Aluminum and magnesium-rich volcanic ash is defined as the killer 'bentonite' predominantly composed of montmorillonite, which is the result of chemical decomposition of tuffs and lavas. Bentonite is a versatile rock used in industry, agriculture, mining and engineering geology.
Ca, Na and Na-Ca montmorillonite, the geological characteristics of bentonite and their usage varies. Na bentonite with high swelling capacity and water swells 8-10 times its own volume, while the rate of swelling in Ca-bentonites is 2-3 times. Na and Ca-bentonites are used in works such as drilling and iron dust pelletization, and are used in works such as bleaching Ca-bentonites which have less swelling capacity and are commonly called 'bleaching earth-fuller earths'. By treating such killer with Na2CO3, swelling capacity can be increased as a result of Na / Ca ion substitution.