Illite properties

Initially, there are several types of micas which have similar properties but which have different physical and chemical origins. Illite, the low potassium aluminous mica-like mineral ( 10 X, non-expandable structure upon glycollation) can form diagenetically (Velde and Hower,... 

Intact soil cores (6.7 cm i.d.) were taken with spilt spoon at depths of 1 to 2 meters from a field test site located approximately 50 km east of Cincinnati, Ohio. The soil in this interval consists mainly of quartz (60%) and clay minerals (35%) with minor amounts of plagioclase and potassium feldspar. The majority of clay is illite and smectite, with minor amount of kaolinite. Soil chemical properties were analyzed prior to, and after, electroosmosis, in order to evaluate the effects of electroosmosis on the distribution of elements within the soil column. Sampled cores were wrapped in aluminum foil and stored at 12°C until the EO cell was assembled. 

Properties of Pillared Interstratified Illite/Montmorillonites and of Pillared Reference Montmorillonite... 

Of special significance with respect to their properties as sorbents are the clay minerals (e.g. kaolinite, montmorillonite, vermiculite, illite, chlorite), mainly due to their high exchange capacity. 

Diffusional transfers of potassium and silicon between sandstones and shales may be sufficient to accomplish feldspar dissolution, illitization, and quartz cementation (Thyne, 2001 Thyne et al, 2001). Losses of the magnitude observed for detrital carbonates in shales exceed the capacity of diffusion-mediated transfer. Large-scale advection seems required, although our understanding of shale permeabilities seems to preclude this (Bjprlykke, 1989, 1993 and Lynch, 1997). The possibility of convection driven by salinity heterogeneity within thick shale sequences has been demonstrated by Sharp et al (2001), who note that more information for rock properties and fluid compositions within deep basinal shales is needed before the generality of their results can be assessed. 

The third group of clay minerals of minor technological significance comprises the illite minerals. The structure and properties of clay minerals and clays are dealt with in detail, for instance, in the treatise by Grim (1962), by van Olphen (1977), in the textbook by Worall (1964, 1969), and elsewhere. 

Sorption in aquifers takes place mainly on clay minerals, organic matter and oxides, and is differently modeled depending on the properties of the solid. Clay minerals such as smectite and illite carry a charge due to... 

This value was assumed on the basis of the high CEC of the Brucedale clay soil (220 pcquiv/g), which indicates that the clay mixture in the soil has properties more like illite (a = 90-130 m2/g, CEC = 200-400 p,equiv/g) than like kaolinite (a = 10-20 m2/g, CEC = 20-60 xequiv/g). The ranges of clay properties are taken from Talibudeen (46). 

In a survey of U.S. stream sediments, Kennedy (1965) concluded that the makeup and properties of the stream sediments essentially equaled that of local soils. In the eastern states (50 to 150 cm precipitation), dominant clays in the <4 jum (0.004 mm) fraction were illite, kaolinite, ver-miculite, and interlayered clays, with a CEC of 14 to 28 meq/lOOg. In central and west-central states (25 to 100 cm precipitation) Kennedy found dominant smectite, vermiculite, mixed-layer illite, kaolinite, quartz, and feldspar in the <4 /zm fraction, with a CEC range of 25 to 65 meq/100 g. In California and Oregon, because of the wide range of wet and dry conditions (<25 to >200 cm precipitation), clays were highly variable, and had a range of CEC s from 18 to 65 meq/l(X) g for the <4 /um fraction. 

The second example concerns the surface heterogeneity of clay minerals. Important problems, such as limited yield of oil recovery arising during oil exploitation, involve interaction of pore filling fluids with the minerals that form the reservoir walls. The clay minerals, due to their relatively high specific surface area and electrical charge density, are the most active for the retention of oil. Illites and kaolinites are the clay minerals that are most frequently found and their wettability properties are believed to be in relation to the heavy oil ends retention process. 

Surface heterogeneity of such minerals influences certainly their ability to retain petroleum in the reservoir. Therefore, we have examined by IGC at finite concentration, the surface properties of illites and kaolinites having a known genesis heritage, transformation (degradation, agradation) or neoformation. 

---