Aluminum Atomized Spherical is increasingly used in fireworks although there are only limited uses for it. This is because spherical or spindle-shaped particles are more difficult to ignite than a flake. It is needed for glitter effects and other special stars.
The finest powders (e.g., German Dark and XD-30) can be ‘airfloat’ and are commonly used in flash compositions. Fine aluminum atomized spherical is also used in small percentages in some hobby-rocket fuels. Courser powders are generally used for sparkling effects. With these larger particle types, many effects–such as flitter, glitter, firefly and snowball–can be achieved.
Atomized Aluminum powder (aluminum granules) results from melting and thereafter spray-drying (freezing) aluminum into small individual particles using compressed gas to draw the metal through a nozzle. Manufacturing of atomized aluminum powder can vary but the general shape, metal chemistry (alloy), and particle size distribution are the main product characteristics that define atomized aluminum products. Through the variance of these three general factors, one can determine the best atomized aluminum product for his or her application
Aluminum is a neurotoxin that alters the function of the blood-brain barrier. Additionally, small particles that are airborne act as tiny razors when they come in contact with lung or eye tissue. A dust mask and goggles should be worn at all times when working with aluminum powder. Mixtures containing nitrates and aluminum powder are prone to heating up spontaneously and may ignite, especially when wet. This is caused by the reduction of the nitrate by aluminum, forming amides. These very basic compounds react further with aluminum atomized spherical powder in a very exothermic reaction that can cause spontaneous ignition. An ammonia smell is often produced in this reaction. Adding 1 to 2% boric acid to compositions containing nitrates and aluminum is common practice and will often prevent spontaneous ignition.