Common materials used in fireworks: 13. Properties of aluminium powder.

XIII.Properties of aluminium powder English name aluminium powder; molecular formula A1, molecular weight 26.97.

1. Physico-chemical properties. Appearance and properties: silvery white powder; melting point: 660°C; boiling point: 2056°C; relative density (water = 1): 2.70; saturated vapour pressure: 0.13 kPa (1284°C); heat of combustion: 822.9 kJ-mol; minimum ignition energy: 15 MJ; maximum explosion pressure: 0.415 MPa; solubility: insoluble in water. Soluble in alkalis, hydrochloric acid and sulphuric acid.
2. Health hazards Prolonged inhalation may cause aluminium pneumoconiosis. Symptoms include emaciation, fatigue, breathing difficulties, cough and phlegm. If in the eyes, may cause focal ring death, corneal pigmentation, lens membrane changes and vitreous opacity. May irritate the mucous membranes of the nose, mouth and genitalia, causing ulcers. May cause acne, eczema and dermatitis.
3. Hazardous properties. This product is flammable and can be irritating when wet. Large amounts of dust may ignite spontaneously if exposed to moisture or water vapour. Mixture with oxidising agents may form explosive mixtures; contact with fluorine, chlorine, etc. may cause violent chemical reactions; contact with acids and strong bases may produce hydrogen, which may cause combustion and explosion. Powder and air can form explosive mixtures, which can explode when a certain concentration is reached.
4. Emergency measures in the event of a spill Isolate the leaking contaminated area and restrict entry. Cut off the source of the fire. Emergency personnel should wear self-contained positive pressure respirators and anti-static work clothing. Avoid direct contact with spilled material. Small spills: avoid dust formation, collect with a clean shovel in a dry, clean lidded container and transfer for recycling. Large spills: Cover with plastic sheeting, canvas, etc. and transfer using non-sparking tools for recycling.
5. Extinguishing methods Strictly forbid the use of water, foam, carbon dioxide, etc. for extinguishing the fire; dry sand, stone dust, etc. are appropriate.