Characterization and leaching behavior of mixed oxide-sulfide zinc ore from Hakkari-Türkiye

Besides sulfide ores, non-sulfide and mixed oxide-sulfide zinc have become important resources for zinc. Prior to processing these types of ores using non-conventional methods, chemical and mineralogical characterization is required. In this study, the chemical and mineralogical characteristics of domestic mixed zinc ore were studied using optical microscopy, SEM, XRD, ICP-OES, XRF, FT-IR and TG-DTA. The results of these analyses provide valuable information such as mineral composition, oxide percentage, grain size, mineral constituents, and thermal decomposition, which are essential for determining the mineral processing method. For instance, the ore mineralogy primarily consists of carbonate (smithsonite; ZnCO<sub>3</sub>), and less sulfide (sphalerite; ZnS) and oxide (Zincite; ZnO). Besides, the dissolution behavior of the ore was investigated in both alkaline (NaOH, NH<sub>4</sub>OH) and acidic (HCl, H<sub>2</sub>SO<sub>4</sub>) solutions under different leaching conditions including concentrations (1, 2, 4, 6 M (N)), particle size (−106 μm, −300 μm), leaching time (30, 60, 120 min), leaching temperature (25, 50, 75°C), and solid/liquid ratio (1:5, 1:10, 1:15 g/dm3). In alkaline solutions, it was observed that the dissolution rate increased with higher concentrations; however, this increase was negligible in acidic solutions. The maximum leaching rates of zinc under constant conditions (−300 μm, 60 min., 25°C, 1:10 g/dm<sup>3</sup>) were achieved at 68.68%, 55.42%, 74.78%, and 75.45% for NaOH (4M), NH<sub>4</sub>OH (6M), HCl (4M), and H<sub>2</sub>SO<sub>4</sub> (4N) solutions, respectively.