Transformation of minerals of the montmorillonite family into 10 Å. micas

Abstract

IN his work on the mineralogy of soils colloids G. Nagelschmidt, 2 suggests the possibility of a reversible change of the type montmorillonite @ illite @ muscovite.We have attempted to establish experimentally the existence of this transformation following fixation or departure of the potassium from between the fundamental structural sheets of the mica type. The initial material was montmorillonite from Camp Bertaux, Morocco, separated from its impurities by sedimentation. As it was evident a priori that the alteration of montmorillonite into illite necessitates (1) saturation of the base-exchange capacity of the minerals by potas: slum, and (2) the departure of the layers of water from between the structural sheets of the montmorillonite, we finally, after several attempts, were led to make use of the following technique.The sample of montmorillonite was first of all saturated with potassium by treatment with a normal solution of KC1 ; then, after decantation of the excess of the solution, 200 c.c. of normal KOH solution were added per 4 grams clay. It was boiled 8 hours and, in order to avoid loss of material by projection, it was convenient to place the suspension in an Erlenmeyer flask attached to a vertical cooling column. The product was then filtered, washed, and dried for one hour in an oven. After this treatment the clay already showed a sandy consistency.

Dehydroxylation Kinetics of Clay Minerals and Its Application to Friction Heating Along an Imbricate Thrust in an Accretionary Prism

“…The measured TG curves for kaolinite show one stage of weight loss by dehydroxylation (Figure 5a), whereas the TG curves for chlorite demonstrate two stages of dehydroxylation (Figure 5b), consistent with previous studies by Brindley and Ali (1950), Caillère and Hénin (1957), Grim (1968), and Brindley and Chang (1974). The two stages of dehydroxylation occur within the brucite layer at lower temperatures (~500-600 °C) and the talc-like 2:1 layers at higher temperatures (~700-800 °C).…”

“…An exception is the study by Tsuzuki and Nagasawa (1957), who determined the kinetic parameters for the dehydroxylation reactions of chlorite and other hydrous minerals by isothermal heating experiments using a thermobalance. However, they did not take account of the fact that chlorite dehydroxylation occurs in two stages (Brindley & Ali, 1950;Brindley & Chang, 1974;Caillère & Hénin, 1957;Grim, 1968), which requires more systematic analyses for the accurate determination of the kinetic parameters of chlorite. Figure 2.…”

Spectral and mineralogical alteration process of naturally-heated CM and CY chondrites

“…(i) [HS-I to II] Hydrous minerals such as Fe-rich serpentines (cronstedtite decomposes at 470 °C; Caillère & Hènin, 1957) and tochilinite (decomposes at ~245 °C; Ivanova et al, 2005;Tonui et al, 2002) became amorphous and decomposed.…”

Geology and technology of the Grants uranium region

“…Study by Megrue (1962, Columbia Univ., Ph.D. thesis) indicated that true montmorillonite of the original Summerville has been altered to mixed layer montmorilloniteillite and illite-chlorite. Megrue suggested that the alteration of true montmorillonite to illite is indicative of temperatures above one hundred degrees centigrade, as based on the work of Caillere and Henin (1949) and Weaver (1958).…”