Facts About Bentonite (Hydroclay)

Great Lakes Waterproofing uses a waterproofing version of Bentonite, here's some information about it's properties and uses.

SODIUM BENTONITE (Hydroclay)
Sodium bentonite expands when wet, it can absorb several times its dry mass in water. It is mostly used in drilling mud with drilling rigs for oil & gas wells and for geotechnical & environmental investigations. The property of swelling also makes sodium bentonite useful as a sealant, especially targeted for the sealing of subsurface disposal systems for spent nuclear fuel and for quarantining metal pollutants of groundwater. Similar uses include making slurry walls, waterproofing of below grade walls and forming other impermeable barriers (e.g. to plug old wells or as a liner in the base of landfills to prevent migration of leachate into the soil).

Early Americans found bentonite vital to their lives. Pioneers found moistened bentonite to be an ideal lubricant for squeaky wagon wheels. The mixture was also used as a sealant for log cabin roofing. The Indians found bentonite useful as a soap.

Small amounts of Wyoming bentonite were first commercially mined and developed in the Rock River area during the 1880s. Newer, more substantial deposits were discovered in other parts of Wyoming during the 1920s and the first processing plant in Wyoming was built during this period. Since that time many other processing plants have been built for the purpose of processing Wyoming sodium bentonite. Wyoming's Bentonite industry produced over 4.0 million tons of bentonite in 1999, with 644 mine and mill employees, and 240 contractor employees.
Wyoming bentonite is composed essentially of montmorillonite clay, also known as hydrous silicate of alumina. In more simplistic terms, the structure of bentonite is much like a sandwiched deck of cards. When placed in water, these cards or clay platelets shift apart. Bentonite attracts water to its negative face and magnetically holds the water in place. because of this unique characteristic, Wyoming bentonite is capable of absorbing 7 to 10 times its own weight in water, and swelling up to 18 times its dry volume.

POND LININGS
The usefulness of bentonite has been recognized for years for these types of applications. A range of bentonite products have been used for many years as permeability barriers in drainage ditches, livestock pond liners, amendments to pond dams, and even as municipal landfill liners in the form of geosynthetic clay liners. Many of the same bentonite properties that allow it to be used successfully in these applications can be readily extended to decorative water feature markets. In addition, bentonite is a natural geologic product and has a seventy year history of use in a wide array of industrial, environmental, and consumer products.

WELL DRILLING
Drilling mud, or drilling gel, is a major component in the well drilling process. Drilling mud is crucial in the extraction of drill cuttings during the drilling process. Bentonite, when mixed with water, forms a fluid (or slurry) that is pumped through the drill stem, and out through the drill bit. The bentonite extracts the drill cuttings from around the bit, which are then floated to the surface. The drilling mud, or gel, also serves to cool and lubricate the drill bit as well as seal the drill hole against seepage and to prevent wall cave-ins

TACONITE PELLETIZING
Taconite, a low grade iron ore, has been developed as an economic source for iron. During processing, the taconite is ground into a very fine powder. The ground taconite is then mixed with small amounts of bentonite which serves as a binder to the taconite. This mixture is processed into balls or pellets. The process is finished when these pellets are sintered in rotary kilns that give the pellets a hard surface. The taconite pellets are easy to handle at this point and can be loaded into various containers for shipment to steel mills.

METAL CASTING
Bentonite serves as an economical bonding material in the molding processes associated with the metal casting industry. Bentonite, when mixed with foundry molding sands, forms a pliable bond with the sand granules. Impressions are formed into the face of the bentonite/sand mixtures. Molten metal is pored into the impressions at temperatures exceeding 2,800 F. The unique bonding characteristics of bentonite insures the durability of the mold during these high temperatures. Once the process is complete, the bentonite/sand mold can then be broken away from the casting face and reused.

CAT LITTER
In recent years, bentonite has become a major component in the manufacturing of cat litter. Because of the unique water absorption, swelling, and odor controlling characteristics of bentonite, it is ideal for use in "clumping" types of cat litters. Clumping cat litter has become widely accepted as an economical alternative to conventional non-clumping type cat litters. Because bentonite forms clumps when wet, the clumps can easily be removed and disposed of. The remainder of the unused material stays intact and can continue to be used. clumping cat box litters will last longer with less frequency of changing.

ANIMAL/POUTRY FEEDS
For many years bentonite has been used as a binder in the feed pelletizing industry. Small amounts of bentonite can be added to feed products to insure tougher, more durable pellets. By absorbing excess moisture and oils, bentonite aids in the free movement of pellets, preventing lumping and caking. Research has been conducted which indicates that bentonite has additional benefits for both animals and poultry. The bentonite used in the feed slows the digestive system and enables the animal or fowl to better utilize the feed nutrients. Other studies have shown bentonite as a useful ingredient in the control of certain toxins which affect animals and fowl.

WINE MAKING
Have you ever wondered how your favorite white wine gets so clear and shiny? That brilliant sheen comes from removing large particles of protein and suspended solids that can cause a wine to go cloudy in the bottle, especially when the wine is exposed to heat. The winemaker actually adds bentonite to attract proteins and clarify the wine! The term used in winemaking is fining.

OTHER APPLICATIONS
Bentonite has also proved helpful in sealing freshwater ponds, irrigation ditches, reservoirs, sewage and industrial water lagoons, and in grouting permeable ground. In addition, it has been used in detergents, fungicides, sprays, cleansers, polishes, ceramic, paper, cosmetics and applications where its unique bonding, suspending or gellant properties are required