Parabolic dissolution kinetics of silicate minerals: An artifact of nonequilibrium precipitation processes?

Research Article| April 01, 1982 Parabolic dissolution kinetics of silicate minerals: An artifact of nonequilibrium precipitation processes? George R. Holdren, Jr.; George R. Holdren, Jr. 1Department of Geological Sciences, University of Rochester, Rochester, New York 14627 Search for other works by this author on: GSW Google Scholar John E. Adams John E. Adams 1Department of Geological Sciences, University of Rochester, Rochester, New York 14627 Search for other works by this author on: GSW Google Scholar Author and Article Information George R. Holdren, Jr. 1Department of Geological Sciences, University of Rochester, Rochester, New York 14627 John E. Adams 1Department of Geological Sciences, University of Rochester, Rochester, New York 14627 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1982) 10 (4): 186–190. https://doi.org/10.1130/0091-7613(1982)10<186:PDKOSM>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation George R. Holdren, John E. Adams; Parabolic dissolution kinetics of silicate minerals: An artifact of nonequilibrium precipitation processes?. Geology 1982;; 10 (4): 186–190. doi: https://doi.org/10.1130/0091-7613(1982)10<186:PDKOSM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The rate-limiting step for the dissolution of many primary silicate minerals is thought to be a surface-controlled reaction. This should result in dissolution rates that are linear functions of time. However, the observed dissolution rates for aluminosilicate minerals have commonly been characterized as "parabolic"—that is, the apparent rates of release of silicon and of the alkali ions are linear functions of the square root of time (t½). Here, data are presented which suggest that this discrepancy may result in part from the precipitation of secondary aluminosilicates during the dissolution experiments. In simulated dissolution studies, the kinetics of formation and the stoichiometries of precipitates can be studied unambiguously as functions of time, component concentrations, and pH. Results of these studies indicate that significant amounts of silicon are incorporated into amorphous aluminum-rich precipitates at dissolved silicon concentrations greater than 170 μm. At higher concentrations, silicon precipitation rates increase. These precipitation reactions result in apparent rates of addition of dissolved silicon to solution which are linear functions of t½. As a result of the type of precipitation reactions observed here, estimates for the rates of dissolution obtained for aluminum-rich silicate minerals may be low by as much as a factor of two. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.