Flocculation is considered an improvement, as often many irregularly-shaped molecules can join together to form a larger, and therefore heavier, near-spherical particle. Flocculation is usually used in terms of either polymers being joined, or very tiny particles, perhaps only a few microns in diameter, being linked. Autocoagulation is basically the same idea, only with particles that wouldn't normally coagulate, but due to ionic environmental features, are in fact clumping.