Clay minerals swelling

Clay minerals are alumino silicates with layer structures. The basic constituent elements Si and Al are substituted by other elements by diadochy. Clay minerals swell in water and... 

Shroll RM, Smith DE (1999a) Molecular dynamics simulations in the grand canonical ensemble Formulation of a bias potential for umbrella sampling. J Chem Phys 110 8295-8302 Shroll RM, Smith DE (1999b) Molecular dynamics simulations in the grand canonical ensemble Application to clay mineral swelling. J Chem Phys 111 9025-9033 Smith DE, Haymet ADJ (1992) Strucmre and dynamics of water and aqueous solutions The role of flexibility. J Chem Phys 96 8450-8459... 

Shroll, R. M. Smith, D. E. (1999). Molecular Dynamics Simulations in the Grand Canonical Ensemble Application to Clay Mineral Swelling. The Journal of Chemical Physics, 111, 9025. 

Shroll, R.M., and D.E. Smith. 1999. Molecular dynamics simulations in the grand canonical ensemble Application to clay mineral swelling. J. Chem. Phys. 111 9025-9033. 

Some clay minerals may absorb some of the water contained in the drilling mud. This will cause the clays to swe//and eventually reduce the borehole size to the point where the drill pipe becomes stuck. Prevention mud additives which prevent clay swelling e.g. potassium salt. 

Calcium siHcate hydrate is not only variable ia composition, but is very poody crystallised, and is generally referred to as calcium siHcate hydrate gel or tobermorite gel because of the coUoidal sizes (<0.1 fiva) of the gel particles. The calcium siHcate hydrates ate layer minerals having many similarities to the limited swelling clay minerals found ia nature. The layers are bonded together by excess lime and iatedayer water to form iadividual gel particles only 2—3 layers thick. Surface forces, and excess lime on the particle surfaces, tend to bond these particles together iato aggregations or stacks of the iadividual particles to form the porous gel stmcture. 

Osmotic swelling is a second type of swelling. Where the concentration of cations between unit layers in a clay mineral is higher than the cation concentration in the surrounding water, water is osmotically drawn between the unit layers and the c-spacing is increased. Osmotic swelling results in larger overall volume increases than surface hydration. However, only certain clays, like sodium montmorillonite, swell in this manner. 

The reactivity of steam can be reduced via pH control. The injection or addition of a buffer such as ammonium chloride inhibits the dissolution of certain mineral groups, controls the migration of fines, inhibits the swelling of clays, controls chemical reactions in which new clay minerals are formed, and... 

Bentonite is the name for a hydrous aluminum silicate comprised principally of the clay mineral montmorillonite, notable for its ability to swell in water and to form a very low-permeability seal." It is available as powder, granule (chip), or pellets. Powder and granule sizes are produced by processing after mining. Bentonite powder... 

Solutions of TKPP have been shown to have unique and advantageous properties for use in formulating a wide variety of well fluids. Its reasonable cost, worldwide availability, and nontoxic properties make it a preferred additive for use in many petroleum applications. It has been shown to be a most effective salt with respect to inhibiting hydration and swelling of clay minerals commonly encountered in drilling operations and/or reservoirs. Avoiding clay problems is the major impetus for the incorporation of potassium ions in well fluids, and the use of TKPP provides advantages over and above those available from other potassium salts. 

Pedoturbation is the constant internal turnover of soil material. Vertisols are churning heavy clay soils with a high proportion of swelling 2 1 clay minerals (FAO, 2001). These soils form deep wide cracks from the surface downward when they are desiccated, which happens at least once in each year. 

Clay minerals or phyllosilicates are lamellar natural and synthetic materials with high surface area, cation exchange and swelling properties, exfoliation ability, variable surface charge density and hydrophobic/hydrophilic character [85], They are good host structures for intercalation or adsorption of organic molecules and macromolecules, particularly proteins. On the basis of the natural adsorption of proteins by clay minerals and various clay complexes that occurs in soils, many authors have investigated the use of clay and clay-derived materials as matrices for the immobilization of enzymes, either for environmental chemistry purpose or in the chemical and material industries. 

Carrizosa MJ, Hermosin MC, Koskinen WC, Cornejo J (2004) Interactions of two sulfonylurea herbicides with organoclays. Clays Clay Miner 52 643-649 Celis R, Hermosin MC, Cornejo J (2000) Heavy metal adsorption by functionalized clays. Environ Sci Technol 34 4593-4599 Chappell MA, Laird DA, Thompson ML, Li H, Teppen BJ, Johnston CT, Boyd SA (2005) Influence of smectite hydration and swelling on atrazine sorption behavior. Environ. Sci Technol 39 3150-3156 Chiou CT (1989) Theoretical considerations of the partition uptake of nonionic organic compounds by soil organic matter. In Sawhney BL, Brown K (eds) Reactions and movement of organic chemicals in soils. Soil Science Society of America, Madison, WI, pp 1-29... 

The chemistry of an important group of naturally occurring materials is characterized by surface reactions many clay minerals possess what can be considered surface at its extreme. All clay minerals capable of intracrystalline swelling with separation of the silicate layers are—to overstate it—surface with a silicate layer on each side. Many principles and techniques of surface chemistry were first found with clay minerals. Nevertheless, the clay minerals will not be considered in this article, except for some comparison and analogies with surface compounds. 

The CEC of clay minerals is partly the result of adsorption in the interlayer space between repeating layer units. This effect is greatest in the three-layer clays. In the case of montmorillonite, the interlayer space can expand to accommodate a variety of cations and water. This causes montmorillonite to have a very high CEC and to swell when wetted. This process is reversible the removal of the water molecules causes these clays to contract. In illite, some exchangeable potassium is present in the interlayer space. Because the interlayer potassium ions are rather tightly held, the CEC of this illite is similar to that of kaolinite, which has no interlayer space. Chlorite s CEC is similar to that of kaolinite and illite because the brucite layer restricts adsorption between the three-layer sandwiches. 

The properties of both organic matter and clay minerals may affect the release of contaminants from adsorbed surfaces. Zhang et al. (1990) report that desorption (in aqueous solution) of acetonitrille solvent from homoionic montmorillonite clays is reversible, and hysteresis appears to exist except for K+-montmorillonite. This behavior suggests that desorption may be affected by the fundamental difference in the swelling of the various homoionic montmorillonites, when acetonitrile is present in the water solution. During adsorption, it was observed that the presence of acetonitrile affects the swelling of different homoionic clays. At a concentration of 0.5 M acetonitrile in solution, the layers of K+-montmorillonite do not expand as they would in pure water, while the layers of Ca +- and Mg +-montmorillonite expand beyond a partially collapsed state. The behaviors of K+-, Ca +-, and Mg +-montmorillonite are different from the behavior of the these clays in pure water. Na+-montmorillonite is not affected by acetonitrile presence in an aqueous solution. 

Lim CH, Jackson ML, Koons RD, Helmke PA (1980) Kaolins Sources of differences in cation exchange capacity and cesium retention. Qays Clay Miner 28 223-229 Low PE (1981) The swelling of clay III Dissociation of exchangeable cation. Soil Sci Soc Amer J 45 1074-1078... 

Many clay minerals have aluminosilicate layer structures. For example, in kaolinite, Al2(0H)4[Si205] (Fig. 7.5), the Al3+ are all in octahedral locations. Clay minerals of the smectite or swelling type, such as montmo-rillonite, can absorb large amounts of water between the aluminosilicate... 

FOSTER (M.D.), 1953. Geochemical studies of clay minerals 11 Relation between substitution and swelling in montmorillonite. Amer. Min. 38, 994-1006. 

MARTIN VIVALDI (J.L.) and MACEWAN (D.M.C.), 1960. Corrensite and swelling chlorite. Clay Miner. Bull., 4, 173-81. 

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