Swelling minerals

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. 

Alkylamines and diamines are generally classified as corrosive to the skin based on results from laboratory animal (rabbit) studies performed in accordance with the Department of Transportation (DOT) test method (84) rabbits are considered to be especially sensitive to alkylamines which even at low concentrations can induce skin redness and swelling. Oleylamine has been shown to induce mild to moderate skin irritation in laboratory rats when appHed at a concentration of 0.3% in mineral oil (Chemical Manufacturer s Association, 1985). Fatty amines which contain alkyl chains of 10—14 carbons are considered more irritating than related products which contain alkyl chains of 14—18 carbon atoms. Ethoxylation generally decreases the irritation potential of alkylamines. 

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. 

In appearance and on handling the material is somewhat intermediate between a wax and a rubber. It is also semi-tacky. Like isotactic polypropylene it is attacked by oxygen but unlike the isotactic material it swells extensively in aliphatic and aromatic hydrocarbons at room temperature. It is also compatible with mineral fillers, bitumens and many resins. 

Nitrile rubbers, copolymers of butadiene and acrylonitrile, are used for resistance to swelling by mineral oils and fuels enhanced by formulations with a high acrylonitrile/butadiene ratio. They have poor resilience and low-temperature properties. However, these rubbers should not be used with ketones, phenols or aromatic hydrocarbons [66-69]. 

Of particular importance for the application are the effects of the external compression and the ionic composition of the outer solution on the swelling degree. The reason is that hydrogels usually exist in mineralized aqueous solutions (soil solution) and are affected by compression, for example, produced by the surrounding particles of the soil. Even in the absence of any external load the compression develops due to the gel swelling in a constrained volume. 

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