The kinetics of zinc silicate leaching in sodium hydroxide

Santos, Fabiano Mariel Fernandes dos; Piña, Pablo; Porcaro, Rodrigo Rangel; Oliveira, Victor de Alvarenga; Silva, Carlos Antônio da; Leão, Versiane Albis

doi:10.1016/j.hydromet.2010.01.010

Cited by 72 publications

(23 citation statements)

References 25 publications

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“…The small difference is likely ascribed to the negligible change of the surface area and the porosity of the solid (Table I). Santos et al [13] also verified the insignificance of particle size on the leaching kinetics of zinc silicate ores containing willemite in alkaline solution. Figure 4 shows the leaching behavior of willemite at 288 K to 328 K (15°C to 55°C).…”

Section: Effect Of Particle Sizementioning

confidence: 85%

“…The similar result was observed by Abdel-Aal [9] when the leaching experiments of zinc silicate ore containing willemite and hemimorphite were carried out. Souza et al [10] and Santos et al [13] studied the leaching of zinc silicate ore containing willemite and verified that temperature has a great effect on the zinc extraction both in acid and in alkaline solutions.…”

Section: Effect Of Particle Sizementioning

confidence: 97%

“…Moreover, the value determined in the present work is likely derived from the parallel nature of diffusion and reaction in porous solid as shown in Eq. [13], in which the overall rate (k 0 ) can be expressed as follows [24] :…”

Section: F Kinetic Modelmentioning

confidence: 99%

“…Santos et al [13] and Chen et al [14] investigated the leaching kinetics of zinc silicate ores in sodium hydroxide. They concluded that the process is chemically controlled.…”

Section: Introductionmentioning

confidence: 99%

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Leaching Kinetics of Willemite in Ammonia-Ammonium Chloride Solution

Ding

Yin

et al. 2011

Metall Mater Trans B

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The leaching kinetics of willemite in ammonia-ammonium chloride solution was investigated. The effects of the ammonia-ammonium ratio, particle size, temperature, and total ammonia concentration on the leaching rate of willemite were determined. The results show that the optimum ammonia-ammonium ratio is 1:2 over the studied range. The zinc extraction increases with the reduction of particle size and with the increase of temperature and the total ammonia concentration. Leaching kinetics indicate that the grain pore model could be adopted to describe the leaching process, and diffusion is the main rate-controlling step. The apparent activation energy was determined to be 54.47 ± 6.39 kJ/mol and a reaction order with respect to NH 3 (aq) was 3.16 ± 0.40, both of which are likely a result of the parallel nature of the chemical reaction and diffusion in porous solids, even if the chemical reaction is not the rate-controlling step.

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Section: Effect Of Particle Sizementioning

confidence: 85%

Section: Effect Of Particle Sizementioning

confidence: 97%

Section: F Kinetic Modelmentioning

confidence: 99%

“…Santos et al [13] and Chen et al [14] investigated the leaching kinetics of zinc silicate ores in sodium hydroxide. They concluded that the process is chemically controlled.…”

Section: Introductionmentioning

confidence: 99%

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Leaching Kinetics of Willemite in Ammonia-Ammonium Chloride Solution

Ding

Yin

et al. 2011

Metall Mater Trans B

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“…The application of alkaline leaching techniques has become an increasingly important aspect in the recovery of base and precious metals from complex low grade zinc oxide ores (Santos et al, 2010;Ding et al, 2010;Yin et al, 2010). However, alkaline leaching processing is often confronted with the problem of low-grade complex ores, especially zinc silicate.…”

Section: Introductionmentioning

confidence: 99%

LEACHING Zn FROM THE LOW-GRADE ZINC OXIDE ORE IN NH3-H3C6H5O7-H2O MEDIA

Peng

Zhang

et al. 2016

Braz. J. Chem. Eng.

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-In this research, the effect of different citric acid concentrations, ammonia concentration, temperature, leaching time, stirring speed and liquid-to-solid ratio on the zinc leaching from low-grade zinc oxide ore in a NH 3 -H 3 C 6 H 5 O 7 -H 2 O system were studied. The results showed that the zinc leaching rate is only 4.7% when the citric acid concentration is 0 M, and the leaching efficiency of Zn increased with increasing citric acid concentration. Under the conditions: citric acid concentration of 1.0 M, ammonia concentration of 6 M, temperature of 25 °C, leaching time of 60 min, stirring speed of 300 rpm and the starting solid-to-liquid ratio of 1:5, 81.2% of Zn is leached. The mineralogical changes of the low-grade zinc oxide ores during the processes were characterized by X-ray fluorescence (XRF), X-ray powder diffraction (XRD), Scanning Electron Microscopy associated with Energy Dispersive Spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR). From the evidence we deduced that citric ions complexed with zinc ions, forming a Zn-citrate complex. As a result, the zinc leaching rate was improved without the risk of pollution or pretreatment. This makes it as a good choice for a more ecological treatment of hemimorphite.

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