Studies on the burning behaviour of metal powder fires and their extinguishment: Part 1 — Mg, Al, AlMg alloy powder fires on sand bed

Abstract

This paper presents burning behaviour studies on magnesium, aluminium and aluminium-magnesium alloy powders heaped on a sand bed under atmospheric conditions. The individual powder heaps were ignited by gently placing 2 g of burning magnesium powder in a small shallow cavity at the top of the powder heap. Analysis of results reveals that the measurement of temperature-time profiles within the powder heap, developed during burning, is a convenient way to characterize the burning behaviour of metal powder fires in the form of heap. This, coupled with DTA and TGA studies, and visual and photographic observations, helps to identify the probable movement of the burning front during combustion. On this basis it has been concluded that the burning behaviours of magnesium and aluminium-magnesium alloy powders are similar, but differ considerably from that of aluminium powder. Two important features have also emerged from these studies, i.e. the lifting of the edges of the heap in the cases of magnesium and aluminium-magnesium alloy powder fires, and the melting of aluminium after ignition during the burning.