The conversion of a colloid to a precipitate is known as coagulation or precipitation. Coagulation results in the removal of charges on the colloid by any one of the following:
- Addition of electrolytes
- electrophoresis
- mixing oppositely charged sols
- boiling.
These methods help remove charges from the particles. Thus, the particles come closer, form an aggregate of particles and finally settles down as a precipitate due to gravity.