Diatomaceous earth

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Diatomites

Description

An absorbent powder composed of the siliceous skeletons of microscopic water plants called diatoms. Diatomaceous earth is composed of 88% silica. The soft, whitish material is used as an inert pigment or filler in paper, paint, brick, floor tiles, ceramics, linoleum, plastic, soap, detergent, and a large number of other products. It reduces gloss, acts as a suspending agent, and increases viscosity. It absorbs dyes well and has been used as a base for lake colors. Diatomaceous earth is also used as an absorbent, and poultice since it can absorb up to 4 times its weight of water. Because of its water-absorption capabilities, it is used as a desiccating insecticide and is often mixed in formulations with pyrethrins. Diatomaceous earth has also been used as a decolorizer and filtration aid for purifying oils, fats, and waxes. Diatomaceous earth has replaced asbestos as an insulation for boilers, blast furnaces, because it is more resistant to shrinkage and does not fail at high temperatures. Other uses include sound insulation and as a very mild abrasive in metal polishes and toothpaste.

Diatomaceous earth

Synonyms and Related Terms

diatomite; poudre de diatomées (Fr.); tierra de diatomeas (Esp.); diatomito (Port.); Diatomeenerde, Kieselgur (Deut.); diatomeënaarde (Ned.); Celite® [Celite]; infusorial earth; kieselguhr; fossil flour; tripolite; Sil-O-Cel; diatomaceous silica; siliceous earth; Super-Cel; Kenite®; Diactiv®; Primisil®;

Other Properties

Soluble in alkalis. Insoluble in acids except HF.

Density 1.9-2.35
Refractive Index 1.435

Hazards and Safety

Inhalation of dust may cause silicosis. Noncombustible.

Diatomaceous earth

Comparisons

Properties of Common Abrasives


Sources Checked for Data in Record

  • The Dictionary of Paper, American Paper Institute, New York, Fourth Edition, 1980
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966 Comment: density 2.31 and ref.index.1.435
  • Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
  • Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p.266
  • Reed Kay, The Painter's Guide To Studio Methods and Materials, Prentice-Hall, Inc., Englewood Cliffs, NJ, 1983
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • J. Dawson, 'Solving Museum Insect Problems: Chemical Control' , CCI Technical Bulletin, Candian Conservation Institute, Ottawa, No. 15
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976