Abstract
Pyrite (FeS2) is a promising reducing agent that can be used to remove atmospheric oxygen in repositories for the geological disposal of high-level radioactive waste. In order to estimate the rate of pyrite oxidation in a repository environment, we conducted experiments using dissolved oxygen (DO) in alkaline solutions at 298 K. Pyrite samples were treated with alkaline solutions (pH adjusted to ∼ 9 and ∼ 10); these solutions were then saturated with air and adjusted to various ionic strengths (IS). The DO, total Fe, and SO42- concentrations in the experimental solutions were measured at regular intervals along with the pH. The rate constant for pyrite oxidation in solution was approximately 1/20 that determined in previous studies on pyrite oxidation in pyrite-containing compacted purified sodium bentonite.
