Über die chemische verwitterung von tonmineralen (experimentelle untersuchungen)

Do clay mineral dissolution rates reach steady state?

“…2001 Clay mineral dissolution rates earlier findings (Heydemann, 1966;Holmqvist, 2001;Köhler et al, 2003). The BET surface area of most of the postexperiment powders corresponds closely to that of the original illite.…”

Experimental study of the effect of pH on the kinetics of montmorillonite dissolution at 25°C

“…Heydemann, 1966;Novak and Č ičel, 1978;Kline and Fogler, 1981a,b;Furrer et al, 1993;Zysset and Schindler, 1996;Bauer and Berger, 1998;Cama et al, 2000;Huertas et al, 2001;Tournassat et al, 2003;Nakayama et al, 2004;Amram and Ganor, 2005;Choi et al, 2005a,b;Metz et al, 2005a,b;Sánchez et al, 2006;Golubev et al, 2006) that have considered dissolution-affecting processes including: formation of surface complexes, evolution of reactive surface area, effects of solution saturation, and rate control by steady state vs. initial dissolution reaction(s). The results are in some cases discrepant as they were obtained under different experimental conditions (batch or flowthrough reactors, far or close to equilibrium conditions), using different smectites (in addition to raw or pretreated, 0016-7037/$ -see front matter Ó 2008 Elsevier Ltd. All rights reserved.…”

Stoichiometry of smectite dissolution reaction

“…There is an ongoing discussion on whether phyllosilicates such as mica, chlorite, talc, kaolinite and smectite dissolve congruently (e.g., Heydemann, 1966;Novak and Č ičel, 1978;Luca and MacLachlan, 1992;Furrer et al, 1993;Nagy, 1995;Gates et al, 1996;Komadel et al, 1996;Malmström and Banwart, 1997;Bauer and Berger, 1998;Schlabach et al, 1999;Sutheimer et al, 1999;Brandt et al, 2003;Kohler et al, 2003;Sato et al, 2003;Hoffmann et al, 2004). The dissolution rate of a phyllosilicate may be calculated independently based on the release of each of the different major elements that occupy its tetrahedral and octahedral sites.…”

“…Therefore, it can be used to calculate the chemical composition of the smectite itself from the composition of the raw bentonite sample. Furrer et al, (1993), Gates et al, (1996), Heydemann et al, (1966), Hofmann et al, (2004, Luca and MacLachlan, (1992), Novak and Cicel, (1978), Sato et al, (2003) and Schlabach, (2000) …”