Obtaining the Zinc Ammine Carbonate, Hydrozincite, and Zinc Oxide from Dolomite-Containing Smithsonite Ore by Hydrometallurgical Methods
Year: 2026
Type: article
Abstract: In this study, the effects of ammonia concentration and solid/liquid ratio on the dissolution behavior of zinc from local dolomite-containing smithsonite (ZnCO3) ore samples in aqueous ammonia solutions were investigated at room temperature by X-ray fluorescence (XRF), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy analyses. The findings revealed a significant increase in the dissolution ratio of zinc, rising from 43.6% to 56.3% with an increase in ammonia concentration from 5.0 to 6.0 M. Subsequently, a maximum zinc dissolution ratio of 61.2% was achieved after dissolution in a 12 M NH3 solution. The XRD pattern of the residue obtained after dissolution in 6.0 M NH3 solution for 120 min, under a solid/liquid ratio of 0.15 g/mL (the optimized condition), indicated substantial dissolution of the smithsonite phase in the ore sample. At the same time, the gangue minerals, goethite, and dolomite, remained predominantly undissolved. This observation underscores the selectivity of ammonia solution for zinc dissolution. Concurrently, dissolution ratios of cadmium were also determined. In the second part of the study, precipitation tests were conducted on dissolved zinc, carbonate, and ammonia-containing pregnant solutions obtained after selected dissolution experiments. By complete evaporation of the pregnant solutions at low temperatures, i.e., 70°C, relatively pure solid zinc ammine carbonate (Zn(NH3)CO3) precipitates. At higher temperatures (i.e., 140-170°C), quite pure solid hydrozincite (i.e., zinc carbonate hydroxide Zn5(CO3)2(OH)6) precipitates could be prepared. High-temperature heating of Zn(NH3)CO3 and Zn5(CO3)2(OH)6 precipitates at 400°C generated single-phase zinc oxide (ZnO). The chemical compositions, FT-IR spectra, and scanning electron microscope (SEM) photographs of some of the precipitates were also presented
Source: Acta Montanistica Slovaca
Author: Arman EHSANI
Institution: Adana Science and Technology University
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7224005338