The Atomisation Process

Atomisation is the breaking up of liquid into droplets (Fig 1). If a molten material is atomised into droplets, these normally cool rapidly to produce solid particles. Thus one could say that granulation and atomisation are conceptually identical, differing only in the size of particles produced. Granulation produces granules, which may loosely be defined as particles of the millimetre range (sometimes up to >10mm). Atomisation is normally taken, in a metallurgical context, to imply that the particles resulting are ìpowderî which can loosely be taken to mean substantially sub-millimetre range particles. In fact atomised metal powders are produced with sizes ranging from a few microns to a millimetre. Given that this spans nearly 3 orders of magnitude, the processes used to make and handle particles of the finer and coarser ends of this range are very different.