Quantifying Silica Reactivity in Subsurface Environments: An Integrated Experimental Study of Quartz and Amorphous Silica to Establish a Baseline for Glass Durability [report]

Patricia Dove
2003 unpublished
UNDERGRADUATES: Ms. Christina Lopano (now graduate student at Penn State) RESEARCH OBJECTIVE: An immediate EM science need is a reliable kinetic model that predicts long-term waste glass performance. A framework for which the kinetics of mineral-solution reactions can be used to interpret complex silicate glass properties is required to accurately describe the current and future behavior of glasses as synthetic monoliths or natural analogs. Reaction rates and mechanisms are essential elements
more » ... ssential elements in deciphering mineral/material reactivity trends within a compositional series or across a matrix of complex solution compositions. An essential place to start, and the goal of this research, is to quantify the reactivity of crystalline and amorphous SiO 2 phases in the complex fluids of natural systems. Perhaps the most important motivation for quantifying SiO 2 reactivity in the fluids of subsurface environments is that an understanding of fundamental controls on the reactivity of simple Si-O bonded phases establishes baseline behavior for silica phases widely found in waste storage environments. Host rock silicate minerals dominate virtually every repository rock-water system. Further, complex silicate glasses will be the front line of defense in containing radioactive wastes in both interim and long-term storage strategies. However, we have little quantitative understanding of pure SiO 2 reactivity in the solutes of natural and perturbed groundwaters even though current EM strategy calls for dispersal of waste into silica-based glass materials. Findings will establish quantitative relationships between silica reactivity and complex solution chemistries never investigated which are presently speculative at-best. Further, we will be able to uncover an
doi:10.2172/834685 fatcat:e5n5hsuidngtlgpk2vycmuj5by