Hi Justin: Coagulation is ...

Hi Justin:

Coagulation is the addition and rapid mixing of a coagulant, the resulting destabilization of colloidal and fine suspended solids and initial aggregation of the destabilized particles.

But, Flocculation is the next process after the Coagulation and is the slow stirring or gentle agitation to aggregate the destabilized particles and form a rapid settling flocs. 

The second point is that the Coagulation is chemical conditioning of colloids, but Flucculation is physical conditioning of colloids and complete the Coagulation process.