Centrifugation in the context of "Centrifuge"

Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid, semi-solid or liquid. This process is often used as a final production step before selling or packaging products. To be considered "dried", the final product must be solid, in the form of a continuous sheet (e.g., paper), long pieces (e.g., wood), particles (e.g., cereal grains or corn flakes) or powder (e.g., sand, salt, washing powder, milk powder). A source of heat and an agent to remove the vapor produced by the process are often involved. In bioproducts like food, grains, and pharmaceuticals like vaccines, the solvent to be removed is almost invariably water. Desiccation may be synonymous with drying or considered an extreme form of drying.

In the most common case, a gas stream, e.g., air, applies the heat by convection and carries away the vapor as humidity. Other possibilities are vacuum drying, where heat is supplied by conduction or radiation (or microwaves), while the vapor thus produced is removed by the vacuum system. Another indirect technique is drum drying (used, for instance, for manufacturing potato flakes), where a heated surface is used to provide the energy, and aspirators draw the vapor outside the room. In contrast, the mechanical extraction of the solvent, e.g., water, by filtration or centrifugation, is not considered "drying" but rather "draining".

In chemistry, work-up refers to the series of manipulations required to isolate and purify the product(s) of a chemical reaction. The term is used colloquially to refer to these manipulations, which may include:

• deactivating any unreacted reagents by quenching a reaction.
• cooling the reaction mixture or adding an antisolvent to induce precipitation, and collecting or removing the solids by filtration, decantation, or centrifugation.
• changing the protonation state of the products or impurities by adding an acid or base.
• separating the reaction mixture into organic and aqueous layers by liquid-liquid extraction.
• removal of solvents by evaporation.
• purification by chromatography, distillation or recrystallization.

The work-up steps required for a given chemical reaction may require one or more of these manipulations. Work-up steps are not always explicitly shown in reaction schemes. Written experimental procedures will describe work-up steps but will usually not formally refer to them as a work-up.

Purification in a chemical context is the physical separation of a chemical substance of interest from foreign or contaminating substances. Pure results of a successful purification process are termed isolate. The following list of chemical purification methods should not be considered exhaustive.

• Affinity purification purifies proteins by retaining them on a column through their affinity to antibodies, enzymes, or receptors that have been immobilised on the column.
• Filtration is a mechanical method to separate solids from liquids or gases by passing the feed stream through a porous sheet such as a cloth or membrane, which retains the solids and allows the liquid to pass through.
• Centrifugation is a process that uses an electric motor to spin a vessel of fluid at high speed to make heavier components settle to the bottom of the vessel.
• Evaporation removes volatile liquids from non-volatile solutes, which cannot be done through filtration due to the small size of the substances.
• Liquid–liquid extraction removes an impurity or recovers a desired product by dissolving the crude material in a solvent in which other components of the feed material are soluble.
• Crystallization separates a product from a liquid feed stream, often in extremely pure form, by cooling the feed stream or adding precipitants that lower the solubility of the desired product so that it forms crystals. The pure solid crystals are then separated from the remaining liquor by filtration or centrifugation.
• Recrystallization: In analytical and synthetic chemistry work, purchased reagents of doubtful purity may be recrystallised, e.g. dissolved in a very pure solvent, and then crystallized, and the crystals recovered, in order to improve and/or verify their purity.
• Trituration removes highly soluble impurities from usually solid insoluble material by rinsing it with an appropriate solvent.
• Adsorption removes a soluble impurity from a feed stream by trapping it on the surface of a solid material, such as activated carbon, that forms strong non-covalent chemical bonds with the impurity.
• Chromatography employs continuous adsorption and desorption on a packed bed of a solid to purify multiple components of a single feed stream. In a laboratory setting, mixture of dissolved materials are typically fed using a solvent into a column packed with an appropriate adsorbent, and due to different affinities for solvent (moving phase) versus adsorbent (stationary phase) the components in the original mixture pass through the column in the moving phase at different rates, which thus allows to selectively collect desired materials out of the initial mixture.
• Smelting produces metals from raw ore, and involves adding chemicals to the ore and heating it up to the melting point of the metal.
• Refining is used primarily in the petroleum industry, whereby crude oil is heated and separated into stages according to the condensation points of the various elements.
• Distillation, widely used in petroleum refining and in purification of ethanol separates volatile liquids on the basis of their relative volatilities. There are several type of distillation: simple distillation, steam distillation etc.
• Water purification combines a number of methods to produce potable or drinking water.
• Downstream processing refers to purification of chemicals, pharmaceuticals and food ingredients produced by fermentation or synthesized by plant and animal tissues, for example antibiotics, citric acid, vitamin E, and insulin.
• Fractionation refers to a purification strategy in which some relatively inefficient purification method is repeatedly applied to isolate the desired substance in progressively greater purity.
• Electrolysis refers to the breakdown of substances using an electric current. This removes impurities in a substance that an electric current is run through
• Sublimation is the process of changing of any substance (usually on heating) from a solid to a gas (or from gas to a solid) without passing through liquid phase. In terms of purification - material is heated, often under vacuum, and the vapors of the material are then condensed back to a solid on a cooler surface. The process thus in its essence is similar to distillation, however the material which is condensed on the cooler surface then has to be removed mechanically, thus requiring different laboratory equipment.
• Bioleaching is the extraction of metals from their ores through the use of living organisms.

Separation process

Non-centrifugal cane sugar (NCS) is the technical name given to traditional raw sugar obtained by evaporating water from sugarcane juice. NCS is internationally recognized as a discrete and unique product by the FAO since 1964 and by the World Customs Organization (WCO) since 2007. WCO defines NCS as "cane sugar obtained without centrifugation". It also states that "the product contains only natural anhedral micro-crystals, of irregular shape, not visible to the naked eye, which are surrounded by molasses' residues and other constituents of sugar cane". NCS is produced in most sugarcane-growing regions of the world, being known by many different names such as panela, jaggery, or gur. Some varieties of muscovado are non-centrifugal.

Dewatering /diːˈwɔːtərɪŋ/ is the removal of water from a location. This may be done by wet classification, centrifugation, filtration, or similar solid-liquid separation processes, such as removal of residual liquid from a filter cake by a filter press as part of various industrial processes.

Construction dewatering, unwatering, or water control are common terms used to describe removal or draining groundwater or surface water from a riverbed, construction site, caisson, or mine shaft, by pumping or evaporation. On a construction site, this dewatering may be implemented before subsurface excavation for foundations, shoring, or cellar space to lower the water table. This frequently involves the use of submersible "dewatering" pumps, centrifugal ("trash") pumps, eductors, or application of vacuum to well points. The international business research company Visiongain valued the global dewatering pump market at $6.4 billion in 2018.