Thermal behavior of zinc sulfide concentrates with different iron content at oxidative roasting

• XRD, DTA, TGA, Mössbauer spectroscopy studies of six zinc sulfide concentrates are made.
• The content of iron as inclusions in the crystal lattice of ZnS was measured.
• Oxidation of zinc concentrates shows that iron inclusions mainly influences the process of zinc ferrite formation.
• With the use of the Web-based information system charges of concentrates are calculated and recommended for the practice.

Processing of sulfide concentrates with high iron content in the hydrometallurgy of zinc increases the amount of obtained cakes containing 15–20% Zn and 25–30% Fe. The main reason for this undesirable process is the presence of a part of the zinc as insoluble ZnF2O4.In this regard, 6 zinc concentrates of different origins were investigated using Mössbauer spectroscopy as well as chemical, XRD, DTA and TGA analyses. The relation between the phase content and the received TG and DTA curves, as well as the behavior of the main phases in the concentrates during their oxidation was established. On the basis of the Mössbauer spectra, the iron containing phases and their influence on the oxidation process were determined.The results are used to choose the charge of concentrates for optimal oxidative roasting in fluidized bed furnace and for minimizing ferrite formation.