Deflocculation
A deflocculant is a chemical additive to prevent a colloid from coming out of suspension or to thin suspensions or slurries. It is used to reduce viscosity or prevent flocculation and is sometimes incorrectly called a "dispersant." Most deflocculants are low-molecular-weight anionic polymers that neutralize positive charges on suspended particles, in particular clays and aryl-alkyl derivative of sulfonic acid. Examples include polyphosphates, lignosulfonates, quebracho tannins, and various water-soluble synthetic polymers.
Deflocculation is also used to describe the undesired effect in an activated sludge basin if the sludge is subjected to high-speed mixing. In general, deflocculation can be prevented or reduced by applying gentle mixing (e.g., by using submersible propeller mixers that utilize large/wide propeller blades and operate at low rotational speed).
Read more about this topic: Flocculation