Flocculation, in the field of chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

, is a process wherein colloids come out of suspension
Suspension (chemistry)
In chemistry, a suspension is a heterogeneous fluid containing solid particles that are sufficiently large for sedimentation. Usually they must be larger than 1 micrometer. The internal phase is dispersed throughout the external phase through mechanical agitation, with the use of certain...

 in the form of floc or flakes by the addition of a clarifying agent
Clarifying agent
-Process:Particles finer than 0.1 µm in water remain continuously in motion due to electrostatic charge which causes them to repel each other. Once their electrostatic charge is neutralized by the use of coagulant chemical, the finer particles start to collide and agglomerate under the...

. The action differs from precipitation
Precipitation (chemistry)
Precipitation is the formation of a solid in a solution or inside anothersolid during a chemical reaction or by diffusion in a solid. When the reaction occurs in a liquid, the solid formed is called the precipitate, or when compacted by a centrifuge, a pellet. The liquid remaining above the solid...

 in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...

. In the flocculated system, there is no formation of a cake, since all the flocs are in the suspension.
According to the IUPAC definition, flocculation is "a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters." Flocculation is synonymous with agglomeration
Particle aggregation
Particle aggregation in materials science is direct mutual attraction between particles via van der Waals forces or chemical bonding....

, aggregation, and coagulation
Coagulation (disambiguation)
Coagulation may refer to:* Coagulation, in colloid chemistry, a process in which dispersed colloidal particles agglomerate. See flocculation* Coagulation of blood* Coagulation , the coagulation of milk into curd by rennet or acid...

 / coalescence
Coalescence (chemistry)
In chemistry, coalescence is a process in which two phase domains of the same composition come together and form a larger phase domain.-References:*...