University of Tehran International Journal of Mining and Geo-Engineering 2345-6930 59 2 2025 06 01 The assessment of zinc precipitation from sulfate solutions using magnesium-rich ores 115 118 102418 10.22059/ijmge.2025.395591.595256 EN Saeid Karimi Department of Metallurgy and Materials Engineering, Hamedan University of Technology, Hamedan, Iran. Bahram Behnajady Research Centre of Advanced Materials, Faculty of Materials Engineering, Sahand University of Technology, Sahand New Town, Iran. Javad Moghaddam Materials and Metallurgical Engineering Department, University of Zanjan, Zanjan, Iran. Journal Article 2025 05 19 This study systematically investigates the mechanisms and optimization of zinc precipitation from sulfate solutions using magnesium-containing ores. The dominant reaction pathway leads to the formation of zinc hydroxysulfate (Zn₅(OH)₆(SO₄)₂) at moderate pH (4–6.5), as confirmed by a consistent final pH of 6.5 in all experiments. Temperature critically influences reaction kinetics, with 80 °C identified as optimal for maximizing zinc recovery (73.4 %) and ensuring effective magnesium participation in precipitation reactions. Process efficiency is governed by ore dosage, where 100 g/L of magnesium-rich ore yields peak zinc recovery, beyond which marginal improvements occur. Time-dependent studies reveal that 150 minutes represents the practical equilibrium for zinc precipitation at 80 °C, achieving 73.4% recovery with diminishing returns thereafter. Key findings demonstrate that controlled parameters—pH 6.5, 80°C, 150-min reaction time, and optimized ore dosage—collectively enhance zinc recovery while minimizing reagent consumption and energy costs. Under the optimized conditions (T = 80°C, ore dosage = 100 g/l, time = 150 minutes), the magnesium content demonstrated a significant reduction from 7.0 g to 5.1 g, corresponding to an absolute decrease of 1.9 g (27.1% decrement), which clearly indicates effective magnesium participation in the precipitation process, where the combination of elevated temperature and controlled ore dosage synergistically enhanced magnesium removal efficiency while minimizing residual content, ultimately contributing to improved process performance. https://ijmge.ut.ac.ir/article_102418_3b6c60a30453784593222256f780fc2f.pdf