Industrial uses of clays have many applications such as coating and filler pigment for paper, filler for paint, rubber and plastics, formulation additives in food, insecticides, cosmetics, pharmaceutics, fertilizers and soil correctors, and also as a major component in ceramics .
Kaolin, also known as china clay, is a natural clay formed by chemical weathering of aluminium silicate minerals like felspars through a complex sequence of events. It is relatively pure clay predominantly consisting of kaolinite (Al2 Si2O5(OH)4),associated with other clay minerals like dickite, halloysite, nacrite and anauxite.
China clay resources in the country as per UNFC system as on 1.4.2010 have been placed at 2,705.21 million tonnes. The reserves constitute only about 7% of the resources at 177.16 million tonnes. Out of the total reserves, 70% (about 124 million tonnes) reserves are under proved category whereas 30% (about 53 million tonnes) reserves fall under probable category. The resources are spread over in a number of states of which Kerala holds about 25%, followed by West Bengal and Rajasthan (16% each) and Odisha and Karnataka (10% each). (Source: IBM)
Bentonite is essentially a highly plastic clay containing not less than 85% clay mineral, montmorillonite. Sodium bentonite is usually referred to as bentonite, whereas calcium bentonite is called fuller’s earth. Bhavnagar and Kachchh districts of Gujarat and Barmer district of Rajasthan are the major producing areas of bentonite. The sodium bentonite
mined in Rajasthan tends to be of lower quality and is used as foundry sand. Both activated and granular bentonite are produced in the country. Bentonite is exported both as unprocessed (crude) and processed (including activated) forms.
The total reserves/resources of bentonite in the country as per NMI data based on UNFC system as on 14.2015 have been estimated at 583 million tonnes out of which 15 million tonnes are categorised as Reserves. The bulk of the resources, i.e. 428 million tonnes (73%) are in Rajasthan, 144 million tonnes (25%) in Gujarat and the remaining in Tamil Nadu, Jharkhand and Jammu & Kashmir. Substantial quantity of 501 million tonnes (86%) of the total resources are placed under Unclassified and Not-known categories while 60 million tonnes (10%) under Foundry grade and 19 million tonnes (3%) under Poor/Blendable grades. About 3 million tonnes resources are placed under Drilling Fluid grade. (Source: IBM)