Scaling-down problem in binary spray pulverisation of molten metals

The production capacities of plants for metal pulverisation are frequently rated according to the minimum throughput of melt flowing from the distributor crucible to pulverisation. Especially in the case of high-melting point metals and their alloys deficiencies occur in the thermal balance of the crucible in the exit section as a result of gas expansion at the pulverisation gas jets, which act as heat sinks, Minimum throughputs and associated limiting values of the convective heat transfer of the melt are stipulated in order to prevent "freezing" (solidification of the melt) in the crucible, The pertinent situation is illustrated for copper and steel melts and technical possibilities for compensating for heat deficiencies by inductive heating of the distributor exit are presented. In addition, the demand for minimum throughputs can be abandoned, and there result possibilities of scaling-down and energy conservation as well as improvement of powder discharge.