Novel atomizing methods for powder production of non-ferrous metals

The demand for non-ferrous metal powders of higher quality, and produced with better control and lower costs, has lead to a demand for improved melt atomization techniques to be developed. The Russian company URALNETRAMM and the English company ATOMISING SYSTEMS Ltd have cooperated in the development of new methods to produce powders of Sn, Pb, Zn, Mg, Cu-Sn and other alloys with special properties, particularly narrow size range and fine particle size, while using very small amounts of atomizing medium and energy. The centrifugal-hydraulic atomization method(CHA) is a single-fluid atomization process using the energy of the fluid to atomize it in a swirljet (hollow cone) nozzle. This method allows the production of powders from 100 mkm up to 1000 mkm with a standard deviation of the particle size distribution of 1.4-1.6 with outputs from 50 kg up to several tonnes per hour. Combining the swirljet nozzle design with internal gas injection, to give an internal mixing gas atomizer allows the production of very fine powders from 15-20 mk using less than one tenth the amoumt of gas normally used for gas atomization (eg 0.1 cu m/kg). We call this method centrifugal-pneumatic atomization (CPA). This paper introduces these technologies and discusses the properties of powders produced by them.