Changes in Bornite (Cu5FeS4) after Heating in Air: Mossbauer Effect Study

The phase transitions and structural behaviour in natural bornite sample were investigated after heat treatment in air in a temperature range of (180 divided by 500) degrees C using high-resolution Faraday, X-ray diffraction and (5)7Fe Mossbauer spectroscopy studies. X-ray diffraction and the Mossbauer spectroscopy results show that polymorph phases can exist only at high temperatures, and at a temperature of 220 degrees C a process of decomposition of bornite structure starts. Hematite is a main Fe-bearing phase and Cu is located mainly in cooper oxides present in the sample after annealing at 500 degrees C.