Ejectants

An ejectant is an agent that promotes the ejection, release, or removal of a material from a system. The term appears in several technical fields but has no universal, fixed definition. Ejectants can be gases, liquids, or solids, and they work by various mechanisms. Physical mechanisms include generating pressure, flowing to physically push a component away, or reducing adhesion between surfaces to ease release. Chemical mechanisms involve reactions or phase changes that produce gas, lower interfacial energy, or otherwise weaken binding, enabling ejection.

In manufacturing and materials processing, ejectants are used to facilitate demolding, separation, or cleaning. For example, a mold-release ejectant reduces sticking between a molded part and its mold. In separation sciences, a fluid phase sometimes described as an ejectant serves to carry away products or impurities—though the standard term in most contexts is eluent, solvent, or purge gas.

In surface science and catalysis, ejectants may refer to gas streams that remove surface-bound species during cleaning or regeneration steps. Ejectants can be designed to minimize residue, control timing, or be easily removed after use.

Etymology: from eject, to throw out. Because usage varies by field, precise definitions are tied to context; when high precision is required, more specific terms such as mold release agent, eluent, purge gas, or solvent are preferred.