Atomisation of molten Zinc

Abstract

Zinc dust is produced by an atomisation process in which air at 17 atmospheres pressure is directed through a narrow annular nozzle surrounding a stream of molten zinc. Industrially, it is important to control the size distribution of zinc particles. It is therefore necessary to understand the features of the process, guided where appropriate by simple mathematical models and estimates. This report examines qualitative features using simple models for number of drops produced, estimates for air speed and swirl, heat transfer in the molten zinc and droplets, and droplet collisions and stability. Results from a literature survey are presented. At this stage, the construction of more elaborate mathematical models for the process is not warranted; rather, we expect that better understanding of the process requires an experimental program involving flow visualisation.