SIFTING, FLUIDIZATION, DUSTING SEGREGATION TENDENCIES

Segregation results when particles separate due to differences in their size, shape, or density. Bulk solids can segregate by a variety of mechanisms such as sifting segregation, fluidization segregation, and dusting.

With sifting segregation, the fine particles concentrate under the point of impact in a pile, while the coarse particles roll off the pile and locate at the periphery (yielding a side-to-side separation). Fluidization segregation results when fine particles in an aerated powder locate towards the top of a container, while the coarse particles deaerate quickly and settle to the bottom of a container (yielding a top-to-bottom separation). Dusting segregation occurs when the fine, dusty component of a blend concentrates in particular locations within a vessel, typically at the walls.

Sifting and fluidization segregation tendencies can be estimated via bench-scale tests described in ASTM protocols D6940 and D6941. Jenike & Johanson can measure these tendencies, and samples collected can be analyzed for particle size distribution by us and returned to your laboratory for chemical analysis or other specialized test.

Segregation tests run include:

Sifting segregation – side-to-side mechanism of segregation Fluidization segregation – top-to-bottom mechanism of segregation Sieve cut potency – powder separated by sieving for assay at each size cut

We also have the unique capability to perform sifting and fluidization segregation tests with our material sparing segregation testers. It is common in the pharmaceutical industry to have limited sample quantity for analysis, thus, we have developed the material sparring segregation testers to measure particle segregation tendencies with sample volumes of 10 ml and 50 ml for fluidization and sifting, respectively.