Fullers earth, Material : Earth Clay

a) Attapulgite is a naturally mined clay. It is a needle-like clay mineral composed of magnesium-aluminum silicate. Major deposits occur naturally in Georgia, USA. Attapulgite and sepiolite have similar structures and both can be used in salt-water mud to provide low-shear rate viscosity for lifting cuttings out of the annulus and for barite suspension. Attapulgite and sepiolite are sometimes called "salt gel." Attapulgite has no capability to control the filtration properties of the mud. For use as an oil-mud additive, the clay is coated with quaternary amine, which makes it oil-dispersible and provides gel structure but does not improve the filter cake, unlike organophilic bentonite clay.
b) Attapulgite is a kind of crystalloid hydrous magnesium-aluminum silicate mineral, having a special laminated chain structure in which there is a crystalline lattice displacement existed. Thus it makes the crystals contain uncertain quantities of Na+, Ca+, Fe3+ and Al, and present in the shape of needles, fibers or fibrous clusters. Attapulgite has very good colloidal properties such as: specific features in dispersion, high temperature endurance, salt and alkali resistance, and also high adsorbing and de-coloring capabilities. Furthermore, attapulgite has certain plastic and adhesive characters. Its ideal molecular formula is: Mg5Si8O20(HO)2(OH2)4•4H2O
c) The attapulgite structure is somewhat between laminated and chain structure. Attapulgite looks like soil, and compact blocks which are found in the sedimentary rocks and the weathering crust. Attapulgite are white, hoar, caesious or celadon, or with some dim mercerization in color. The clay of attapulgite is fine and a bit greasy smooth, light in weight, crispy, and the fractured surface is like shells or in irregular shapes. Attapulgite has strong ability to absorb water. When it is wet, attapulgite shows plastic and adhesive properties; and when it gets dry, attapulgite does not shrink much and does not show cracks. When it is soaked in water, attapulgite collapses. The suspending liquid does not create soliquids and precipitates, when meeting electrolytes.