Variables that can affect the tendency of particles to segregate include

• Particle size distribution and shape: Sifting segregation is most likely to occur when the material has a range of particle sizes and when there is interparticle motion during operation. Generally, particles greater than about 100 /'m in diameter are most susceptible to sifting segregation. If most of the particles are smaller than 100 /'m, segregation is more likely to occur by air or particle entrainment.

• Cohesiveness: The more cohesive a material, the less likely it is to segregate. Thus, for some materials, the potential for segregation can be reduced by adding binders. In general, this makes the material less free-flowing and causes fine particles to stick to coarse ones. Caution is advised, however, because the additive can rapidly change a situation from one of free flow to one of no flow.

• Bin flow pattern: The type of flow pattern that develops can significantly affect the segregation tendency of materials. Typically, funnel flow patterns exacerbate side-to-side segregation (such as that caused by sifting), whereas a mass flow pattern tends to minimize such problems.

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