Chapter 6 Bentonite Applications

This chapter discusses the bentonite applications. Bentonites are comprised predominantly of the smectite group of minerals. Calcium montmorillonite is the most predominate of the smectite minerals and is found in many areas of the world. Sodium montmorillonite is relatively rare in occurrence in comparison with calcium montmorillonite. Beidellite is the aluminum montmorillonite and is also relatively rare in occurrence. The smectite minerals occur as extremely fine particles of the order of 0.5 μm or less. Exchangeable cations such as sodium, calcium, and magnesium occur between the silicate layers, associated with water molecules. These elements are exchangeable and the property of exchange capacity is measured in terms of milliequivalents per 100 grams. The property of ion exchange and the exchange reaction are very important in many of the applications in which the smectite minerals are used.