ABSTRACT
Most iron released during the initial stages of pyrite oxidation ends up as iron hydroxide due to the relatively high pH on pyrite surfaces. It is commonly believed that pyrite oxidation can be controlled by adding alkaline material to pyrite, a widely used field practice. Wetland technologies are effective in treating the symptoms of pyrite oxidation when low levels of acidity are involved. More importantly however, "constructed wetlands" treat the symptoms of pyrite oxidation and not the problem itself which is pyrite oxidation. Novel microencapsulation (coating) technologies to prevent pyrite oxidation and acid production in pyritic wastes are currently under development in laboratory. During the leaching process, H2 O2 oxidizes pyrite and produces Fe3+ so that iron phosphate precipitates as a coating on pyrite surfaces. During the leaching process, process, H2 O2 oxidizes pyrite and produces an iron oxide coating on the surface of pyrite.
