Kinetics of sulphuric acid leaching of a zinc silicate calcine

Souza, Adelson Dias de; Piña, Patricia; Lima, E.V.O.; Silva, C.A. da; Leão, Versiane Albis

doi:10.1016/j.hydromet.2007.08.005

Cited by 82 publications

(43 citation statements)

References 21 publications

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“…After 60 min, the leaching ratio reached 100% in the H 2 SO 4 concentration range of 0.5 to 1 M, whereas the leaching rate was 83.5% at a H 2 SO 4 concentration of 0.1 M. The effect of H 2 SO 4 concentration found in these investigations agrees well with the results of other investigators [15,16,18]. If all of the zinc in the MOVs is leached, the total zinc concentration will be 0.11 M in the leaching solution because the mole ratio of H 2 SO 4 to zinc ions is 1.…”

Section: Effect Of H 2 So 4 Concentrationsupporting

confidence: 91%

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Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Kim

Lee

2016

Metals

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Abstract:The leaching kinetics of zinc from zinc oxide-based metal oxide varistors (MOVs) was investigated in H 2 SO 4 at atmospheric pressure. Kinetics experiments were carried out at various agitation speeds, particle sizes, initial H 2 SO 4 concentrations, and reaction temperatures. It was determined that the leaching rate of zinc was independent of agitation speed above 300 rpm and also independent of particle size below 105 µm, whereas it dramatically increased with an increasing H 2 SO 4 concentration. Except for when the H 2 SO 4 concentration was varied, the m-values were almost constant at varying agitation speeds (m-values: 0.554-0.579), particle sizes (m-values: 0.507-0.560) and reaction temperature (m-values: 0.530-0.560) conditions. All of the m-values in these experiments were found to be below 0.580. Therefore, it is proposed that the extraction of zinc is a diffusion-controlled reaction. The leaching kinetics followed the D3 kinetic equation with a rate-controlling diffusion step through the ash layers, and the corresponding apparent activation energy was calculated as 20.7 kJ/mol in the temperature range of 313 K to 353 K.

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Section: Effect Of H 2 So 4 Concentrationsupporting

confidence: 91%

“…However, this study was not sufficient from an industrial point of view. Similar investigations have been carried out by other research groups [16][17][18]. However, these studies focused on zinc leaching from electric arc furnace dust (EAF dust) or zinc ores.…”

Section: Introductionmentioning

confidence: 74%

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Kim

Lee

2016

Metals

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“…Of these models, the previously established shrinking-core model plays an important role in the fluid-solid system and has been applied in the study of leaching for various sulfides [34][35][36][37][38][39][40][41]. Therefore, the shrinking-core model was applied to describe the leaching kinetics for this experiment.…”

Section: Kinetics Of Copper Leaching For the Mechanically Activated Cusmentioning

confidence: 99%

“…Therefore, the shrinking-core model was applied to describe the leaching kinetics for this experiment. The simplified equations of the shrinking-core model can be expressed as follows [41,42]: As shown in Figure 3, the leachability increased as an increase of grinding speed at all leaching temperature conditions, from 50 to 80 • C, even though the specific surface area (SSA) of CuS ground at 700 rpm for 15 min was lower than that of CuS ground at 300 rpm for 15 min (Table 1). These results imply that the Cu leachability of CuS can be improved by intensive grinding and it increases in sequence of grinding intensity.…”

Section: Kinetics Of Copper Leaching For the Mechanically Activated Cusmentioning

confidence: 99%

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Effect of Mechanical Activation on the Kinetics of Copper Leaching from Copper Sulfide (CuS)

Lee

Kim

et al. 2018

Metals

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Abstract:The effect of mechanical activation on the copper leaching of copper sulfide, CuS, in 1 M HNO 3 (slurry density: 10 g/L) was investigated by analysis of the leachability and the apparent activation energy. Mechanical activation produced an increase in the leachability and a decrease of the activation energy in this leaching reaction. The leachability increased proportionally to the degree of mechanical activation, reaching 96.6% leaching within 60 min at 80 • C from CuS ground at 700 rpm for 15 min. This leaching process was controlled by surface chemical reaction following the shrinking-core model. The apparent activation energy of leaching for CuS (71.5 kJ/mol) in the range of 50 to 80 • C decreased with an increase of the degree of mechanical activation, reaching 44.3 kJ/mol for Cu leaching from CuS ground at 700 rpm for 15 min.

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Fractionation and leachability of heavy metals from aged and recent Zn metallurgical leach residues from the Três Marias zinc plant (Minas Gerais, Brazil)

Sethurajan

Huguenot²,

Lens

et al. 2016

Environ Sci Pollut Res

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Various mineral processing operations to produce pure metals from mineral ores generate sludges, residues, and other unwanted by-products/wastes. As a general practice, these wastes are either stored in a reservoir or disposed in the surrounding of mining/smelting areas, which might cause adverse environmental impacts. Therefore, it is important to understand the various characteristics like heavy metal leaching features and potential toxicity of these metallurgical wastes. In this study, zinc plant leach residues (ZLRs) were collected from a currently operating Zn metallurgical industry located in Minas Gerais (Brazil) and investigated for their potential toxicity, fractionation, and leachability. Three different ZLR samples (ZLR1, ZLR2, and ZLR3) were collected, based on their age of production and deposition. They mainly consisted of Fe (6-11.5 %), Zn (2.5 to 5.0 %), and Pb (1.5 to 2.5 %) and minor concentrations of Al, Cd, Cu, and Mn, depending on the sample age. Toxicity Characteristic Leaching Procedure (TCLP) results revealed that these wastes are hazardous for the environment. Accelerated Community Bureau of Reference (BCR) sequential extraction clearly showed that potentially toxic heavy metals such as Cd, Cu, Pb, and Zn can be released into the environment in high quantities under mild acidic conditions. The results of the liquid-solid partitioning as a function of pH showed that pH plays an important role in the leachability of metals from these residues. At low pH (pH 2.5), high concentrations of metals can be leached: 67, 25, and 7 % of Zn can be leached from leach residues ZLR1, ZLR2, and ZLR3, respectively. The release of metals decreased with increasing pH. Geochemical modeling of the pH-dependent leaching was also performed to determine which geochemical process controls the leachability/solubility of the heavy metals. This study showed that the studied ZLRs contain significant concentrations of non-residual extractable fractions of Zn and can be seen as a potential secondary resource for Zn.

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Kinetics of sulphuric acid leaching of a zinc silicate calcine

Cited by 82 publications

References 21 publications

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Leaching Kinetics of Zinc from Metal Oxide Varistors (MOVs) with Sulfuric Acid

Effect of Mechanical Activation on the Kinetics of Copper Leaching from Copper Sulfide (CuS)

Fractionation and leachability of heavy metals from aged and recent Zn metallurgical leach residues from the Três Marias zinc plant (Minas Gerais, Brazil)

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