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Bentonite
Bentonite ( ) is an Absorption (chemistry), absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-montmorillonite. Bentonite usually forms from the weathering of volcanic ash in seawater, or by hydrothermal circulation through the porosity of volcanic ash beds, which converts (devitrification) the volcanic glass (obsidian, rhyolite, dacite) present in the ash into clay minerals. In the mineral alteration process, a large fraction (up to 40–50 wt.%) of amorphous silica is dissolution (chemistry), dissolved and leaching (agriculture), leached away, leaving the bentonite deposit in place. Bentonite beds are white or pale blue or green (traces of redox, reduced ) in fresh exposures, turning to a cream color and then yellow, red, or brown (traces of oxidation, oxidized ) as the exposure is weathered further. As a swel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smectite
A smectite (; ; ) is a mineral mixture of various swelling sheet silicates (phyllosilicates), which have a three-layer 2:1 (TOT) structure and belong to the clay minerals. Smectites mainly consist of montmorillonite, but can often contain secondary minerals such as quartz and calcite. Terminology In clay mineralogy, smectite is synonym of montmorillonite (also the name of a pure clay mineral phase) to indicate a class of swelling clays. The term smectite is commonly used in Europe and in the UK while the term montmorillonite is preferred in North America, but both terms are equivalent and can be used interchangeably. For industrial and commercial applications, the term bentonite is mostly used in place of smectite or montmorillonite. Mineralogical structure The 2:1 layer (TOT) structure consists of two Silicon dioxide, silica (SiO2) Tetrahedral molecular geometry, tetrahedral (T) layers which are electrostatically cross-linked via an Al2O3 (gibbsite), or Fe2O3, Octahedral mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montmorillonite
Montmorillonite is a very soft phyllosilicate group of minerals that form when they precipitate from water solution as microscopic crystals, known as clay. It is named after Montmorillon in France. Montmorillonite, a member of the smectite group, is a 2:1 clay, meaning that it has two tetrahedral sheets of silica sandwiching a central octahedral sheet of alumina. The particles are plate-shaped with an average diameter around 1 μm and a thickness of 0.96 nm; magnification of about 25,000 times, using an electron microscope, is required to resolve individual clay particles. Members of this group include saponite, nontronite, beidellite, and hectorite. Montmorillonite is a subclass of smectite, a 2:1 phyllosilicate mineral characterized as having greater than 50% octahedral charge; its cation exchange capacity is due to isomorphous substitution of Mg for Al in the central alumina plane. The substitution of lower valence cations in such instances leaves the nearby oxygen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clays develop plasticity (physics), plasticity when wet but can be hardened through Pottery#Firing, firing. Clay is the longest-known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been radiocarbon dating, dated to around 14,000 BCE, and Clay tablet, clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtration, filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, often baked into brick, as an essenti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benstonite
Benstonite is a mineral with formula Ba6Ca6Mg(CO3)13. Discovered in 1954, the mineral was described in 1961 and named after Orlando J. Benston (1901–1966). Description and occurrence Benstonite is translucent and white, pale yellow, or pale yellow-brown in color. The mineral occurs as cleavable masses; cleavage fragments are nearly perfectly rhombohedral in shape. Cleavage faces are up to across and slightly curved. On large specimens, the faces exhibit a mosaic structure similar to that in some specimens of dolomite and siderite. Benstonite fluoresces red or yellow under x-rays and longwave and shortwave ultraviolet. The mineral also exhibits strong red phosphorescence. Benstonite is known to occur in Canada, China, India, Italy, Namibia, Russia, Sweden, and the United States. It occurs in association with alstonite, barite, barytocalcite, calcite, daqingshanite, fluorite, huntite, monazite, phlogopite, pyrite, sphalerite, strontianite, and quartz. Synthesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drilling Mud
In geotechnical engineering, drilling fluid, also known as drilling mud, is used to aid the drilling of boreholes into the earth. Used while drilling oil well, oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells. The two main categories of drilling fluids are water-based muds (WBs), which can be dispersed and non-dispersed, and non-aqueous muds, usually called oil-based muds (OBs). Along with their formatives, these are used along with appropriate polymer and clay additives for drilling various oil and gas formations. Gaseous drilling fluids, typically utilizing air or natural gas, sometimes with the addition of foaming agents, can be used when downhole conditions permit. The main functions of liquid drilling fluids are to exert hydrostatic pressure to prevent formation fluids from entering into the well bore, and carrying out drill cuttings as well as suspending the drill cuttings while d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
