What is Attapulgite?
Attapulgite, a naturally occurring clay mineral having crystalline hydrated magnesium alumina-silicate with a three dimensional chain structure , alumina silicate having a theoretical formula of Mg5 Si8O20 (OH)2 (OH2)4.4H2O. The significant substitution Mg, Al, Fe ions at octahedral position and Ca,Na,K ions interlayer cation.
The montmorillonite associated with the attapulgite-bearing rocks of Digma Formation is of calcium base. It is non-swelling clay and predominantly classed as fullers earth, similar in this respect to attapulgite. World fuller’s earth, however, is generally comprising minerals such as attapulgite (palygorskite) or montmorillonite or a mixture of the two (grades from attapulgite-rich to montmorillonite-rich clays). The attapulgite-rich claystones of Digma Formation were proved to be of industrial value in term of oil wells drilling, decolorizing and absorbing characteristics (Al-Bassam, 1998). As so far mentioned, the attapulgite claystone contains other non-clay minerals (quartz, calcite, gypsum …etc), which were formed in situ or were transported into the deposit during its formation, and these may approach levels of 30 weight percent or more. This motivates the need to upgradethe attapulgite by effective method to enhance both clay performance and commercial value.