Minimizing mass transfer effects in granular iron batch tests using GEM reactors

The glass encased magnet (GEM) batch reactor was designed to permit reactivity studies of granular iron with good mixing, and minimal abrasion. This study compared the GEM reactor with two conventional batch test designs (for granular iron studies). In the GEM reactor experiments, the reduction of 4-chloronitrobenzene with Connelly granular iron was found to proceed at about twice the maximum rate of the reaction mixed by orbital shaking or rolling, indicating that mass transfer was minimized in the GEM tests. In addition, the reproducibility of GEM tests was superior, possibly due to abrasion or other variations to the grain surfaces that occurred in the other types of tests. The biases and uncertainties in kinetic parameters estimated from the shaker and roller experiments were shown to be significant compared to the GEM derived parameters.