METASTABLE STRUCTURAL-MAGNETIC TRANSFORMATIONS IN SULFIDES IN COURSE OF OXIDATION

The modelling of the oxidation process of pyrite (FeS2) has been perfo rmed to explain the complex phase creations in the natural massive sul phide deposits of hydrothermal origin. We studied the multistage struc tural magnetic transformations of pyrite on the air within the tempera ture interval of 20-700 degrees C by means of Mossbauer spectroscopy, thermomagnetic analysis and x-ray diffraction. The emergency of hexago nal and monoclinic nonstoichiometric pyrrhotites with varied degree of vacancy ordering and disordering have been observed. The Curie points of those metastable phases change within the limits of 120-240 degree s C for hexagonal and within 320-480 degrees C for monoclinic pyrrhoti tes.