Mica-montmorillonite

ML = Mixed layered mica-montmorillonite F = feldspar Q = quartz Bio = biotite Mo montmorillonite. 

Ca and Mg is inversed for vermiculite and montmorillonite (Levy and Shainberg, 1972). Further, the natural mica-beidellite interlayered minerals (rectorite) are sodi-calcic while the mica-montmorillonite minerals (allevardite) are sodi-potassic. Quite possibly, the site of charge imbalance changes the selectivity coefficients for exchangeable ions. The montmorillonite series of interlayering will produce illite and the beidel-litic series could lead to a paragonitic or possibly calcic mica. 

G = gibbsite, Kaol = kaolinite, Q = amorphous or crystalline SiO, Mi = potassic mica, Mo = K-beidellite, ML = mixed layered mica-montmorillonite minerals, F = potassium feldspar, Py = pyrophyllite. This is necessary to simplify portions of the diagrams where our knowledge of phase relations is not sufficient to judge the roles which each individual mineral will play. 

ML = mixed layered mica-montmorillonite All = allevardite-like phase ... 

Once the illite-chlorite zone is entered, i.e., the facies where dioctahedral mica-montmorillonite mineral solid-solutions are no longer stable, how does the assemblage change into muscovite-chlorite The major... 

HAMILTON (J.D.), 1967. Partially-ordered, mixed-layer mica-montmorillonite from Maitland, New South Wales. Clay Min. ], 63-78. 

Apparently winter lake waters are stable with respect to gibbsite relative to kaolinite, the micas, montmorillonite, and the feldspars whereas bottom sediments seem to be stable with respect to kaolinite. Kaolinite has been determined in bottom sediments of the Great Lakes as a major phase, but gibbsite has not been found so far. 

Recently, interest in clays as acidic catalysts has been quickened by the reported high catalytic activity of a synthetic mica-montmorillonite clay and its nickel-containing analogs. Wright et al. (247) have described the structure, thermal modification and surface acidity of the clay, which they designated SMM for synthetic mica-montmorillonite. 

NiSMM = Synthetic Mica Montmorillonite with Incorporated Nickel... 

Raffinate Hydrocracking with Palladium-Nickel— Containing Synthetic Mica-Montmorillonite Catalysts... 

Fe203, Ti02, MgO, and CaO are nearly always present in kaolinite samples and K20 and Na20 are usually present. Most samples either have excess Si02 or A1203-Mineral impurities such as quartz, anatase, rutile, pyrite, limonite, feldspar, mica, montmorillonite, and various iron and titanium oxides are commonly present in addition to a number of other minerals. Si and Al, in the form of hydroxides, apparently can occur as coatings on the kaolinite layers. Although many of these impurities are usually identified, seldom is the analysis sufficiently quantitative to determine if all the deviation from the ideal composition is due to these impurities. 

Z. Liu, D. Jiang, H. Cai, and E. Min, The Hydroisomerization Nature of Ni-substituted Mica Montmorillonite and its Silica Oligomers Pillared Clay in Hexane Reaction. Chem. J. Chin. Univ., 1991, 12, 397-399. 

From pyridine poisoning experiments and FT/IR measurements it can be concluded that this increased activity stems from the increased acidity of the resulting NiSMM (Ni-synthetic mica montmorillonite) clay, due to reduction of Ni. 

There has been renewed interest in catalytically active clays since the report by Swift and Black ( 1) to the effect that replacement of octahedrally coordinated aluminium ions by nickel or cobalt in synthetic smectite clays, as done by Granquist ( ), results in a new type of catalyst, called nickel- (or cobalt-) substituted mica montmorillonite (Ni(Co)SMM), which is very active in the isomerization and cracking of hydrocarbons. 

VAN SANTEN ET AL. Nickel-Substituted Mica Montmorillonite Clay... 

A typical reaction mixture used for the preparation of SMM consisted of 88 g SiO2/Al2O3 (25 % AI2O3), 67.2 g Al(isoprop)3, 9.1 g NH4F, and some water. About 120 g of white product was obtained after hydrothermal treatment (16 h at 300 C) and XRD confirmed that the product thus formed was pure synthetic beidellite. Since beidellite is NiSMM without Ni, it can also be described as synthetic mica montmorillonite (SMM). The composition of the clay was ... 

Figure 2. XRD of nickel-substituted mica montmorillonite (NiSMM) prepared according to the procedure detailed in ref. 2.

Rectorite is one of an almost infinite number of randomly mixed layer clays (411. collectively called illites, which include several other ordered interstratified varieties, including chlorite, corrensite and allevardite. Rectorite has the advantages of a mica and a smectite, in that alternate interlayers are expanding and non-expanding. It may be viewed as an ordered synthetic mica-montmorillonite (SMM) in the nomenclature familiar to catalytic... 

Other early MAS-NMR studies avoided the paramagnetic issue by synthesizing clays hydrothermally (16-18). Their conclusions were similar to previous conclusions Si is a powerful means of studying short-range order around Si in the lattice, while Al NMR is somewhat useful, but plagued by broadening and thus quantitation problems. Samples studied were synthetic beidellite (16], synthetic mica montmorillonites 117], and a series of synthetic 2 1 trioctahedral clays (18]. 

Mica Montmorillonite Nepheline syenite Strontium sulfate... 

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