Leaching of hemimorphite in NH3–(NH4)2SO4–H2O system and its mechanism

Liu, Zhiyong; Liu, Zhihong; Li, Qihou; Yang, Tianzu; Zhang, Xu

doi:10.1016/j.hydromet.2012.06.004

Cited by 30 publications

(5 citation statements)

References 21 publications

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“…In recent years, the extraction of zinc from zinc oxide ores with ammoniacal solution is a hotspot in the zinc recovery process. The extraction process in ammonia-with or without ammonium-has been researched a great deal [13][14][15][16]. However, the leaching kinetics of hemimorphite in ammonium chloride have never been studied.…”

Section: Introductionmentioning

confidence: 99%

Leaching Kinetics of Hemimorphite in Ammonium Chloride Solution

Zhao¹,

Yang²,

Chen³

et al. 2017

Metals

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The leaching kinetics of hemimorphite (Zn 4 Si 2 O 7 (OH) 2 •H 2 O) in ammonium chloride solution was presented in detail. Effects of stirring speed (150-350 rpm), leaching temperature (75-108 • C), particle size of hemimorphite (45-150 µm), and the concentration of ammonium chloride (3.5-5.5 mol/L) on the zinc extraction rate were studied. The zinc extraction rate enhanced slightly with the increase in stirring speed, but increased significantly with an increase in the leaching temperature and ammonium chloride concentration. Zinc extraction was enhanced significantly in the first 60 min with decreasing particle size, but had little effect on the leaching process after 60 min. Scanning electron microscopy (SEM) analysis showed that some silica gel formed in the leaching process was not separated from the hemimorphite surface, but covered some of the active particle surface. The Elovich equation successfully described the leaching kinetics of hemimorphite in ammonium chloride solution with an apparent activation energy of 405.14 kJ/mol at temperatures of 75-90 • C and 239.61 kJ/mol at temperatures of 95-108 • C, which is characteristic for a chemically-controlled process. Silica gel is generated at temperatures of 75-90 • C and decomposed into silica at temperatures of 95-108 • C.

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Section: Introductionmentioning

confidence: 99%

Leaching Kinetics of Hemimorphite in Ammonium Chloride Solution

Zhao¹,

Yang²,

Chen³

et al. 2017

Metals

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“…Ammoniacal solutions are commonly used to deal with the relative refractory ores due to the formation of stable metal amine complexes, which leads to higher solubility in most cases. − With the extensive application of ammonia leaching technology in the hydrometallurgy process, more and more attention is paid to separate and recover metal ions from ammoniacal solutions by solvent extraction . Hydrophobic β-diketones are well-known versatile chelating reagents for various metal ions because of their strong chelating ability.…”

Section: Introductionmentioning

confidence: 99%

Activity Coefficient of β-Diketone in Ammoniacal Solutions at 298.15 K

Chen

et al. 2013

J. Chem. Eng. Data

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The solubility of 4-ethyl-1-phenyl-1,3-octadione in pure water, (NH 4 ) 2 SO 4 , NH 3 (aq), and (NH 4 ) 2 SO 4 −NH 3 −H 2 O solutions was measured by means of isothermal solution method at 298.15 K. The investigated total ammonia concentration ranges of NH 3 , (NH 4 ) 2 SO 4 , and (NH 4 ) 2 SO 4 −NH 3 −H 2 O system were up to 1.8053 mol•L −1 , 3.0135 mol•kg −1 , and 6.4 mol•kg −1 , respectively. The experimental results indicate that the solubility of 4-ethyl-1-phenyl-1,3-octadione in NH 3 and (NH 4 ) 2 SO 4 −NH 3 −H 2 O solutions increases with the increase of total ammonia concentration. In contrast, its solubility in (NH 4 ) 2 SO 4 solution decreases with the increase of the ammonium sulfate concentration. The Pitzer model was adopted to correlate the dependency of the solubility with the activity coefficients. The parameters obtained by the least-squares method can explain the salting effect phenomenon and can be used to calculate and predict the activity coefficients of 4ethyl-1-phenyl-1,3-octadione in ammoniacal solutions by the Pitzer model.

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“…In the Pb-Zn industrial concentrating, the lead sulfide, zinc sulfide, and often lead oxide minerals can be effectively enriched by traditional mineral processing techniques, while the processing of zinc oxide has been a complex challenging, especially when the hemimorphite (Zn4(Si2O7)(OH)2) at high content was found in the ores (Frenay, 1985), which results in the low recovery of total zinc in concentrating plants. Although sulfidization xanthate flotation is one of the most proposed technologies for economicly and selectively enriching zinc oxide minerals, the flotation is still low efficient for recovering hemimorphite in the most mining enterprises (Jia et al, 2017;Liu et al, 2016;Liu et al, 2012;Navidi Kashani and Rashchi, 2008;Önal et al, 2005;Shiel et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Lead species formation on pure hemimorphite surface and its performance for subsequent sulfidization

Liang,

Zhang,

Xian

et al. 2024

Physicochem. Probl. Miner. Process.

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Hemimorphite is important-supplementary resource for the commercial zinc production, but it easy loses into tailings due to extreme difficulty for its surface sulfidization. Adding active metal ions after sulfidization have been widely proposed for enhancing hemimorphite floatability, but its desired efficiency in flotation practice has not yet been completely achieved caused by the instability of sulfide layer. Whereas pre-adsorption of active metal ions to modify the hemimorphite surface has strong potential to make up for this shortcoming. Herein, the feasibility and appropriate environment of free Pb2+ for modifying the pure hemimorphite surface was evaluated. Subsequently, the performance of Pb2+ adsorption for enhancing sulfidization stability and floatability of hemimorphite were investigated. The X-ray photoelectron spectroscopy results indicated that the Pb2+ adsorption on hemimorphite surface was achieved through the Pb ions displacement for Zn ions, and it was bond to oxygen-containing groups on hemimorphite surface. Such adsorption was strengthened with the increasing of solution pH, owing to the abundant Pb hydroxyl species precipitated on mineral under alkaline conditions, in term of the results of visual MINTEQ modeling and time-of-flight secondary-ion mass spectrometry. In addition, the X-ray photoelectron spectroscopy results showed dominant Pb hydroxyl species further reacted with sulfur during subsequent sulfidization to generate much more S species than that of without Pb2+ pre-modification. Meanwhile, such sulfide layer composed by Pb2+ on the mineral surface presented much higher stability than Zn-S species, which was verified via adsorption and desorption tests. As a result, the sulfidization and flotation recovery of hemimorphite increased after Pb2+ pre-adsorption.

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Leaching of hemimorphite in NH3–(NH4)2SO4–H2O system and its mechanism

Cited by 30 publications

References 21 publications

Leaching Kinetics of Hemimorphite in Ammonium Chloride Solution

Leaching Kinetics of Hemimorphite in Ammonium Chloride Solution

Activity Coefficient of β-Diketone in Ammoniacal Solutions at 298.15 K

Lead species formation on pure hemimorphite surface and its performance for subsequent sulfidization

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