What are chemicals called that cause very fine particles to clump together into larger particles?

The term for chemicals that cause very fine particles to clump together into larger particles is "coagulants." Coagulation is a crucial process in water treatment where coagulants, such as aluminum sulfate or ferric chloride, are added to water to facilitate the aggregation of suspended particles, making them easier to remove during subsequent treatment steps.

When coagulants are introduced into a suspension of fine particles, they neutralize the electrical charges that keep these particles separated. This charge neutralization allows the fine particles, which are typically stabilized and suspended due to their surface charges, to come together and form larger aggregates known as flocs. Once these flocs are formed, they can be more easily removed from the water through sedimentation or filtration processes.

In this context, while flocculants are also involved in the aggregation of particles, they function typically in the later stage of the treatment process by promoting the growth of flocs formed during coagulation. Flocculators refer to the equipment used for mixing and enhancing the floc formation, and suspensions describe a mixture where particles are dispersed in a fluid but have not undergone the coagulation process. Thus, the terminology clearly distinguishes coagulants as the primary agents that initiate the clumping together