ABSTRACT
In order to understand the mechanisms of pyrite oxidation, one needs information on the molecular structure and frontier molecular electron orbital configuration of pyrite. Measurements of pyrite oxidation have a degree of uncertainty. The level of uncertainty decreases as the system variables are better understood. Several reaction progress variables (RPV) can be chosen to evaluate pyrite oxidation reactions. Each selected RPV has its own inherent strengths and weakness, depending on information sought and oxidation conditions used. Nicholson et al. investigating pyrite oxidation kinetics in a bicarbonate buffered system at pH values between 7.5 and 8.5 observed that the oxidation rate initially increased, reached a maximum at about 400 hours, and then decreased to a final relatively constant lower value. Hood observed that the rate of pyrite oxidation increased with increasing carbonate concentration. The pyrite oxidation model proposed by Moses and Herman was deduced from macroscopic pyrite oxidation data and no direct molecular evidence on most of the intermediates were presented.
