Heavy liquid

A heavy liquid is a solution or liquid chemical substance with a high density and a relatively low viscosity. Heavy liquids are often used for determination of density in mineralogy, for density gradient centrifugation and for separating mixtures.

This article is about chemicals. For the music album, see Heavy Liquid. For comics, see Heavy Liquid (comics).

Uses

Common applications of heavy liquids include:

  • Density gradient centrifugation
  • Separating mixtures and sink/swim analysis
  • Flotation process
  • Determination of density

Toxicity

The classical heavy liquids like 1,1,2,2-tetrabromoethane (Muthmanns solution), potassium tetraiodomercurate(II) (Thoulets solution), bromoform or diiodomethane which are used in mineralogy are very toxic. These toxic chemicals are avoided today in consideration of the fact that there are alternative water based, non-toxic heavy liquids like sodium polytungstate solutions.[1] With this relatively new heavy liquid densities up to 3.1 g·cm−3 can be adjusted . Adding parts of pulverulent Tungsten carbide increases the density to 4.6 g·cm−3.[2]

List of common heavy liquids with density > 2.0 g·cm−3
NameDensity in g·cm−3
1,2-Dibromoethane2.180
cis-1,2-Dibromoethene2.246
trans-1,2-Dibromoethene2.231
Dibromomethane2.477
Bromal2.550
Bromoform2.890
1,1,2,2-Tetrabromoethane (Muthmanns solution)2.967
Sodium polytungstate3.100
Bromine3.1028
Thoulets solution3.196
Diiodomethane3.325
Indiumiodide3.40
Bariummercuriciodide3.57
Thallium formate + Thallium malonate (Clerici solution)4.25
Liquid metal (Gallium/Indium/Tin/Zinc alloy)6.5
Mercury13.6

References
  1. Callahan J, A non-toxic heavy liquid and inexpensive filters for separation of mineral grains, in Journal of Sedimentary Petrology, 57/1987, S.765-6
  2. CD Römpp Chemie Lexikon – Version 1.0: Schwerflüssigkeiten, Georg Thieme Verlag, 1995

Literature
  • Schnitzer W, Zur Problematik der Schwermineralanalyse am Beispiel triassischer Sedimentgesteine, in International Journal of Earth Sciences, 72/1983, S.67–75, ISSN 1437-3254 (Print) 1437-3262 (Online)
  • Boenigk, Schwermineralanalyse, S.6–15, Stuttgart: Enke, 1983.
  • Ney, Gesteinsaufbereitung im Labor, S.92–113, Stuttgart: Enke, 1986.


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