| Issue |
J. Phys. Colloques
Volume 48, Number C1, Mars 1987
VIIth Symposium on the Physics and Chemistry of Ice
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|---|---|---|
| Page(s) | C1-527 - C1-533 | |
| DOI | https://doi.org/10.1051/jphyscol:1987172 | |
J. Phys. Colloques 48 (1987) C1-527-C1-533
DOI: 10.1051/jphyscol:1987172
RECENT EXPERIMENTAL WORK ON SOLUTE REDISTRIBUTION AT THE ICE/WATER INTERFACE. IMPLICATIONS FOR ELECTRICAL PROPERTIES AND INTERFACE PROCESSES
G.W. GROSS, A. GUTJAHR et K. CAYLORNew Mexico Institute of Mining and Technology, Socorro, NM 87801, U.S.A.
Résumé
Nous avons étudié la ségrégation de NaF, HCl, NaCl, NH4F et AFGP à l'interphase eau/glace. Le coefficient de distribution de NaF diminue de 2 x 10-1 (à la concentration initiale de la solution mère de 10-6 mol/l) à 3 x 10-3 (à 10-2 mol/l). Par contre, celui des deux chlorures reste constant à 3 x 10-3 entre les concentrations initiales de 5 x 10-6 mol/l et 5 x 10-4 mol/l. À la concentration de 10-6 mol/l de la solution mère, le coefficient de distribution de NH4F est fortement dépendant du pH de la solution liquide. AFGP est le plus soluble des dopants connus de la glace. Le coefficient de distribution est voisin de l'unité. Si le liquide n'est pas agité, des traces d'AFGP dans la solution mère augmentent le coefficient de distribution de HCl à cause d'instabilités des champs de flux de la chaleur et du dopant.
Abstract
Redistribution of NaF, HCl, NaCl, NH4F, and AFGP at the ice/water interface have been investigated under near-equilibrium constrained growth conditions. The distribution coefficient of NaF-declined from 2 x 10-1 (at 10-6 N initial liquid concentration) to 3 x 10-3 (at 10-2 N). By contrast, the distribution coefficient of the two chlorides was 3 x 10-3 and invariant with initial liquid concentrations in the range 5 x 10-6 N to 5 x 10-4 N. At 10-6 N concentration of the mother solution, the distribution coefficient of NH4F was found to be strongly pH dependent. AFGP is the most highly soluble of known impurities in ice, with a distribution coefficient close to unity. In unstirred solutions, traces of AFGP in the mother solution caused an increase in the distribution coefficient of HCl due to instabilities in the flux fields of heat and solute.