ABSTRACT
The need to prevent Acid Mine Drainage formation has triggered numerous investigations into the mechanisms of pyrite oxidation and its prevention. Pyrite oxidation can be significantly reduced by complexing FeIII, depriving the system of oxygen, and using alkaline material to neutralize any acid products. Pyrite oxidation models can be classified into two groups deterministic functional models, and mechanistic models. Pyrite used in the microencapsulation studies was separated from pyritic shale. When phosphate is introduced into the leaching-oxidation system, there are two possibilities. The first possibility is that the leaching oxidation solution is undersaturated with respect to FePO4 in the region adjacent to the surface of pyrite, but supersaturated with respect to FePO4 in the bulk solution. In the second possibility, the solution is supersaturated with respect to FePO4 in the region adjacent to the surface of pyrite and FePO4 will be deposited directly onto the surface of pyrite, forming a protective coating.
