Industrial separation processes


Industrial separation processes are technical procedures which are used in industry to separate a product from impurities or other products. The original mixture may either be a natural resource or the product of a chemical reaction.

Significance

are of great economic importance as they are accounting for 40 – 90% of capital and operating costs in industry. The separation processes of mixtures are including besides others washing, extraction, pressing, drying, clarification, evaporation, crystallization and filtration. Often several separation processes are performed successively. Separation operations are having several different functions:
A heterogeneous mixture can be separated by mechanical separation processes like filtration or centrifugation. Homogeneous mixtures can be separated by molecular separation processes; these are either equilibrium-based or rate-controlled. Equilibrium-based processes are operating by the formation of two immiscible phases with different compositions at equilibrium, an example is distillation. Rate-controlled processes are based on different transport rates of compounds through a medium, examples are adsorption, ion exchange or crystallization.
Separation of a mixture into two phases can be done by an energy separating agent, a mass separating agent, a or external fields. Energy-separating agents are used for creating a second phase, they are the most common techniques used in industry. For example, leads the addition of heat to a liquid to the formation of vapor. Mass-separating agents are other chemicals. They selectively dissolve or absorb one of the products; they are either a liquid or a solid. The use of a barrier which restricts the movement of one compound but not of the other one is less common; external fields are used just in special applications.