Case study of spontaneous heating of metal powder – Calorimetric solution

Abstract Two samples of mixed metal powders taken from one workplace of surface metallisation were studied with respect to self-heating risk. Irrespective of the similar chemical composition, one of the powders proved significantly increased reactivity in aerial oxygen resulting in self-heating occurrence in situ. As the main reason for the distinct behaviour of the samples, a difference in particle size distribution was found. From a technical point of view, the different grain size of the powders arose from the nonsymmetric branching of the suction piping.