What is the composition of bentonite?
What is the composition of bentonite?
Bentonite consists chiefly of crystalline clay minerals belonging to the smectite group, which are hydrous aluminum silicates containing iron and magnesium as well as either sodium or calcium. Two types of bentonite are recognized, and the uses of each depend on specific physical properties.
What type of mineral is bentonite?
Definition: Bentonite is defined as a naturally occurring material that is composed predominantly of the clay mineral smectite. Most bentonites are formed by the alteration of volcanic ash in marine environments and occur as layers sandwiched between other types of rocks.
Is bentonite a rock or mineral?
smectite minerals
Bentonite is a clay consisting mainly of smectite minerals, commonly formed by decomposition of volcanic ash or tuff, or sometimes from other igneous or sedimentary rocks. Bentonite is a very plastic clay that shrinks (or swells) markedly in response to the removal (or addition) of water.
How is bentonite clay mined?
Bentonite is surface mined through a process called back-casting where reclamation is performed by filling the mining pits with soils from subsequent pits while the mine is in production. Typically the topsoil layer is about 30 inches deep, which is removed using heavy equipment.
What are the types of bentonite?
Bentonites are classified into three main categories according to the proportion of exchangeable sodium and calcium cations they contain, their swelling index, and their pH. These categories are natural sodium bentonite, natural calcium bentonite, and activated calcium (sodium-calcium) bentonite.
What is the function of bentonite?
The main uses of bentonite are in drilling mud and as a binder, purifier, absorbent, and carrier for fertilizers or pesticides. As of around 1990, almost half of the US production of bentonite was used as drilling mud. Minor uses include filler, sealant, and catalyst in petroleum refining.
What is meant by bentonite?
Bentonite is a clay generated frequently from the alteration of volcanic ash, consisting predominantly of smectite minerals, usually montmorillonite. Other smectite group minerals include hectorite, saponite, beidelite and nontronite.
