The effect of As(III) and As(V) on the batch bioleaching of a pyrite-arsenopyrite concentrate

 

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dc.contributor.author Breed, A W
dc.contributor.author Glatz, A
dc.contributor.author Hansford, G S
dc.contributor.author Harrison, S T L
dc.date.accessioned 2016-08-17T08:32:42Z
dc.date.available 2016-08-17T08:32:42Z
dc.date.issued 1996
dc.identifier http://dx.doi.org/10.1016/S0892-6875(96)00119-7
dc.identifier.citation Breed, A. W., Glatz, A., Hansford, G. S., & Harrison, S. T. L. (1996). The effect of As (III) and As (V) on the batch bioleaching of a pyrite-arsenopyrite concentrate. Minerals Engineering, 9(12), 1235-1252. en_ZA
dc.identifier.issn 0892-6875 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/21279
dc.description.abstract The bioleaching of arsenical gold-bearing sulphide ores and concentrates solubilises iron, arsenic and sulphur. Previous work has shown that high concentrations of iron and arsenic in solution inhibit bacterial growth, with As(III) reported to inhibit bacteria to a greater degree than As(V). Batch bioleaching experiments were carried out over periods of one month. Varying quantities of either 0.020–0.040 M As(III) or 0.107–0.220 M As(V), were added to a slurry, consisting of a pyrite-arsenopyrite concentrate (20% solids (m.v−1)) in a nutrient solution. The slurry was inoculated with a culture, consisting primarily of Leptospirillum ferrooxidans and Thiobacillus thiooxidans. The culture was obtained from a continuous bioleaching mini-plant treating the same concentrate. The results obtained were compared with those of a culture to which no arsenic was added. The effect of the added arsenic was determined by monitoring three parameters: the oxygen utilisation rate, rO2, of the culture, the rate at which the arsenic in the concentrate was solubilised and the speciation of the dissolved arsenic. The results suggest that the nature of the As(III) and As(V) toxicity is different. The addition of the culture to a slurry containing As(III) resulted in a reduced rate of bacterial oxidation. However, the addition of the culture to a slurry containing As(V) resulted in both a lag phase and a reduced rate of bacterial oxidation. At sufficiently high dosages of As(III) and As(V) the maximum oxygen utilisation rate, rO2max, of the culture was also affected. The results indicate that As(V) toxicity, and the relative toxicity of As(III) and As(V) to a mixed culture, appear to be affected by the availability of an energy source. Hence the toxicity of As(III) is not necessarily in the region of three times that of As(V). Furthermore, the results suggest that the mechanism of arsenic resistance may be attributed to the Pst+ Pit− mutations and an energy dependent efflux pump. en_ZA
dc.language eng en_ZA
dc.publisher Elsevier en_ZA
dc.rights Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) *
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/4.0/ en_ZA
dc.source Minerals Engineering en_ZA
dc.source.uri http://www.journals.elsevier.com/minerals-engineering/
dc.subject.other Bacteria
dc.subject.other bioleaching
dc.subject.other oxidation
dc.subject.other sulphide ores
dc.subject.other extractive metallurgy
dc.title The effect of As(III) and As(V) on the batch bioleaching of a pyrite-arsenopyrite concentrate en_ZA
dc.type Journal Article en_ZA
dc.date.updated 2016-08-16T10:18:40Z
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
uct.type.filetype Text
uct.type.filetype Image


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