Natural Lake and Pond Building Services
Clay & Bentonite
Bentonite clay is formed by the alteration of minute glass particles derived from volcanic ash. It was named for Fort Benton, Mont., near which it was discovered.
Clay & Bentonite
When Bentonite comes into contact with water, it holds over ten times its dry weight. Additionally, as the bentonite clay swells, it forms a watertight barrier.
The formation of bentonite involves the alteration of volcanic glass to clay minerals; this requires hydration (taking up or combined with water) and a loss of alkalies, bases, and possibly silica, with the preservation of the textures of the original volcanic glass. 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.
Sodium bentonites absorb large quantities of water, swelling to many times their original volume, and give rise to permanent suspensions of gellike masses. These have been used to seal dams; in bonding foundry sands, asbestos, and mineral wool; as drilling muds; in portland cement and concrete, ceramics, emulsions, insecticides, soaps, pharmaceuticals, and paints; in the manufacture of paper; for clarifying water, juices, and liquors; and as a water softener to remove calcium from hard water. Calcium bentonites are nonswelling and break down to a finely granular aggregate that is widely used as an absorbent clay, sometimes called fuller’s earth.
Bentonite occurs in rocks that were deposited in the Ordovician to Neogene periods (about 488.3 to 2.6 million years ago). In the United States, the principal producers are Wyoming, Montana, California, Arizona, and Colorado. Important world producers are Greece, Japan, Italy, Brazil, Romania, Germany, Mexico, Argentina, Spain, India, Hungary, Poland, Canada, Turkey, and Cyprus.
Clay, soil particles the diameters of which are less than 0.005 millimetre; also a rock that is composed essentially of clay particles. Rock in this sense includes soils, ceramic clays, clay shales, mudstones, glacial clays (including great volumes of detrital and transported clays), and deep-sea clays (red clay, blue clay, and blue mud). These are all characterized by the presence of one or more clay minerals, together with varying amounts of organic and detrital materials, among which quartz is predominant. Clay materials are plastic when wet, and coherent when dry. Most clays are the result of weathering.