A comparison of the kinetics and mechanism of acid leaching of sphalerite containing low and high concentrations of iron
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| Title: | A comparison of the kinetics and mechanism of acid leaching of sphalerite containing low and high concentrations of iron |
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| Authors: | Weisener, Christopher G.1, Smart, Roger St.C.1, Gerson, Andrea R. Andrea.Gerson@unisa.edu.au |
| Source: | International Journal of Mineral Processing. Nov2004, Vol. 74 Issue 1-4, p239-249. 11p. |
| Subjects: | Mass spectrometry, Spectrum analysis, Electron microscopy, Hydrogen-ion concentration |
| Abstract: | The leaching behaviour of three Fe-containing sphalerite minerals (0.45, 11.40, and 12.90 wt.% Fe) was investigated at pH 1 in O2-purged HClO4 from 25 to 85 °C. For all three sphalerite samples, the leach data closely fitted a rate expression which incorporates both a shrinking sphere term and rate control via diffusion through a reacted surface layer. The leach rate increased with increasing Fe content of the sphalerite. At 85 °C after 168 h of leaching, 0.89 of the Zn had been leached from the 12.90 wt.% Fe-containing sphalerite while, over the same period of time, 0.49 of the Zn had leached from the 0.45 wt.% Fe-containing sphalerite.The activation energies for leaching decreased with increasing Fe content of the sphalerite (i.e. for Zn leaching 63±6, 50±7 and 39±2 kJ mol-1 for the 0.45, 11.40 and 12.90 wt.% Fe-containing sphalerite samples, respectively). The activation energy of leaching of Fe and Zn was within experimental error for the 11.40 and 12.90 wt.% sphalerite samples. The solution Fe content was not measured reliably for the 0.45 wt.% Fe-containing sphalerite.The leaching mechanisms have been interpreted as a function of surface speciation, which was analysed using time of flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) for samples leached at 85 °C. The decrease in Zn dissolution rate on leaching is attributed to the formation and growth of a polysulfide surface layer, which forms during the initial rapid leach period. The formation of elemental sulfur during the subsequent slow leach period does not further affect the leach rates. The concentrations of polysulfide and elemental sulfur that form increase with increasing Fe concentration as expected from the higher leach rates. The formation of polysulfide and elemental sulfur on the ZnS surface consumes H+ (via conversion to H2O) thus decreasing solution acidity. [Copyright &y& Elsevier] |
| Copyright of International Journal of Mineral Processing is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 14811200 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: A comparison of the kinetics and mechanism of acid leaching of sphalerite containing low and high concentrations of iron – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Weisener%2C+Christopher+G%2E%22">Weisener, Christopher G.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Smart%2C+Roger+St%2EC%2E%22">Smart, Roger St.C.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Gerson%2C+Andrea+R%2E%22">Gerson, Andrea R.</searchLink><i> Andrea.Gerson@unisa.edu.au</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22International+Journal+of+Mineral+Processing%22">International Journal of Mineral Processing</searchLink>. Nov2004, Vol. 74 Issue 1-4, p239-249. 11p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Mass+spectrometry%22">Mass spectrometry</searchLink><br /><searchLink fieldCode="DE" term="%22Spectrum+analysis%22">Spectrum analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Electron+microscopy%22">Electron microscopy</searchLink><br /><searchLink fieldCode="DE" term="%22Hydrogen-ion+concentration%22">Hydrogen-ion concentration</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The leaching behaviour of three Fe-containing sphalerite minerals (0.45, 11.40, and 12.90 wt.% Fe) was investigated at pH 1 in O2-purged HClO4 from 25 to 85 °C. For all three sphalerite samples, the leach data closely fitted a rate expression which incorporates both a shrinking sphere term and rate control via diffusion through a reacted surface layer. The leach rate increased with increasing Fe content of the sphalerite. At 85 °C after 168 h of leaching, 0.89 of the Zn had been leached from the 12.90 wt.% Fe-containing sphalerite while, over the same period of time, 0.49 of the Zn had leached from the 0.45 wt.% Fe-containing sphalerite.The activation energies for leaching decreased with increasing Fe content of the sphalerite (i.e. for Zn leaching 63±6, 50±7 and 39±2 kJ mol-1 for the 0.45, 11.40 and 12.90 wt.% Fe-containing sphalerite samples, respectively). The activation energy of leaching of Fe and Zn was within experimental error for the 11.40 and 12.90 wt.% sphalerite samples. The solution Fe content was not measured reliably for the 0.45 wt.% Fe-containing sphalerite.The leaching mechanisms have been interpreted as a function of surface speciation, which was analysed using time of flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) for samples leached at 85 °C. The decrease in Zn dissolution rate on leaching is attributed to the formation and growth of a polysulfide surface layer, which forms during the initial rapid leach period. The formation of elemental sulfur during the subsequent slow leach period does not further affect the leach rates. The concentrations of polysulfide and elemental sulfur that form increase with increasing Fe concentration as expected from the higher leach rates. The formation of polysulfide and elemental sulfur on the ZnS surface consumes H+ (via conversion to H2O) thus decreasing solution acidity. [Copyright &y& Elsevier] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of International Journal of Mineral Processing is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.minpro.2003.12.001 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 11 StartPage: 239 Subjects: – SubjectFull: Mass spectrometry Type: general – SubjectFull: Spectrum analysis Type: general – SubjectFull: Electron microscopy Type: general – SubjectFull: Hydrogen-ion concentration Type: general Titles: – TitleFull: A comparison of the kinetics and mechanism of acid leaching of sphalerite containing low and high concentrations of iron Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Weisener, Christopher G. – PersonEntity: Name: NameFull: Smart, Roger St.C. – PersonEntity: Name: NameFull: Gerson, Andrea R. IsPartOfRelationships: – BibEntity: Dates: – D: 19 M: 11 Text: Nov2004 Type: published Y: 2004 Identifiers: – Type: issn-print Value: 03017516 Numbering: – Type: volume Value: 74 – Type: issue Value: 1-4 Titles: – TitleFull: International Journal of Mineral Processing Type: main |
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