Variables contributing to bulk powder properties

It must be realised, however, that it is not easy, with any degree of certainty, to predict the rate of flow of powder assemblies and agglomerates from orifices solely by static individual conditions. 

In order to aid the characterisation of an assembly of particles or bulk mass, knowledge of the distribution of the physical particle properties is required. Although distribution of particle size and recently particle shape can be readily obtained by laboratory instrumentation. 

The properties and phenomena associated with an assembly of particles and powder behaviour in processing are due to the combination of many individual particle and powdCT properties, some of which are listed below  

1 Particle size distribution and specific surface area 

This chapter will highlight the factors of packing (bulk density, voidage), rate of flow, compressibility of packing, flowability, failure properties and angle of internal friction, cohesion, strength and adhesion. The factors of particle size distribution, specific surface area and particle shape distribution have already been dealt with elsewhere (Stanley-Wood 2000, 2005). 

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