Important Characteristics Of Flocculated Suspensions

Important Characteristics Of Flocculated
Suspensions

·  Particles in the suspension are in form of loose agglomerates.

·  Flocs are collection of particles, so rate of sedimentation is high.

·  The sediment is formed rapidly.

·  The sediment is loosely packed. Particles are not bounded tightly to each other. Hard cake is not formed.

·  The sediment is easily redispersed by small amount of agitation.

·  The flocculated suspensions exhibit plastic or pseudo plastic behavior.

·  The suspension is somewhat unsightly, due to rapid sedimentation and presence of an obvious clear supernatant region.

·  The pressure distribution in this type of suspension is uniform at all places, i.e. the pressure at the top and bottom of the suspension is same.

·  In this type of suspension, the viscosity is nearly same at different depth level.

·  The purpose of uniform dose distribution is fulfilled by flocculated suspension.

2.2.6 Important Characteristics Of Deflocculated
Suspensions

·  In this suspension particles exhibit as separate entities.

·  Particle size is less as compared to flocculated particles. Particles settle separately and hence, rate of settling is very low.

·  The sediment after some period of time becomes very closely packed, due to weight of upper layers of sedimenting materials.

·  After sediment becomes closely packed, the repulsive forces between particles are overcomed resulting in a non-dispersible cake.

·  More concentrated deflocculated systems may exhibit dilatant behavior.

·  This type of suspension has a pleasing appearance, since the particles are suspended
relatively longer period of time.

·  The supernatant liquid is cloudy even though majority of particles have been settled.

·  As the formation of compact cake in deflocculated suspension, Brookfield viscometer shows increase in
viscosity when the spindle moves to the bottom of the suspension.

·  There is no clear-cut boundary between sediment and supernatant.