Refinement (metal)

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In metallurgy, refining , like separating (cf. Scheideanstalt für Affinerie ), is an outdated term for the designation of separation processes with which elements can be separated from one another or solutions and other mixtures can be divided into their components ( mixture separation ). When smelting of ores and metals unwanted components from the melt must often be removed.

Method of purification

Driving work
Classic technology that was used in prehistoric times. The silver was driven out of lead ores containing silver in the forcing hearth. Today also known as cupellation .
Filtration
Solid substances are mechanically separated from liquid or gaseous components in that the mass is pressed through a porous material (e.g. textiles) that retains the solid components and lets the liquid or gaseous pass through.
Centrifuge
Two substances, of which at most one may be solid, are separated from one another by a density gradient .
evaporation
Two liquids are separated from each other by heating as soon as both have a different boiling point.
extraction
Extraction (Latin extractio , to extrahere “to pull out”) is a physical material separation process in which a component is dissolved from a mixture of substances with the help of an extraction agent (a - if necessary heated - solvent). The “solvent” draws the substance that is more soluble in it from the mixture.
Crystallization
Crystallization is a solidification process that leads to the formation of crystals. It can come from a solution, a melt, the gas phase, an amorphous solid or from another crystal (recrystallization), but always through crystal formation and crystal growth (single crystal) - a process that releases heat of crystallization.
adsorption
In the process of adsorption (lat. Adsorptio to adsorbere "draw") is superimposed on an atom or molecule from a gas or a liquid to a surface of the adsorbent : (plural adsorbents on).
smelting
By heating and parallel reduction of ores, the metallic components are separated from the gangue, either semi-solid (doughy) like sponge iron or melted out.
electrolysis
Electrolysis, also known as fused flux electrolysis , allows electric current to flow in a solution or a molten flux between an anode and a cathode, for example to extract metals from aqueous solutions or to reverse chemical reactions. According to this principle, cathode copper (also called electrolytic copper) is produced or oxygen and hydrogen are obtained from water.

literature

  • Jean-Baptiste Dumas: Handbook of Applied Chemistry. Volume 4, by Johann Leonhard Schrag, Nuremberg 1835.
  • Franz Luckenbacher, Karl de Roth, Julius Zoellner: The chemical treatment of raw materials. 7th edition, Springer Verlag Berlin Heidelberg GmbH, Berlin Heidelberg 1877.

See also

Web links