoxide. The red phosphorus used as a pyrotechnic agent is not allowed to have traces of yellow phosphorus (white phosphorus), because the ignition point of yellow phosphorus is very low (only 30 degrees Celsius), and it is easy to spontaneously ignite when mixed with other drugs to make products.
(11) Nitrocellulose: Nitrocellulose is highly flammable and explosive, and its danger depends on the degree of nitrification. Nitrocellulose with a nitrogen content of more than 12.5 percent is extremely dangerous and will burn upon fire. . When the temperature exceeds 40 ??, it can accelerate its decomposition and spontaneously ignite. Nitrocellulose with a nitrogen content of less than 12.5 percent is relatively stable, but when heated or stored for a long time, it gradually decomposes and releases acid, which reduces the ignition point and may also spontaneously ignite and explode. In case of fire, it is strictly forbidden to cover with sand and other materials to avoid explosion.