Minerals and Ores

Attapulgite

Attapulgite is a term that is synonymous with the more commonly used palygorskite. While palygorskite is the formal name used in the mineral nomenclature, attapulgite is still recognized commercially in the many products made from it. Attapulgite’s structure is commonly called a “chain-layer” or “ribbon-layer” silicate due to its unique mineral structure that manifests ribbons of alumino-silicate layers to be joined at their edges. Unlike bentonite (or montmorillonite), attapulgite crystals are needle shaped (acicular) rather than flat or flake-like. The result is a mineralogical version of organized Swiss cheese where the voids in the structure can be filled with liquids of all types. This structure produces a magnesium aluminum silicate clay of very fine particle size, or a micro-sponge that is naturally designed to absorb liquids. Attapulgites disperse well and exhibit excellent thickening, suspending and gelling properties without flocculation problems.

Attapulgite is also known as Fullers Earth and is closely related to sepiolite minerals. It has been mined in Georgia and Florida since the 1930s. These deposits are known around the world for their light tan to white color, high sorption capability, and very strong particle integrity. Attapulgite is used mainly in oil and grease absorbents, pet litter, soil amendments, and as a component of drilling muds.

Bentonite

Bentonite is an industrial ore that is mined throughout the world. It is formed from the alteration of siliceous, glass-rich volcanic rocks such as tuffs and ash deposits. The major mineral in bentonite is montmorillonite, a hydrated sodium, calcium, magnesium, aluminum silicate. Bentonite is known as “swelling” or “plastic” clay that effectively sorbs and retains relatively high amounts of water.

Bentonite has been mined for centuries, but for over 75 years the most famous deposits have been mined commercially in the United States. There are two types of bentonite produced in the U.S.: “Wyoming” or “western” bentonites are mined from sodium bentonite deposits in Wyoming, South Dakota and Montana; “southern” bentonites are mined from calcium bentonite deposits in the Gulf Coast states of Mississippi and Alabama.

Bentonite possesses strong colloidal properties and its volume increases several times when it comes in contact with water. These unique swelling and adhesive properties make bentonite ideal for use in an extensive range of applications.

Bentonite is used as a binding agent in the production of iron ore pellets; as a flow control agent in paints, dyes and polishes; as the clumping agent in clumping cat litter; as a sealant and lubricant in oil and water-well drilling; and in various pharmaceutical and cosmetic products.

Montmorillonite

Montmorillonite is a layered silicate belonging to the smectite group of phyllosilicate minerals. It is formed primarily by the alteration of extrusive volcanic rocks such as volcanic ash falls and ash fall tuffs. Commonly these minerals are products of geological weathering or hydrothermal alteration of silicate minerals and silica phases in these igneous rocks.

Montmorillonite occurs naturally as a sequence of stacked layers 1.0 to 1.5 nanometers thick. These layers are the fundamental building blocks of montmorillonite and are strongly two-dimensional. These layers are frequently described as “stacks of cards” or “layers of cards” to better describe their unique structure and form. As a result of its unique structure, montmorillonite possesses the ability to absorb large amounts of water and other liquids. The liquid is sorbed onto, or hydrates, the layers at the interlayer cation site, causing swelling. The result is a mineral that can absorb in 2-10 times its weight of liquid.

It is the absorption and swelling characteristics that makes montmorillonite so useful in industrial and commercial applications. Montmorillonite is used in cat litters, industrial oil absorbents, filtration media, animal feeds, soil amendments and agricultural applications.