Electrochemical Oxidation of Pyrite Slurries

Electrolysis at electrode potentials of 0.8V vs. SCE and above leads to dissolution of pyrite in the anode compartment, while pure hydrogen gas is observed to evolve in the cathode compartment. The pyrite electro‐oxidation was found to occur via an autocatalytic pathway. Cyclic voltammetry and other experiments indicate that iron dissolved in the electrolyte contributes significantly to the electrochemical reactivity of pyrite slurries. A reaction pathway for pyrite electro‐oxidation is proposed. The influence of temperature, slurry concentration, and particle size on the rates of reaction is investigated thoroughly. Thermodynamic analysis indicates that hydrogen generation from aqueous pyrite slurries at reaction temperatures of about 150°C should occur at significantly lower voltages than that required for conventional water electrolysis.