As a continuation of our long-term investigation of the thermodynamics, kinetics and mechanism of metal sulphide oxidation the present paper present results on the Marmatite oxidation, using DTA, TGA, X-ray diffraction analysis, optical and scanning electron microscopy (SEM). The paper presents three-dimensional diagrams of partial pressures of SO2 and O-2 against T for the Zn-Fe-S-O system. A multi-layer oxide product of high porosity (over 30%) was obtained as shown by scanning electron microscopy. On the basis of kinetic studies and electron microscopy, it was found that under the conditions of zinc concentrates fluid bed roasting, the oxidation of marmatite takes place in a kinetically controlled regime.