Bentonite

Bentonite, named after the Benton Formation, Fort Benton / Montana, is a rock that is a mixture of various clay minerals and most important component of montmorillonite ( 60-80%) contains, which explains its strong water absorption and swelling capacity. Other associated minerals are quartz, mica, feldspar, pyrite, or calcite. It is produced by weathering of volcanic ash.

Properties

The inner surface of a gram of 400-600 m2 (normal tone: 2 m2). It is therefore particularly valuable clay-humus complexes, so that the unloaded bentonite is also a good addition to the compost.

Water was stirred into the bentonite is a non- Newtonian fluid and has a thixotropic behavior: it behaves like a liquid when you shake it or stir it in a beaker, but is at rest, a fixed structure, so it u is a. , also well suited as a supporting liquid in the creation of diaphragm walls.

Occurrence

Bentonite, there is always where (not only) volcanic ash has been altered by hydrothermal activity and acids. One of the largest European populations located on the Greek island of Milos. There is bentonite, quartz and perlite ago in mineable quantities. Also related gold deposits have been found.

In Germany there are mineable deposits in Lower Bavaria ( Main Castle, Landshut and south of Landau an der Isar ) and in the eastern part of Upper Bavaria and in Thannhausen. These occurrences are in direct connection with the Ries event and were formed from impaktbedingten glasses. According to Unger, the bentonites in eastern Bavaria likely not by the Ries event, but by volcanism in the Pannonian Plain on aeolian shipping ( about 450 km distance) have been created, with both pre-and postriesische reserves are tapped.

Use

Bentonite is an important application in structural engineering, among others, Waterproofing and in dike construction. Due to their color, such seals are referred to as Brown tub. Bentonite is used as a lubricant in the driving of tunnels and pipes, Vibrating in narrow walls. In the recovery of heat from geothermal energy by the use of heat pumps, the collector pipes of the geothermal probes are often coated with bentonite, because it binds the water and prevents the formation of voids during freezing. In addition, bentonite has a meaning as a sealant in artificial ponds.

As supporting liquid in unsupported holes and slot walls

In the beverage industry ( in wine-making and in the manufacture of fruit juices ) as well as cocoa butter, it is as fining agents ( ie as sewage and precipitant ) used ( in the final product is no longer available). In food, it is added as a release agent. It is also known as a food additive under the designation E 558. Since May 31, 2013 E 558 is no longer permitted in the EU ..

The clay mineral montmorillonite is an important component in aquariums, garden ponds, especially for Koi. The mineral is dispersed in the form of special dried and ground clay powder in the pond. While the clay powder is distributed in the pond drops to the ground, it picks up heavy metals, toxins and other suspended particles and binds them. The clay mud can be sucked from time to time.

Bentonite, a natural clay mineral, is raw material of many cosmetics, as he takes a stabilizing effect in emulsions by its strong swelling and water absorption ability. The INCI name is bentonites.

In ceramics, bentonite (up to about 5%) used in small amounts as an additive to impart to the otherwise very lean masses ductile properties (" plasticity ").

Further applications are given by the use as adsorbents, which are:

• Oil and beverages
• Foundry Additives
• Paper Additives and Specialties
• Horticulture, to improve sandy soils
• Construction and civil engineering
• Detergent Additives
• Wastewater treatment
• Pharmaceuticals and Diagnostics / Electronics and Logistics
• Paints and coatings
• Plastic Additives
• Nanotechnology - surface coatings
• Litter
• Drying agents, for example, as a dry bag in packaging

In some of these applications of treated bentonite is used with quaternary ammonium compounds.

Furthermore, there are research approaches to use bentonite as an artificial barriers in the disposal of radioactive waste.

Bentonite as a mixture with different sands is distributed in construction technology under the trade name of bentonite as a building material and inscribed.