Corundum (sapphire) has a defined Mohs hardness of 9, while benitoite is much softer. He named it benitoite for its occurrence near the headwaters of the San Benito River in San Benito County, California.
Gray shale and bentonites ; Colorado Springs, Colorado Bentonite is an swelling consisting mostly of. It usually forms from weathering of in seawater, which converts the present in the ash to clay minerals. Bentonite beds are white or pale blue or green in fresh exposures, What does the Benitoite stand for?
to a cream color and then yellow, red, or brown as the exposure is weathered further. As a swelling clay, bentonite has the ability to absorb large quantities of water, which increases its volume by up to a factor of eight. This makes bentonite beds unsuitable for building and road construction. However, the swelling property is used to advantage in and groundwater sealants.
The montmorillonite making up bentonite is anwhich takes the form of microscopic platy grains. These give the clay a very large total surface area, making bentonite a valuable.
The plates also adhere to each other when wet. This gives the clay a cohesiveness that makes it useful as a and as an additive to improve the plasticity of clay used for. One of the first findings of bentonite was in the near. Thealong with others in stratigraphic succession, was named afterin the mid-19th What does the Benitoite stand for?
by and of the U. Bentonite has since been found in many other locations, including China and Greece. Total worldwide production of bentonite in 2018 was 20,400,000 metric tons. It forms by devitrification of volcanic ash ortypically in a marine environment. This results in a very soft, porous rock that may contain residual crystals of more resistant minerals, What does the Benitoite stand for?
which feels soapy or greasy to the touch.
What does benitoite mean?
However, in commerce, the term bentonite is used more generally to refer to any swelling clay composed mostly of clay minerals, which includes montmorillonite. This means that a crystal of montmorillonite consists of layers, each of which is made up of two T sheets bonded to either side of an O sheet. The T sheets are so called because each aluminium or silicon ion in the sheet is surrounded by four oxygen ions arranged as a tetrahedron. The O sheets are so called because each aluminium ion is surrounded by six oxygen or hydroxyl ions arranged as an octahedron.
Water molecules can easily infiltrate between sheets and fill the remaining sites. This accounts for the swelling property of montmorillonite and other smectite clay minerals. The different types of bentonite are each named after the respective dominant cation.
For industrial purposes, two main classes of bentonite are recognized: sodium and calcium bentonite. Sodium bentonite is the more valuable but calcium bentonite is more common.
In andcompletely weathered volcanic glass ash-fall beds are commonly referred to as K-bentonites when the dominant clay species is. Because of its excellent properties, it is often used in for and gas wells and boreholes for geotechnical and environmental investigations. The property of swelling also makes sodium bentonite useful as a sealant, since it provides a self-sealing, low permeability barrier. It is used to line the base offor example.
Bentonite is also part of the backfill material used at the. Various surface modifications to sodium bentonite improve some or sealing performance in geoenvironmental applications, for example, the addition of polymers. Sodium bentonite can be combined with as fertilizer. These permit slow oxidation of the sulfur toan important plant nutrient, and maintain sulfate levels in rainfall-leached soil longer than either pure powdered sulfur or.
It is the main active ingredient ofprobably one of the earliest industrial cleaning agents. Calcium bentonite may be converted to sodium bentonite termed sodium beneficiation or sodium activation to exhibit many of sodium bentonite's properties by an process.
As What does the Benitoite stand for? practiced, this means adding 5—10% of a soluble sodium salt such as to wet bentonite, mixing well, and allowing time for the ion exchange to take place and water to remove the exchanged calcium.
Some properties, such as viscosity and fluid loss of suspensions, of sodium-beneficiated calcium bentonite or sodium-activated bentonite may not be fully equivalent to those of natural sodium bentonite. For example, residual calcium carbonates formed if exchanged cations are insufficiently removed may result in inferior performance of the bentonite in geosynthetic liners.
Minor uses include filler, sealant, and catalyst in petroleum refining.
Calcium bentonite is sometimes marketed as fuller's earth, whose uses overlap with those of other forms of bentonite. Bentonite also curtails by its propensity for aiding in the formation of. Much of bentonite's usefulness in the drilling and industry comes from its unique properties. Relatively small quantities of bentonite suspended in water form a viscous, material.
Most often, bentonite suspensions are alsoalthough rare cases of behavior have also been reported. At high enough concentrations about 60 grams of bentonite per litre of suspensionbentonite suspensions begin to take on the characteristics of a a fluid with a minimum yield strength required to make it move. Bentonite is also used as a binding agent in the manufacture of iron ore pellets as used in the steelmaking industry. Bentonite, in small percentages, is used as an ingredient in commercial and homemade clay bodies and ceramic glazes.
It greatly increases the of clay bodies and decreases settling in glazes, making both easier to work with for most applications. The ionic surface of bentonite has a useful property in making a sticky coating on sand grains. When a small proportion of finely ground bentonite clay is added to hard sand and wetted, the clay binds the sand particles into a moldable aggregate known as used for making molds in.
Some river deltas naturally deposit just such a What does the Benitoite stand for? of clay silt and sand, creating a natural source of excellent molding sand that was critical to ancient metalworking technology. Modern chemical processes to modify the ionic surface of bentonite greatly intensify this stickiness, resulting in remarkably dough-like yet strong casting sand mixes that stand up to molten metal temperatures.
Beach sand consisting of only silica and shell grains does not mold well compared to grains coated with bentonite clay. This is why some beaches are much better for building sandcastles than others.
They are also used for clarifying wine, liquor, cider, beer, mead, and vinegar. Bentonite has the property of relatively large amounts of molecules from aqueous solutions. Consequently, bentonite is uniquely useful in the process ofwhere it is used to remove excessive amounts of from. Were it not for this use of bentonite, many or most white wines would precipitate undesirable clouds or hazes upon exposure to warm temperatures, as these proteins.
It also has What does the Benitoite stand for? incidental use of inducing more rapid of both red and white wines. Bentonite is also considered an effective low-cost adsorbent for the removal of ions from aqueous solutions contaminated What does the Benitoite stand for?.
It is also used to absorb oils and grease. It helps ensure that the active agent is uniformly dispersed and that pesticides and fertilizers are retained on the plants. It also acts as a stabilizer and extender in these products. It is used to line the base of to prevent migration offor quarantining metal pollutants of groundwater, and for the sealing of subsurface disposal systems for spent nuclear fuel. Similar uses include makingwaterproofing of below-grade walls, and forming other impermeable barriers, e.
This technique allows for more convenient transport and installation, and it greatly reduces the volume of bentonite required. It is also used to form a barrier around newly planted trees to constrain root growth so as to prevent damage to nearby pipes, footpaths, and other infrastructure. Farmers use bentonite to seal retention ponds and line canals. Granular bentonite is being studied for use in battlefield wound dressings.
Bentonite is also sold online and in retail outlets for a variety of indications. Bentoquatam is a bentonate-based topical medication intended to act as a shield against exposure What does the Benitoite stand for?the oil found in plants such as or.
Bentonite can also be used as a desiccant due to its adsorption properties. Bentonite desiccants have been successfully used to protect pharmaceutical, nutraceutical, and diagnostic products from moisture degradation and extend shelf life.
In fact, in the most What does the Benitoite stand for? package environments, bentonite desiccants offer a higher adsorption capacity than desiccants. Studies carried out by The and partners in 2002—2003 focused on the application of locally sourced bentonite clays to degraded soils in the region. These applications were carried out in structured field trials. Applying bentonite clays effectively improved yields of forage grown under rain-fed conditions. Production costs are higher, but due to more production and the quality of the food, clay farmers could afford to invest and grow more and better food, compared to nonclay-using farmers.
A trench that would collapse due to the hydraulic pressure in the surrounding soil does not collapse as the slurry balances the hydraulic pressure. Forms for concrete, and rebar, can be assembled in a slurry-filled trench, and then have concrete poured into the form. The liquid concrete being denser displaces the less-dense bentonite slurry and causes the latter to overflow from the trench. This displaced bentonite slurry is then channeled to a recycling unit from which it can subsequently be reused in a new trench elsewhere on the construction site.
In addition, because the colloid is relatively impervious to water, a slurry wall can prevent the seepage of groundwater, which is useful in preventing the further spread of groundwater that has been contaminated by toxic material such as industrial waste. A small amount of bentonite is often added to make a clay mixture more plastic.
This makes the clay more easily formed, by methods such as throwing on a and various hand-building techniques. Short clay, such as a mixture consisting only of andcan be formed only by a limited set of methods such as pressing and molding, that do not put the clay under tension.
However, bentonite typically contains minerals that affect the color of the mix, and its swelling absorbent properties can make such a mix prone to significant shrinkage and potential cracking as it dries. The bentonite is added to slow or prevent the settling of the glazes. It can also improve the consistency of application of glazes on porous ware.
Once a certain amount of glaze water has been absorbed by the biscuit the bentonite effectively clogs What does the Benitoite stand for? pores and resists the absorption of further water resulting in a more evenly thick coat. Total worldwide production was 24,400,000 metric tons of bentonite and 3,400,000 metric tons of fuller's earth. Most high-grade natural sodium bentonite is produced from the western United States in an area between the of and the of Wyoming, and the Tokat Resadiye region of Turkey.
In the United States, calcium bentonite is mined primarily in and. Other major locations producing calcium bentonite include New Zealand, Germany, Greece, Turkey, India, and China. New York: Oxford University Press. Glossary of geology Fourth ed. Alexandria, Viriginia: American Geological Institute. British Geological Survey, Nottingham, England. Soil Science Society of America Journal. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.
Developments in Soil Science 9. Journal of the Science of Food and Agriculture. Surface and interlayer reactions: bentonites as adsorbents. Proceedings of the 10th International Clay Conference, Adelaide, Australia. A History of calcium montmorillonite.
Journal of Geotechnical and Geoenvironmental Engineering. Advances in Colloid and Interface Science. Transactions of the Indian Ceramic Society. Journal of Materials Processing Technology.
Mineralogy and sealing properties of various bentonites and smectite-rich clay materials. Drugs: Drug Safety and Availability. Arid Land Research and Management. Improving Soil Fertility and Water Holding Capacity with Clay Application: The Impact of Soil Remediation Research in Northeast Thailand. Australian Journal of Soil Research. British Geological Survey, Nottingham, England.