Published online by Cambridge University Press: 15 February 1999
The behaviour of pyrite in the process of mechanical milling in air has been examined. Milled powders were characterized by scanning electron microscopy, Mössbauer spectroscopy working in transmission geometry and X-ray diffraction. In the presence ofoxygen, pyrite can readily be transformed to ferrous sulphate monohydrate, whichindicates that the Fe(II) goes from a low-spin state to to a high-spin state. Thetransformation mechanism is saturated after about 60 hours milling, but however it canbe markedly prolonged by further ageing at room temperature. The results also indicatethat mechanical milling is a useful room temperature process of material production.