Bentonite may have played a major role in Fuller’s earth formation.ByDr. Nitish Priyadarshi
Fig. Mining of Fuller's earth.
Fig. Fuller's earth.
Fig. Mining area.
Fig. Bentonite. Abstract:
Pakur is located in the north east corner of Jharkhand State of India. Major part of the district is characterized by undulating topography covered by basaltic flows of Rajmahal Trap. Fuller’s earth mining is limited up to a shallow depth only and it is done manually. Most of the Fuller’s earth is send to local market of Pakur and neighboring state of West Bengal. Local villagers have the ownership of the mining and the profit is distributed among them. Fuller’s earth is mainly of sedimentary origin. It occurs interstratified with geologically late sands and clays. It is thought that most fuller’s earth originated from volcanic ash. Montmorillonite and attapulgite are the principal constituents, and montmorillonite is characteristic of bentonite. There is further suggestion that it was derived from bentonite by natural leaching in surface water, assisted perhaps by plant acids and bacteria.
Discussion:
Pakur is located in the north east corner of Jharkhand State: at 23°40' to 25°18' latitude and 86°25' to 87°57' E. longitude. Pakur is bordered by Sahibganj district in North, Dumka district in South, Godda district in West and Murshidabad and Birbhum districts (of the West Bengal) in the East. Pakur has an area of about 696 square kilometres and a population of 899,200 (2011 Census). Pakur, famous for stone and Beedi (Biri) making industry, is one of the important revenue-earning districts of newly created Jharkhand State. Its black stone chips have got Asiatic fame in constructional qualities.Pakur was earlier a Sub-Division of Santhal Parganas district of Jharkhand.
Major part of the district is characterized by undulating topography covered by basaltic flows of Rajmahal Trap. The main geomorphological features of the district are the rolling peneplain in the south with numerous remnants of ancient ridges and resistant lava plateau of Rajmahal. These plateaus rise above the general level and occupy major part of the district. The general elevation of the hills and plateau varies from 70 to 371 m above MSL.
Rajmahal Trap is the major rock type in the district. The other geological formations of the district are alluvium, laterite and gondwana. In the eastern part of the district, recent alluvium occurs in patches, which is mainly composed of sand and sub ordinate clay. Laterites are mainly of in situ origin and have been formed by sub-aerial erosion of underlying basalts under favorable climatic conditions. Laterites provide a productive ground water reservoir due to their very porous and permeable nature. The most significant Barakar coal measures of Gondwana formation occurs in western part of the district.
The district of Santhal Paraganas is mainly a dissected upland of ancient crystalline rocks which are covered with thick flows of volcanic lava. The ancient crystalline rocks, collectively called the Archaean gneisses, cover the greater part of the district. The principal rock is a granitoid gneiss earlier known as the Bengal gneiss.
Fuller’s earth ( commonly known as Multani soil) mining is limited up to a shallow depth only and it is done manually. Most of the Fuller’s earth is send to local market of Pakur and neighboring state of West Bengal. Local villagers have the ownership of the mining and the profit is distributed among them.
Fuller’s earth is a variety of clay, so named because it has been used by fullers to full, or remove grease from cloth. Its marked absorptive powers, however, have caused it to be more widely used to filter and decolor oils, fats, and greases.
The dominant use (about 70 percent) of fuller’s earth is in petroleum refining for filtering and clarifying petroleum products, mainly lubricants, and about 10 percent is utilized in the refining of vegetable oils and animal fats. Its use is growing in domestic water purification. It also removes putrescence, odors, and even coliform bacteria from oily waste waters.
In oil refining, colored oils passed through fuller’s earth come out colorless. In addition, it removes naphtha gum, and improves the sludge and carbon content, acidity, and viscosity of lubricating oils. It removes color, odor, and taste from vegetable and animal oils. Fuller’s earth cannot be reused after filtering vegetable oils.
Minor uses include printing, abrasives, detection of coloring agents in food products, filler, and cosmetics. Fuller’s earth is a clay substance that is hugely popular for its healing property against acne and blemishes. It is very rich in magnesium chloride which helps to reduce acne. In oil refining fuller’s earth is being displaced by activated bentonite.
Fuller’s earth is mainly of sedimentary origin. It occurs interstratified with geologically late sands and clays. It is thought that most fuller’s earth originated from volcanic ash. Montmorillonite and attapulgite are the principal constituents, and montmorillonite is characteristic of bentonite. There is further suggestion that it was derived from bentonite by natural leaching in surface water, assisted perhaps by plant acids and bacteria. Ash deposited in situ becomes bentonite; that which is gradually washed in, with leaching of grain surfaces, become fullers earth. Extended weathering of fuller’s earth may yield Kaolin.
Reference:
Bateman, A.M. 1955. Economic mineral deposit. John Wiley & Sons, Inc. New York.
http://cgwb.gov.in/District_Profile/Jharkhand/Pakur.pdf
