Difference between revisions of "Diatomaceous earth" - New World Encyclopedia

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[[Image:Mineraly.sk - diatomit.jpg|right|thumb|250px|A sample of diatomaceous earth]]
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[[Image:Mineraly.sk - diatomit.jpg|right|thumb|250px|A sample of diatomaceous earth.]]
  
'''Diatomaceous earth''' ([[International Phonetic Alphabet|IPA]]: {{IPA|/ˌdʌɪətəˈmeɪʃəs ˈəː(r)θ/}}, also known as '''DE''', '''diatomite''', '''diahydro''', '''kieselguhr''', '''kieselgur''' and '''Celite''') is a naturally occurring, soft, [[chalk]]-like sedimentary [[rock (geology)|rock]] that is easily crumbled into a fine white to off-white powder. This powder has an [[abrasive]] feel, similar to [[pumice]] powder, and is very light, due to its high [[porosity]]. The typical chemical composition of diatomaceous earth is 86% [[silica]], 5% [[sodium]], 3% [[magnesium]] and 2% [[iron]].
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'''Diatomaceous earth''' (also known as '''DE''', '''diatomite''', '''diahydro''', '''kieselguhr''', '''kieselgur''', and '''celite''') is a soft, [[chalk]]-like sedimentary [[rock (geology)|rock]]. It consists of the fossilized remains of [[diatom]]s, a type of hard-shelled [[algae]]. White to off-white in color, it is easily crumbled into a fine powder. The powder is highly [[porosity|porous]] and very light, and it has an [[abrasive]] feel, similar to [[pumice]] powder.
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Diatomaceous earth is useful for many applications. It is used as a [[filtration]] aid, mild [[abrasive]], [[absorbent]] for liquids, and [[insecticide]]. It is a component of [[cat litter]] and [[dynamite]]. Given its resistance to heat, it can be used as a [[thermal insulation|thermal insulator]].
  
Diatomaceous earth consists of fossilized remains of [[diatom]]s, a type of hard-shelled [[algae]]. It is used as a [[filtration]] aid, as a mild abrasive, as a mechanical [[insecticide]], as an [[absorbent]] for liquids, as [[cat litter]], as an activator in [[blood clotting]] studies, and as a component of [[dynamite]]. As it is also heat-resistant, it can be used as a [[thermal insulation|thermal insulator]].
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== Occurrence and characteristics ==
  
== Characteristics ==
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Given that diatomite is produced from the remains of waterborne [[diatom]]s, it is found close to current and former bodies of [[water]]. Based on the source, it is divided into two general categories: [[freshwater]] and [[Seawater|saltwater]]. Freshwater diatomite is mined from dry lakebeds and is characteristically low in its content of [[crystal]]line silica. By contrast, saltwater diatomite contains a high content of crystalline silica, making it a useful material for filters, due to the sieve-like features of the crystals.
<<Section needs more details>>
 
  
Because diatomite forms from the remains of water-borne [[diatom]]s, it is found close to either current or former bodies of water. It is generally divided into two categories based upon source: [[freshwater]] and [[Seawater|saltwater]]. Freshwater diatomite is mined from dry lakebeds and is characteristically low in [[crystal]]line silica content. Saltwater diatomite contains a high crystalline silica content, making it a useful material for filters, due to the sieve-like features of the crystals.
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Diatomite is highly porous, because it is composed of microscopically small, [[coffin]]-like hollow particles. In addition, it is a good absorbent and is resistant to heat. Its typical chemical composition is 86 percent [[silica]], five percent [[sodium]], three percent [[magnesium]], two percent [[iron]], and other minor constituents.
  
 
== Specific varieties ==
 
== Specific varieties ==
  
*'''TripoliteDakine''' is the variety found in [[Tripoli]], [[Libya]].
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Several varieties of diatomite have been found. They include the following types.
*'''Bann clay''' is the variety found in the [[River Bann|Lower Bann valley]] in [[Northern Ireland]].
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*'''Moler''' ('''Mo-clay''') is the variety found in northwestern [[Denmark]], especially on the islands of [[Fur (island)|Fur]] and [[Mors (island)|Mors]].
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* ''TripoliteDakine:'' This variety is found in [[Tripoli]], [[Libya]].
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* ''Bann clay:'' This variety is found in the [[River Bann|Lower Bann valley]] in [[Northern Ireland]].
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* ''Moler'' ''(Mo-clay)'': This variety is found in northwestern [[Denmark]], especially on the islands of [[Fur (island)|Fur]] and [[Mors (island)|Mors]].
  
 
== Applications ==
 
== Applications ==
 
=== Filtration ===
 
=== Filtration ===
  
The most common use (68%) of diatomaceous earth is as a [[filter (chemistry)|filter]] medium, especially for [[swimming pools]]. It has a high porosity, because it is composed of microscopically-small, [[coffin]]-like, hollow particles. It is used in [[chemistry]], as a filtration aid, to filter very fine particles that would otherwise pass or clog [[filter paper]]. It is also used to filter [[water]], particularly in the [[drinking water]] treatment process, and other liquids, such as [[beer]]. It can also filter syrups and sugar. Other industries such as paper, paints, ceramics, soap and detergents use it as a fulling material.
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Given its high porosity, diatomaceous earth is most commonly used (65-70 percent) as a [[filter (chemistry)|filter]] medium, especially for [[swimming pools]]. It is a filtration aid in [[chemistry]], to separate very fine particles that would otherwise pass or clog [[filter paper]]. It is also used to filter [[water]], particularly in the [[drinking water]] treatment process, and other liquids, such as [[beer]]. It can also filter syrups and sugar. Other industries such as paper, paints, ceramics, soap, and detergents use it as a fulling material.
  
 
=== Abrasive ===
 
=== Abrasive ===
  
The oldest use of diatomite is as a very mild abrasive and, for this purpose, it has been used both in [[toothpaste]] and in metal [[Polishing|polishes]], as well as in some facial scrubs.
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The oldest use of diatomite is as a mild abrasive. This application includes its use in [[toothpaste]], metal [[Polishing|polishes]], and some facial scrubs.
  
 
===Pest control===
 
===Pest control===
  
Diatomite is also used as an [[insecticide]], due to its physico-[[sorptivity|sorptive]] properties. The fine powder absorbs lipids from the [[Exoskeleton|cuticle]], the waxy outer layer of insects' exoskeletons, causing them to dehydrate. [[Arthropod]]s die as a result of the water pressure deficiency, based on [[Fick's law of diffusion]]. This also works against [[gastropod]]s and is commonly employed in gardening to defeat [[slug]]s. However, since slugs inhabit humid environments, efficacy is very low. [[Beekeeping|Beekeepers]] are apparently experimenting with it, to keep [[small hive beetle]]s from breeding. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Medical grade diatomite is sometimes used to de-worm both animals and humans. It is most commonly used in lieu of [[boric acid]], and can be used to help control and eventually eliminate a [[cockroach]] infestation.
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Diatomite is also used as an [[insecticide]], taking advantage of its physico-[[sorptivity|sorptive]] properties. The fine powder absorbs lipids from the [[Exoskeleton|cuticle]] (the waxy outer layer of insect exoskeletons), causing them to dehydrate. The lowering of water pressure kills [[arthropod]]s. This approach also works against [[gastropod]]s and is commonly employed to defeat garden [[slug]]s. However, since slugs inhabit humid environments, efficacy is very low. [[Beekeeping|Beekeepers]] are experimenting with it, to see if it will prevent [[small hive beetle]]s from breeding. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Medical-grade diatomite is sometimes used to de-worm animals and humans. It is also used to help control and eventually eliminate a [[cockroach]] infestation.
  
 
=== Absorbent ===
 
=== Absorbent ===
  
Its absorbent qualities make it useful for spill clean-up and the U.S. [[Center for Disease Control]] recommends it to clean up [[toxic]] liquid spills.  
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Its absorbent qualities make it useful for the cleanup of harmful spills. The U.S. [[Centers for Disease Control]] recommends it to clean up [[toxic]] liquid spills.
  
 
More recently, it has been employed as a primary ingredient in a type of cat litter. The type of silica used in cat litter comes from freshwater sources and does not pose a significant health risk to pets or humans.
 
More recently, it has been employed as a primary ingredient in a type of cat litter. The type of silica used in cat litter comes from freshwater sources and does not pose a significant health risk to pets or humans.
  
In 1867, [[Alfred Nobel]] discovered that [[nitroglycerin]] could be made much more stable if absorbed in diatomite. He patented this mixture as [[dynamite]], and the mixture is also referred to as guhr dynamite.
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In 1867, [[Alfred Nobel]] discovered that [[nitroglycerin]] (an explosive) could be made much more stable if absorbed in diatomite. He patented this mixture as [[dynamite]], also referred to as guhr dynamite.
  
=== Thermal ===
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=== Heat resistance ===
  
Its thermal properties enable it to be used as the barrier material in some fire resistant safes.
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Given its heat resistance, diatomite can be used as the barrier material in some fire-resistant safes.
  
 
=== Hydroponics ===
 
=== Hydroponics ===
Line 48: Line 51:
 
== Climatologic importance ==
 
== Climatologic importance ==
  
The Earth's [[climate]] depends greatly on the amount of [[dust]] in the [[atmosphere]], and hence, locating major sources of dust are of great interest for [[climatology]]. Recent research indicates that surface deposits of diatomaceous earth play a dominant resource here, a major example being the [[Bodélé depression]] in the part of the [[Sahara]] belonging to [[Chad]], where storms push diatomite gravel over [[dune]]s, where dust is abraded, leading to the largest single influx of dust into the atmosphere. <ref>Washington et al., Geophys. Res. Lett. ''33'' (2006) L09401 {{doi|10.1029/2006GL025827}}.</ref>
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The Earth's [[climate]] depends greatly on the amount of [[dust]] in the [[atmosphere]], and locating major sources of dust are of great interest for [[climatology]]. Recent research indicates that surface deposits of diatomaceous earth play a dominant role.
 +
 
 +
A major example is the [[Bodélé depression]] in a part of the [[Sahara]] belonging to [[Chad]]. Here, storms push diatomite gravel over [[dune]]s, and dust is abraded, leading to the largest single influx of dust into the atmosphere.<ref>R. Washington et al. [http://www.agu.org/pubs/crossref/2006/2006GL025827.shtml "Links between topography, wind, deflation, lakes and dust: The case of the Bodélé Depression, Chad."] ''Geophys. Res. Lett.'' 33, 2006. Retrieved November 13, 2007.</ref>
  
 
== Safety considerations ==
 
== Safety considerations ==
Line 56: Line 61:
 
The type of hazard posed by inhalation depends on the form of the silica. Crystalline silica poses a serious inhalation hazard because it can cause [[silicosis]]. Amorphous silica can cause dusty lungs, but does not carry the same degree of risk as crystalline silica. Food-grade diatomite generally contains very low percentages of crystalline silica. Diatomite produced for pool filters is treated with heat, causing the formerly amorphous silicon dioxide to assume its crystalline form.
 
The type of hazard posed by inhalation depends on the form of the silica. Crystalline silica poses a serious inhalation hazard because it can cause [[silicosis]]. Amorphous silica can cause dusty lungs, but does not carry the same degree of risk as crystalline silica. Food-grade diatomite generally contains very low percentages of crystalline silica. Diatomite produced for pool filters is treated with heat, causing the formerly amorphous silicon dioxide to assume its crystalline form.
  
In the [[United States]], the crystalline silica content in the dusts is regulated by the Occupational Safety and Health Administration (OSHA), and there are guidelines for the maximum amounts allowable in the product and in the air near the breathing zone of workers. <ref>[http://www.oznet.ksu.edu/grsc_subi/Teaching/GRSC651/GRSC651_Courses_Material/lecture_slides/GRSC651_lect_20(1)_Inert_Dusts.pdf Inert Dusts] at [[Kansas State University]].</ref>
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In the [[United States]], the crystalline silica content in the dusts is regulated by the Occupational Safety and Health Administration (OSHA), and there are guidelines for the maximum amounts allowable in the product and in the air near the breathing zone of workers.<ref>Bhadriraju Subramanyam and Rennie Roesli. [http://www.oznet.ksu.edu/grsc_subi/Teaching/GRSC651/GRSC651_Courses_Material/lecture_slides/GRSC651_lect_20(1)_Inert_Dusts.pdf "Inert Dusts."] ''Dept. of Grain Science and Industry, [[Kansas State University]]''. Retrieved November 13, 2007.</ref>
  
 
== See also ==
 
== See also ==
  
* [[Biomineralization]]
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* [[Abrasive]]
 
* [[Diatom]]
 
* [[Diatom]]
* [[Fuller's Earth]]
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* [[Dynamite]]
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* [[Filtration]]
 
* [[Perlite]]
 
* [[Perlite]]
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* [[Silica]]
  
 
== Notes ==
 
== Notes ==
Line 69: Line 76:
  
 
==References==
 
==References==
 +
* Founie, Alan. [http://minerals.usgs.gov/minerals/pubs/commodity/diatomite/ Minerals Information: Diatomite] ''U.S. Geological Survey''. 2007. Retrieved July 9, 2020.
 +
* Scharabok, Ken. The many uses of diatomaceous earth. ''Countryside & Small Stock Journal''. 83 (July 1999): 96.
 +
* Tucker, Maurice E. ''Sedimentary Petrology''. 3rd ed. Malden, MA: Blackwell Publishing, 2001. ISBN 0632057351
  
* [http://minerals.usgs.gov/minerals/pubs/commodity/diatomite/ Minerals Information: Diatomite.] ''U.S. Geological Survey''. Retrieved May 14, 2007.
+
== External links ==
 +
All links retrieved July 28, 2022.
 +
* [http://www.mindat.org/min-9855.html Diatomaceous Earth] ''Mindat.org''.  
  
== External links ==
 
  
* [http://www.ppearth.com/ Diatomaceous Earth in India]
 
* [http://minerals.usgs.gov/minerals/pubs/commodity/diatomite/ Diatomite: Statistics and Information - USGS]
 
* [http://www.mindat.org/min-9855.html Tripolite: Tripolite mineral data] Citat: "...A diatomaceous earth consisting of opaline silica..."
 
* [http://www.eap.mcgill.ca/Publications/eap4.htm DIATOMACEOUS EARTH: A Non Toxic Pesticide]
 
* [http://www.loughneagh.com/diatomite.htm The Lough Neagh & Lower Bann Advisory Committees: Diatomite] Quote: "...Diatomite, or Bann clay as it is known locally..."
 
* [http://www.geographyinaction.co.uk/Assets/Photo_albums/One/pages/Diatomite_jpg.html Photograph of diatomite deposits along River Bann, Ireland]
 
* [http://www.poultryyouth.com/articles/article-21/ Raising Poultry using Diatomacious Earth] - Article by the Poultry Youth Association
 
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]

Revision as of 03:19, 29 July 2022

A sample of diatomaceous earth.

Diatomaceous earth (also known as DE, diatomite, diahydro, kieselguhr, kieselgur, and celite) is a soft, chalk-like sedimentary rock. It consists of the fossilized remains of diatoms, a type of hard-shelled algae. White to off-white in color, it is easily crumbled into a fine powder. The powder is highly porous and very light, and it has an abrasive feel, similar to pumice powder.

Diatomaceous earth is useful for many applications. It is used as a filtration aid, mild abrasive, absorbent for liquids, and insecticide. It is a component of cat litter and dynamite. Given its resistance to heat, it can be used as a thermal insulator.

Occurrence and characteristics

Given that diatomite is produced from the remains of waterborne diatoms, it is found close to current and former bodies of water. Based on the source, it is divided into two general categories: freshwater and saltwater. Freshwater diatomite is mined from dry lakebeds and is characteristically low in its content of crystalline silica. By contrast, saltwater diatomite contains a high content of crystalline silica, making it a useful material for filters, due to the sieve-like features of the crystals.

Diatomite is highly porous, because it is composed of microscopically small, coffin-like hollow particles. In addition, it is a good absorbent and is resistant to heat. Its typical chemical composition is 86 percent silica, five percent sodium, three percent magnesium, two percent iron, and other minor constituents.

Specific varieties

Several varieties of diatomite have been found. They include the following types.

  • TripoliteDakine: This variety is found in Tripoli, Libya.
  • Bann clay: This variety is found in the Lower Bann valley in Northern Ireland.
  • Moler (Mo-clay): This variety is found in northwestern Denmark, especially on the islands of Fur and Mors.

Applications

Filtration

Given its high porosity, diatomaceous earth is most commonly used (65-70 percent) as a filter medium, especially for swimming pools. It is a filtration aid in chemistry, to separate very fine particles that would otherwise pass or clog filter paper. It is also used to filter water, particularly in the drinking water treatment process, and other liquids, such as beer. It can also filter syrups and sugar. Other industries such as paper, paints, ceramics, soap, and detergents use it as a fulling material.

Abrasive

The oldest use of diatomite is as a mild abrasive. This application includes its use in toothpaste, metal polishes, and some facial scrubs.

Pest control

Diatomite is also used as an insecticide, taking advantage of its physico-sorptive properties. The fine powder absorbs lipids from the cuticle (the waxy outer layer of insect exoskeletons), causing them to dehydrate. The lowering of water pressure kills arthropods. This approach also works against gastropods and is commonly employed to defeat garden slugs. However, since slugs inhabit humid environments, efficacy is very low. Beekeepers are experimenting with it, to see if it will prevent small hive beetles from breeding. It is sometimes mixed with an attractant or other additives to increase its effectiveness. Medical-grade diatomite is sometimes used to de-worm animals and humans. It is also used to help control and eventually eliminate a cockroach infestation.

Absorbent

Its absorbent qualities make it useful for the cleanup of harmful spills. The U.S. Centers for Disease Control recommends it to clean up toxic liquid spills.

More recently, it has been employed as a primary ingredient in a type of cat litter. The type of silica used in cat litter comes from freshwater sources and does not pose a significant health risk to pets or humans.

In 1867, Alfred Nobel discovered that nitroglycerin (an explosive) could be made much more stable if absorbed in diatomite. He patented this mixture as dynamite, also referred to as guhr dynamite.

Heat resistance

Given its heat resistance, diatomite can be used as the barrier material in some fire-resistant safes.

Hydroponics

Freshwater diatomite can be used as a growing medium in hydroponic gardens.

Climatologic importance

The Earth's climate depends greatly on the amount of dust in the atmosphere, and locating major sources of dust are of great interest for climatology. Recent research indicates that surface deposits of diatomaceous earth play a dominant role.

A major example is the Bodélé depression in a part of the Sahara belonging to Chad. Here, storms push diatomite gravel over dunes, and dust is abraded, leading to the largest single influx of dust into the atmosphere.[1]

Safety considerations

The absorbent qualities of diatomite can result in a significant drying of the hands, if handled without gloves. The saltwater (industrial) form contains a highly crystalline form of silica, resulting in sharp edges. The sharpness of this version of the material makes it dangerous to breathe and a dust mask is recommended when working with it.

The type of hazard posed by inhalation depends on the form of the silica. Crystalline silica poses a serious inhalation hazard because it can cause silicosis. Amorphous silica can cause dusty lungs, but does not carry the same degree of risk as crystalline silica. Food-grade diatomite generally contains very low percentages of crystalline silica. Diatomite produced for pool filters is treated with heat, causing the formerly amorphous silicon dioxide to assume its crystalline form.

In the United States, the crystalline silica content in the dusts is regulated by the Occupational Safety and Health Administration (OSHA), and there are guidelines for the maximum amounts allowable in the product and in the air near the breathing zone of workers.[2]

See also

Notes

  1. R. Washington et al. "Links between topography, wind, deflation, lakes and dust: The case of the Bodélé Depression, Chad." Geophys. Res. Lett. 33, 2006. Retrieved November 13, 2007.
  2. Bhadriraju Subramanyam and Rennie Roesli. "Inert Dusts." Dept. of Grain Science and Industry, Kansas State University. Retrieved November 13, 2007.

References
ISBN links support NWE through referral fees

  • Founie, Alan. Minerals Information: Diatomite U.S. Geological Survey. 2007. Retrieved July 9, 2020.
  • Scharabok, Ken. The many uses of diatomaceous earth. Countryside & Small Stock Journal. 83 (July 1999): 96.
  • Tucker, Maurice E. Sedimentary Petrology. 3rd ed. Malden, MA: Blackwell Publishing, 2001. ISBN 0632057351

External links

All links retrieved July 28, 2022.

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