Determination of the Optimum Conditions for the Leaching of Nonsulfide Zinc Ores (High-SiO₂) in Ammonium Carbonate Media

Abstract

The Taguchi method was used as the experimental design to determine the optimum conditions for the dissolution of nonsulfide zinc ores in ammonium carbonate solution for high recovery of zinc, and to minimize the extraction of iron and lead. The experimental conditions were studied in the range of 35−75 °C for reaction temperature (T), 300−800 rpm for stirring speed (R), 2−4 mol for ammonium carbonate concentration (C), 30−90 min for reaction time (t), and 9−11 for pH (denoted as pH). The obtained optimum conditions from this study were T = 45 °C, R = 300 rpm, C = 3 mol, t = 45 min, and pH 10. Under these conditions, the optimum dissolution of zinc was ∼92%. To minimize iron and lead dissolution while keeping the dissolution of zinc, three series of experiments, in alternative conditions, were performed. Total optimum conditions that obtained from this study were T = 45 °C, R = 300 rpm, C = 2 M, t = 45 min, and pH 11.

Investigation of the use of ammonium acetate as an alternative lixiviant in the leaching of malachite ore

“…Thus, ammonia allows for selective extraction of the copper from ore, leaving the undesired components in the residue [19,25,26]. Furthermore, some metals, which pass into the solution during dissolution process, precipitate because of the higher pH of solutions containing ammonia.…”

Preparation of different zinc compounds from a smithsonite ore through ammonia leaching and subsequent heat treatment

“…Although there are several studies in the related literature on the leaching of zinc from smithsonite ores in sodium hydroxide solutions under different experimental conditions (Frenay, 1985;Zhao and Stanforth, 2000;Ghasemi and Azizi, 2018;Ehsani et al, 2019;Kumas et al, 2020), the studies that directly leach the ore in ammoniacal solutions including an ammonium salt (Frenay, 1985;Ju et al, 2005;Moghaddam et al, 2005;Feng et al, 2007;Xia et al, 2015) and in only aqueous ammonia solutions (Frenay, 1985; are scarce. Frenay (1985) studied the leaching behaviour of a Belgian smithsonite ore (12.5% Zn) in ammonia solutions (NH3 concentration: 0.4-4.7 M; 120 min; solid/liquid ratio: 0.088 g/mL; 25°C; ore particle size: -400 μm) and obtained zinc leaching ratios changing between 18 and 80%.…”

Kinetics of Dissolution of Tenorite in Ammonium Media

“…Several investigations have been developed using different ammonia reagents, such as malachite leaching (Bingö l et al 2005, Ekmekyapar et al 2003, low grade copper ore (Wei et al 2010) and casting powders (Morales et al 2009), and even works for the treatments of other materials such as zinc oxides (Lozano et al 1999;Moghaddam et al 2005). Until now, no previous work has been developed on tenorite ammonia leaching.…”