Smectites are overwhelming important clay minerals in soils. The expansive nature and negative charge of smectites cause them to be extremely reactive. Having high cation exchange capacity they influence adsorption and exchange reaction of K+, Ca2+, Mg2+, Na+, and many other cations essential for plant growth.

What is the use of smectite?

Significant volumes of Na smectites are used for various purposes in the manufacturing of many industrial, chemical and consumer products. Large quantities of Ca-M g smectites are used directly in iron foundries, in agricultural industries and for filtering and decolorizing various types of oils.

Why smectite is expanding clay?

Sodium cations are the most readily exchangeable and can promote adsorption of up to 32 layers of water molecules in smectite interlayers, causing clay volume expansion and flocculation. This expansion of the swelling clays will block pore throats and cause severe permeability reduction.