Expandable Phyllosilicate Reactions with Lithium on Heating

Abstract

Abstract--A method using Li saturation and heating to 250~ to differentiate montmorillonite from beidellite and nontronite has been developed. The test utilizes three washings with 3 M LiCl and two washings with 0.01 M LiC1 in 90% methanol to prevent dispersion. An 'infinitely thick' sample (6-8 mg/ cm z) on a glass slide is used to avoid the effects of the reaction of a thin clay film with sodium of the slide when it is heated at 2500C. Solvation with glycerol rather than ethylene glycol is used, because all of the Li smectites studied expanded to some extent in ethylene glycol after the heating. The smectites included several montmorillonites, a nontronite, and saponites. The presence of interstratified montmorillonite and beidellite layers was clearly shown by the test for several smectite samples, including the so-called beidellites from Beidell, Colorado, and Chen-yuan, Taiwan, and several soil clays. The test thereby provides more mineralogical information than the often-used arbitrary dividing point between montmorillonite and beidellite at 50% tetrahedral charge. Heating the Li-saturated clays at 250*C caused substitution of 35 to 125 meq/100 g of nonexchangeable Li. These amounts exceeded the changes in cation-exchange capacity plus Li by 4 to 21 meq/100 g, except for the end-member beidellite from the Black Jack mine, Idaho. Fusion with LiNO3 at 300~ could not be used to differentiate between smectites instead of washin~ with LiC1 solution and heating to 250~ because fused montmorillonite subsequently expanded to 18 A with glycerol. Large increases in nonexchangeable Li were caused by the fusion of smectites, a vermiculite, and two partially expanded micas.

The Effect of Heat Treatments on the Total Charge and Exchangeable Cations of Ca-, Na-, and Li-Saturated Kaolinite

“…These data suggest that a portion of the Li ions was fixed within the kaolinite structure. A similar phenomenon, the migration of Li ions into the structure, has been observed for montmorillonite (Brindley and Ertem, 1971;Calvet and Prost, 1971;Greene-Kelly, 1953;Hofmann and Klemen, 1950;Jaynes and Bigham, 1987;Lim and Jackson, 1986;Sposito et al, 1983). It has been referred to as the Hofmann-Klemen effect (Glaeser and Meting, 1971).…”

Caracterização de neossolos regolíticos da região semiárida do Estado de Pernambuco

“…em ambos os casos de saturação, as amostras foram analisadas sob a forma de agregados orientados sobre lâminas de vidro. além dos tratamentos supracitados, as amostras que apresentaram minerais esmectíticos foram submetidas ao teste de greene-Kelly, cujo procedimento detalhado encontra-se em lim & Jackson (1986 as análises por drX foram realizadas sob tensão de 40 kV e corrente de 20 ma, radiação de Cu-Kα com monocromador de grafite acoplado, sob passo contínuo e varredura entre 3 e 70º 2θ para silte e argila natural. os agregados de argila montados sobre lâminas foram analisados no intervalo de 3 a 35º 2θ, exceto as lâminas sob solvatação com glicerol, as quais foram irradiadas no intervalo de 3 a 15º 2θ.…”

Late Quaternary clay mineral record in Central Lake Baikal (Academician Ridge, Siberia)

“…In addition, Li saturation and some K saturation were done on the less than 2-µm fraction in order to help identify the chemical composition and the genetic conditions of smectites, and to improve the quantification of chlorite, illite chlorite and illite-smectite mixed layers. For Li saturation (modified from Lim and Jackson, 1986), the clay suspension was washed with 2 N aqueous LiCl overnight. Samples were then rinsed with demineralized water, and prepared as oriented aggregates.…”