Cation self-diffusion in chalcopyrite and pyrite

The self-diffusion coefficient of Fe⁵⁹ was measured in pyrite (FeS₂) and chalcopyrite (CuFeS₂) and found to exhibit an activation energy of 10.0 and 6.4 kcal/mole, respectively, in the temperature range of 100 to 300°C. The self-diffusion of Cu⁶⁴ and Ag^110m in chalcopyrite yielded activation energies of 12.1 and 17.5 kcal/mole in the same temperature range. The technique of nondestructive measurements is described, and diffusion mechanisms and implications for chemical leaching are discussed.