See more Perlite articles on AOD.

Powered by
Share this page on
Article provided by Wikipedia

( => ( => ( => Perlite [pageid] => 48668 ) =>
Expanded perlite

Perlite is an "amorphous "volcanic glass that has a relatively high "water content, typically formed by the hydration of "obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is an "industrial mineral and a commercial product useful for its low density after processing.



Perlite boulders with "fireweed in foreground

Perlite softens when it reaches temperatures of 850–900 °C (1,560–1,650 °F). Water trapped in the structure of the material vaporises and escapes, and this causes the expansion of the material to 7–16 times its original volume. The expanded material is a brilliant white, due to the reflectivity of the trapped bubbles. Unexpanded ("raw") perlite has a "bulk density around 1100 kg/m3 (1.1 g/cm3), while typical expanded perlite has a bulk density of about 30–150 kg/m3 (0.03-0.150 g/cm3).[1]

Typical analysis of perlite[edit]

Production and uses[edit]

Perlite output in 2005
Perlite mine in Owens Valley, California.

Perlite is a non-renewable resource. The world reserves of perlite are estimated at 700 million "tonnes. In 2011, 1.7 million tonnes were produced, mostly by Greece (500,000 t), United States (375,000 t) and Turkey (220,000 t). However, no information for China – a leading producer – was available.[3] As of 2003, Greece was a leader in processed perlite production; however, estimates of perlite production from the report USGS Mineral Commodity Summaries 2013 indicate that the U.S. may have overtaken Greece.[4]

Because of its low density and relatively low price (about US$50 per tonne of unexpanded perlite), many commercial applications for perlite have developed. In the "construction and manufacturing fields, it is used in lightweight "plasters, concrete and "mortar (masonry), "insulation and ceiling tiles.[5] In "horticulture, perlite can be used as a "soil amendment or alone as a medium for "hydroponics or for starting "cuttings. When used as an amendment it has high permeability / low water retention and helps prevent "soil compaction.[6] Perlite is an excellent "filtration aid and is used extensively as an alternative to "diatomaceous earth. The popularity of perlite usage as a filter medium is growing considerably worldwide. Perlite filters are fairly commonplace in filtering "beer before it is bottled.

Small quantities of perlite are also used in "foundries, "cryogenic insulation, and in "ceramics as a clay additive. It is also used by the explosives industry.[7] Due to thermal and mechanical stability, non-toxicity, and high resistance against microbial attacks and organic solvents, perlite is widely used in biotechnological applications. Perlite was found to be an excellent support for immobilization of biocatalysts such as enzymes for "bioremediation and sensing applications.[8]


Perlite can be substituted for all of its uses. Substitutes include:[4]


Occupational safety[edit]

People can be exposed to perlite in the workplace by breathing in dust, skin contact, and eye contact.

United States[edit]

The "Occupational Safety and Health Administration (OSHA) has set the legal limit ("permissible exposure limit) for perlite exposure in the workplace as 15 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday. The "National Institute for Occupational Safety and Health (NIOSH) has set a "recommended exposure limit (REL) of 10 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday.[13]

See also[edit]


  1. ^ Maxim, L. Daniel; Niebo, Ron; McConnell, Ernest E. (2014-04-01). "Perlite toxicology and epidemiology – a review". Inhalation Toxicology. 26 (5): 259–270. "doi:10.3109/08958378.2014.881940. "ISSN 0895-8378. "PMC 4002636Freely accessible. "PMID 24601903. 
  2. ^ Md Arifuzzaman and H. S. Kim, “Prediction and evaluation of density and volume fractions for the novel perlite composite affected by internal structure formation”, Construction and Building Materials, Vol 141, 2017, 201-215.
  3. ^ a b Perlite, USGS Mineral Commodity Summaries 2011
  4. ^ a b USGS Mineral Commodity Summaries (PDF), 2013 
  5. ^ a b c Wallace P. Bolen Perlite USGS 2009 Minerals Yearbook
  6. ^ "ISU Extension News Release". 
  7. ^ Emulsion explosive composition containing expanded perlite United States Patent 4940497
  8. ^ Torabi, Seyed-Fakhreddin; Khajeh, Khosro; Ghasempur, Salehe; Ghaemi, Nasser; Siadat, Seyed-Omid Ranaei (2007-08-31). "Covalent attachment of cholesterol oxidase and horseradish peroxidase on perlite through silanization: Activity, stability and co-immobilization". Journal of Biotechnology. 131 (2): 111–120. "doi:10.1016/j.jbiotec.2007.04.015. 
  9. ^ "PERLITE : (Data in thousand metric tons unless otherwise noted)" (PDF). Retrieved 22 October 2017. 
  10. ^ "Perlite" (PDF). U.S. Geological Survey Mineral Commodity Summaries: 122–123. January 2006. 
  11. ^ Dipendra Shastri and H. S. Kim, “A new consolidation process for expanded perlite particles”, Construction and Building Materials, Vol 60, June, 2014, pp.1-7.
  12. ^ Md Arifuzzaman and H. S. Kim, Novel flexural behaviour of sandwich structures made of perlite foam/sodium silicate core and paper skin, Construction and Building Materials, Construction and Building Materials, Vol 148 2017, pp 321–333.
  13. ^ "CDC - NIOSH Pocket Guide to Chemical Hazards - Perlite". Retrieved 2015-11-27. 

External links[edit]

) )