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The effect of CO2(aq), Al(aq) and temperature on feldspar dissolution [electronic resource].

Published:
Washington, D.C. : United States. Dept. of Energy, 2003.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description:
PDF-file: 6 pages; size: 0.2 Mbytes
Additional Creators:
Lawrence Berkeley National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary:
The authors measured labradorite (Ca{sub 0.6}Na{sub 0.4}Al{sub 1.6}Si{sub 2.4}O₈) dissolution rates using a mixed flow reactor from 30 to 130 C as a function of CO₂ (3 x 10⁻³ and 0.6 M), and aluminum (10⁻⁶ to 10⁻³M) at pH 3.2. Over these conditions, labradorite dissolution can be described with a single rate expression that accounts for observed increases in dissolution rate with temperature and decreases in dissolution rate with dissolved aluminum: Rate{sub Si} (mol Labradorite cm⁻² s⁻¹) = k″ x 10{sup -Ea/2.303RT} [(a{sub H⁺}{sup 3n}/a{sub Al{sup 3+}}ⁿ)K{sub T}/(1+K{sub T} (a{sub H⁺}{sup 3n}/a{sub Al{sup 3+}}ⁿ))] where the apparent dissolution rate constant, k″ = 10{sup -5.69} (mol Labradorite cm⁻²s⁻¹); the net activation energy, E{sub a} = 10.06 (kcal mol⁻¹); H⁺-Al{sup 3+} exchange coefficient, n = 0.31; and silica rich surface complex formation constant K{sub T} = 4.5 to 5.6 from 30 to 130 C. The effect of CO₂(aq) on mineral dissolution is accounted for by changes in solution pH. At temperatures below 60 C, labradorite dissolves incongruently with preferential dissolution of Na, Ca and Al over Si.
Report Numbers:
E 1.99:ucrl-jrnl-200556
ucrl-jrnl-200556
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Note:
Published through SciTech Connect.
10/14/2003.
"ucrl-jrnl-200556"
Chemical Geology, vol. 217, N/A, January 10, 2005, pp. 213-225 217 ISSN 0009-2541; CHGEAD FT
Knauss, K; Carroll, S.
Funding Information:
W-7405-ENG-48
View MARC record | catkey: 14378702