Fuller's earth
Encyclopedia
Fuller's earth is any non-plastic clay
or claylike earthy material used to decolorize, filter, and purify animal, mineral, and vegetable oils and greases.
In 2005, the United States was the largest producer of fuller's earth with an almost 70% world share followed at a distance by Japan and Mexico.
Fuller's earth usually has a high magnesium oxide
content. In the United States, two varieties of fuller's earth are mined, mainly in the southeastern states. These comprise the minerals montmorillonite
or palygorskite
(attapulgite) or a mixture of the two; some of the other minerals that may be present in fuller's earth deposits are calcite
, dolomite
, and quartz
.
In England, fuller's earth occurs mainly in the Lower Greensand
. It has also been mined in the Vale of White Horse
, Oxfordshire
, England
. The Combe Hay
Mine was a fuller's earth mine operating to the south of Bath, Somerset until 1979. Other sites south of Bath included Frome
, Lonsdale
, Englishcombe
Tucking Mill
and Duncorn Hill
. Although these sites had been used since Roman times William Smith
developed new methods for the identification of deposits of Fuller's earth to the south of Bath. Other English sources include a mine near Redhill, Surrey
(worked until 2000), and Woburn, Bedfordshire
, where production ceased in 2004.
In some countries calcium bentonite is known as fuller's earth, a term that can also refer to attapulgite, a mineralogically distinct clay mineral that exhibits similar properties.
Hills, cliffs, and slopes that contain fuller's earth can be unstable, since this material can be thixotropic
, when saturated by heavy rainfall.
kneaded fuller's earth and water into woollen cloth to absorb lanolin
, oils, and other greasy impurities as part of the cloth finishing process. Similarly, it has been used as an ingredient in powdered, "dry" shampoos. Fuller's earth was also sold in pharmacies until recently for compressing pills and cleaning hats and fabrics.
Important uses are in absorbents and filters
. Because of this, it is used (with activated charcoal) in the treatment of paraquat
overdose to prevent the progression to pulmonary fibrosis
. Fuller's earth is also used by military and civil emergency service personnel to decontaminate the clothing and equipment of soldiers and CBRN (Chemical Biological Radiological Nuclear) responders who have been contaminated with chemical agents.
Fuller's earth was a key ingredient in the special effects process developed to simulate the tornado in the 1939 film, The Wizard of Oz
.
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
or claylike earthy material used to decolorize, filter, and purify animal, mineral, and vegetable oils and greases.
Occurrence and composition
Fuller's earth usually has a high magnesium oxide
Magnesium oxide
Magnesium oxide , or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium . It has an empirical formula of and consists of a lattice of Mg2+ ions and O2– ions held together by ionic bonds...
content. In the United States, two varieties of fuller's earth are mined, mainly in the southeastern states. These comprise the minerals montmorillonite
Montmorillonite
Montmorillonite is a very soft phyllosilicate group of minerals that typically form in microscopic crystals, forming a clay. It is named after Montmorillon in France. Montmorillonite, a member of the smectite family, is a 2:1 clay, meaning that it has 2 tetrahedral sheets sandwiching a central...
or palygorskite
Palygorskite
Palygorskite or attapulgite is a magnesium aluminium phyllosilicate with formula 2Si4O10·4 which occurs in a type of clay soil common to the Southeastern United States. It is one of the types of fuller's earth.-Name:...
(attapulgite) or a mixture of the two; some of the other minerals that may be present in fuller's earth deposits are calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
, dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
, and quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
.
In England, fuller's earth occurs mainly in the Lower Greensand
Greensand
Greensand or Green sand is either a sand or sandstone, which has a greenish color. This term is specifically applied to shallow marine sediment, that contains noticeable quantities of rounded greenish grains. These grains are called glauconies and consist of a mixture of mixed-layer clay...
. It has also been mined in the Vale of White Horse
Vale of White Horse
The Vale of White Horse is a local government district of Oxfordshire in England. The main town is Abingdon, other places include Faringdon and Wantage. There are 68 parishes within the district...
, Oxfordshire
Oxfordshire
Oxfordshire is a county in the South East region of England, bordering on Warwickshire and Northamptonshire , Buckinghamshire , Berkshire , Wiltshire and Gloucestershire ....
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. The Combe Hay
Combe Hay
Combe Hay is a village and civil parish in the English county of Somerset. It falls within the Cotswolds Area of Outstanding Natural Beauty. The parish has a population of 149.-History:Combe Hay was known in the Domesday Book as Cumb...
Mine was a fuller's earth mine operating to the south of Bath, Somerset until 1979. Other sites south of Bath included Frome
Frome
Frome is a town and civil parish in northeast Somerset, England. Located at the eastern end of the Mendip Hills, the town is built on uneven high ground, and centres around the River Frome. The town is approximately south of Bath, east of the county town, Taunton and west of London. In the 2001...
, Lonsdale
Lonsdale
-People:*Angela Lonsdale*Bruce Lonsdale*Christopher Lonsdale*Corrine Lonsdale*David Lonsdale*Derrick Lonsdale*Earl of Lonsdale*Edmund Lonsdale*Frederick Lonsdale, English dramatist*Gordon Arnold Lonsdale*Gordon Lonsdale*Harvey Lonsdale Elmes...
, Englishcombe
Englishcombe
Englishcombe is a village and civil parish in Bath and North East Somerset just outside Bath, England. The parish, which also includes the hamlets of Inglesbatch, Nailwell and Wilmington, has a population of 332.-History:...
Tucking Mill
Tucking Mill
Tucking Mill is a small hamlet within the parish of Monkton Combe, Somerset, England. It lies on Midford Brook and was a key point on the now disused Somerset Coal Canal....
and Duncorn Hill
Duncorn Hill
Duncorn Hill is a rounded hill with a flat top by the Fosse Way, on the limestone plateau south of Bath in Somerset, England. It is 585 feet above sea level and is a landmark. Its name is from the Celtic din for fort and corn meaning horn-shaped....
. Although these sites had been used since Roman times William Smith
William Smith (geologist)
William 'Strata' Smith was an English geologist, credited with creating the first nationwide geological map. He is known as the "Father of English Geology" for collating the geological history of England and Wales into a single record, although recognition was very slow in coming...
developed new methods for the identification of deposits of Fuller's earth to the south of Bath. Other English sources include a mine near Redhill, Surrey
Redhill, Surrey
Redhill is a town in the borough of Reigate and Banstead, Surrey, England and is part of the London commuter belt. Redhill and the adjacent town of Reigate form a single urban area.-History:...
(worked until 2000), and Woburn, Bedfordshire
Woburn, Bedfordshire
Woburn is a small Saxon village and civil parish in Bedfordshire, England. It is situated about southeast of the centre of Milton Keynes, and about south of junction 13 of the M1 motorway and is a popular tourist attraction.-History:...
, where production ceased in 2004.
In some countries calcium bentonite is known as fuller's earth, a term that can also refer to attapulgite, a mineralogically distinct clay mineral that exhibits similar properties.
Hills, cliffs, and slopes that contain fuller's earth can be unstable, since this material can be thixotropic
Thixotropy
Thixotropy is the property of certain gels or fluids that are thick under normal conditions, but flow over time when shaken, agitated, or otherwise stressed...
, when saturated by heavy rainfall.
Uses
The name reflects the first use of the material. In past centuries, fullersFulling
Fulling or tucking or walking is a step in woolen clothmaking which involves the cleansing of cloth to eliminate oils, dirt, and other impurities, and making it thicker. The worker who does the job is a fuller, tucker, or walker...
kneaded fuller's earth and water into woollen cloth to absorb lanolin
Lanolin
Lanolin , also called Adeps Lanae, wool wax or wool grease, is a yellow waxy substance secreted by the sebaceous glands of wool-bearing animals. Most lanolin used by humans comes from domestic sheep...
, oils, and other greasy impurities as part of the cloth finishing process. Similarly, it has been used as an ingredient in powdered, "dry" shampoos. Fuller's earth was also sold in pharmacies until recently for compressing pills and cleaning hats and fabrics.
Important uses are in absorbents and filters
Filter (chemistry)
In chemistry and common usage, a filter is a device that is designed to physically block certain objects or substances while letting others through. Filters are often used to remove solid substances suspended in fluids, for example to remove air pollution, to make water drinkable, and to prepare...
. Because of this, it is used (with activated charcoal) in the treatment of paraquat
Paraquat
Paraquat is the trade name for N,N′-dimethyl-4,4′-bipyridinium dichloride, one of the most widely used herbicides in the world. Paraquat, a viologen, is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic to human beings and animals...
overdose to prevent the progression to pulmonary fibrosis
Pulmonary fibrosis
Pulmonary fibrosis is the formation or development of excess fibrous connective tissue in the lungs. It is also described as "scarring of the lung".-Symptoms:Symptoms of pulmonary fibrosis are mainly:...
. Fuller's earth is also used by military and civil emergency service personnel to decontaminate the clothing and equipment of soldiers and CBRN (Chemical Biological Radiological Nuclear) responders who have been contaminated with chemical agents.
Fuller's earth was a key ingredient in the special effects process developed to simulate the tornado in the 1939 film, The Wizard of Oz
The Wizard of Oz (1939 film)
The Wizard of Oz is a 1939 American musical fantasy film produced by Metro-Goldwyn-Mayer. It was directed primarily by Victor Fleming. Noel Langley, Florence Ryerson and Edgar Allan Woolf received credit for the screenplay, but there were uncredited contributions by others. The lyrics for the songs...
.
Further reading
- Brady, G.S., Clauser, H.R., & Vaccari, J.A. (2002). Materials handbook. (15th ed.) New York: McGraw-Hill.
- Hosterman, J.W. and S.H. Patterson. (1992). Bentonite and Fuller's earth resources of the United States [U.S. Geological Survey Professional Paper 1522]. Washington, D.C.: United States Government Printing Office.