Coagulants

(coagulating agents), substances that cause coagulation—that is, adhesion of particles—when introduced into a fluid medium containing tiny particles. Large masses of cohering particles formed by coagulation are precipitated in the form of flakes or lumps (coagulum). The salts of polyvalent metals, such as aluminum and iron, are effective coagulants for systems with an aqueous dispersion medium. Macromolecular, water-soluble organic compounds (polymers), especially poly-electrolytes, are also used as coagulants. Unlike inorganic coagulants, they are sometimes called flocculants. Coagulants are used to separate commercially valuable products from the waste products of a variety of industrial processes and to eliminate natural and household pollutants from water.

In medicine, coagulants are agents that increase the coagulability of blood—for example, vicasol, gelatin solution, and some preparations obtained from blood (thrombin and fibrinogen).