Division of fire dust particles

The colour of fire dust 10.3 The division of fire dust particles... 

A single particle of the fire dust is a mixture of liquid and solid substances and has cohesion. When a strong wind blows against the particle, it is divided into many smaller particles by the occurrence of a spray-like phenomenon. This is called fire division". 

The fire division occurs most easily when the cohesion of the particle is weakest. With the fire dust of black pov/der-type compositions the point may be a content of about 7% sulphur. If the sulphur content is larger than that, the potassium sulfide, KiSx. content,in a particle increases to produce strong cohesion, which makes the fire division more difficult. If the content is less than that, unburned charcoal aggregates and in this case the fire division is also difficult. 

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