Fuller's earth

Highley, D.E.. 1972 Fuller's earth. London, UK, HMSO, 31pp. (Mineral Dossier No. 3)

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Abstract/Summary

Fuller’s earth produced in the United Kingdom consists essentially of the clay mineral montmorillonite in which the principal exchangeable cation present is calcium. The mineral is highly adsorptive and absorptive, and possesses pronounced cation-exchange properties, which enable calcium montmorillonite (fuller’s earth) to be converted to sodium montmorillonite (bentonite) by a simple base-exchange process. Fuller’s earth has been workedin England since Roman times but until the 19th centuryw as used entirely by the woollen industry for ‘fulling’ or cleansing woollen cloth. Nowadays fuller’s earth and its sodium analogue bentonite have numerous industrial applications the more important of which are in glyceride oil refining, as a bonding agent in foundry moulding sands, as a suspension agent for oil well drilling muds and agricultural sprays, and for various civil engineering applications, as well as numerous other uses amongst which pharmaceutical preparations, such as face packs, are perhaps more popularly known. Commercially valuable fuller’s earth is confined, as far as is known, to the Jurassic and Cretaceous Systems, the mineral being worked by opencast methods from the Lower Greensand at Redhill in Surrey and Woburn in Bedfordshire and by drift mining from the Jurassic Upper Fuller’s Earth Clay near Bath in Somersetshire. Opencast workings are backfilled with overburden and the land is restored, as far as possible, to its former condition. Underground mining causes some subsidence but providing the surface is suitably treated agriculture is only temporarily affected. Known reserves of fuller’s earth are limited: the Lower Greensand is the most favourable horizon in which new deposits may be found. Fuller’s earth is processed by two different methods to give three main products; the natural earth, the sodium-exchanged earth and the acid-activated earth. Natural earth is processed by drying and grinding; the addition of small amounts of soda ash to the ground product yielding, in turn, the sodium exchanged earth. Acid-activated earth is produced by treating the raw clay with either sulphuric or hydrochloric acid to increase its active surface and hence its adsorptive properties. United Kingdom production of fuller’s earth was about 176,000 tonnes in 1970 of which about 40,000 tonnes was acid-activated. Exports of fuller’s earth and bentonite products were about 46,000 tonnes in 1970 and in the same year imports of bentonite (consisting principally of high grade Wyoming bentonite) were about 49,000 tonnes. There are two producers of fuller’s earth in the United Kingdom, Laporte Industries Limited and Berk Limited, a subsidiary of the Steetley Company Limited. In addition, a number of other companies import raw bentonite (chiefly Wyoming) in bulk for milling and bagging in this country.

Item Type:	Publication - Report
Programmes:	BGS Programmes > Economic Minerals
Funders/Sponsors:	Institute of Geological Sciences
Additional Keywords:	Mineral, Fuller's earth
NORA Subject Terms:	Earth Sciences
Date made live:	28 Jul 2025 15:36 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/539891

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