Wyoming clay

French town (Montmorillon) where it was first discovered. In the USA, bentonite is principally mined in Wyoming - hence the term Wyoming clay . The type of bentonite, the source, and its purity influence its properties (Marchal et al. 1995). Bentonite is a complex hydrated aluminum silicate with exchangeable cationic components (Al, Fe, Mg) Si40io (0H)2 (Na+, Ca++). The most commonly used bentonite form in enology is the sodium bentonite. Sodium bentonite has enhanced protein binding capabilities over calcium bentonite. 

Fig. 8.4 Swelling property of bentonite O calculated using an MD simulation for beidellite, x experiments for Wyoming clay (Courtesy of Prof. K. Kawamura)...

Similar molecular weight poly(DMA-co-EPl), 1750 daltons, ca. 13 repeat units, and poly(TMDAB-co-DCB), 1500 daltons, ca. 11 repeat units were compared. The two condensation polymers appeared to be about equally effective in preventing the swelling of Wyoming bento-nite. Any small differences are probably due to repeat unit chemical structure differences rather than the small variations in polymer molecular weight. The presence of the hydroxyl group and the smaller N - N distance in poly(DMA-co-EPl) could affect polymer conforma-tion in solution, geometry of the polymer - clay complex, and surface properties of the polymer - clay complex as compared to poly(TMDAB-co-DCB). 

If mica-type sites are truly indicative of mica surfaces, and so on for montmoril Ionite etc., then of the clays examined, only the mica could be regarded as pure. The Montana vermiculite contained much montmoril Ionite, the Fithian illite contained mica and montmoril Ionite, the Wyoming bentonite contained some mica,... 

Clays. Two clays, SWy-a Na-montmorillonite (Crook County, Wyoming) and STx-1 Ca-montmorillonite (Gonzales County, Texas) were obtained from the Department of Geology, University of Missouri. Montmorillonite 27 (Bell Fourche, South Dakota) and montmorillonite 31 (Cameron, Arizona) were purchased from Ward s Natural Science Establishment. 

Cation Exchange Capacity. Various techniques have been used to measure the cation exchange capacity of the clay samples. Unless otherwise noted, in computation of equilibrium quotients, we shall use a value of 0.78 equivalents/kg clay, determined by a column method (14) on the calcium form of Wyoming montmoril-lonite at pH 5. 

Figure 10a. Adsorption of Ca(II) on the sodium form of Wyoming montmorillonite (Loading trace —1.4 X 10 mol Ca(ll)/kg, pH 5, equilibration for 18 hr.) Clay samples from Jacksons purification procedure ( ), NaCl + O.OIM NaOAc M, NaCl + O.IM NaOAc. Clay sarnies from Dowex column ( ), NaCl + O.IM NaOAc.

Ref P.P.Sharpe, "The Rifle in America, Funk Wagnails,NY(1947),38-40 Bentonite or Activated Clay. A broad term applied to material which has been derived from volcanic ash in which the mineral Montmorillonite predominates. Bentonite was first recognized in 1898 in Fort Benton(Wyoming) shales and has since been found in thick-bedded deposits over a wide area in Western US(Ref 1)... 

Knechtel and Patterson (1962) Clay spur bentonite bed. Crook Co., Wyoming analyst M.D. Foster. 

Kerr et al. (1950) Clay spur, Wyoming 5. Upton, Wyoming 6. Bell Fourchc, S.D. A portion of the octahedral Mg undoubtedly belongs in the interlayer position. 

---