Bentonite is a clay rock, also known as montmorillonite clay, it usually contains small amounts of illite, kaolin, halloysite, chlorite, zeolite, quartz, feldspar, calcite and the like. Hardness 1-2, density 2~3g/cm3 The exchangeable cations of the smectite type, the content and size of the layer, bentonite can be divided into sodium bentonite (alkaline soil), calcium bentonite (alkaline soil), natural bleaching soil (soil acidity or acid clay), which contains calcium in bentonite. Calcium and sodium and calcium and magnesium group