Introduction
Bentonite is a clay rock, also known as montmorillonite clay rock, normally containing a
small amount of illite, kaolin,
halloysite, chlorite, zeolite, quartz, feldspar, calcite and the like; hardness 1-2, density
2~ 3g / cm3. Exchangeable
cations of the smectite type, content and layer charge size, bentonite can be divided sodium
bentonite (alkaline
soil), calcium bentonite (alkaline soil), natural bleaching earth (soil acidity or acidic
clay), which calcium include
calcium bentonite and sodium and calcium and magnesium group.