Dispersibility or dustiness

Uniformity may also be defined from a sieve analysis. Uniformity is the ratio of the specific sieve size which allows 60% of the initial mass of particles to pass through the specific sieve size fo the sieve size, which allows only 10% of the initial mass of particles to pass. The smaller the ratio, the greater the uniformity of the powder. Powders with particle sizes above 50-100 xm tend to have greater flowability due to having less cohesiveness and more uniformity. 

Dustiness of a powder is its propensity to emit dust when undergoing stress in a process or handling operation. A wide variety of test methods exist, which range from the impact or a single drop test to fluidised beds and rotating drums. These and others have been reviewed by 

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