An experimental strategy to determine galvanic interactions affecting the reactivity of sulfide mineral concentrates

Cruz, Roel; Luna-Sánchez, Rosa María; Lapidus, G.T.; González, Ignacio; Monroy, Marcos

doi:10.1016/j.hydromet.2005.03.006

Cited by 73 publications

(40 citation statements)

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“…These galvanic effects are important in the aqueous processing of ores and minerals, such as flotation and leaching. Galvanic interactions can substantially increase both leaching rate of and metal recovery from different minerals (Cruz et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Bioleaching of a complex nickel–iron concentrate by mesophile bacteria

Santos

Barbosa

Souza³

et al. 2006

Minerals Engineering

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Section: Introductionmentioning

confidence: 99%

Bioleaching of a complex nickel–iron concentrate by mesophile bacteria

Santos

Barbosa

Souza³

et al. 2006

Minerals Engineering

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“…In vitro oxidation experiments with Aznalcó llar sludge samples in a flow-through reactor showed that sphalerite dissolved faster than pyrite in the 2.5 to 4.7 pH range (Domè nech et al, 2002). This result can be partly attributed to a galvanic interaction between pyrite and sphalerite that is usually observed in sulfide mixtures Murr, 1983, 2004;Balá ž et al, 1994;Cruz et al, 2001Cruz et al, , 2005. Hita and Torrent (2005b) examined samples of the contaminated soils and concluded that: (i) weathering via oxidative dissolution of pyrite was fast, so 51 and 69% of this mineral had weathered by November 2000 and June 2001(that is, two and three rainy seasons after the spillage), respectively; (ii) sphalerite had weathered to approximately the same extent as pyrite; (iii) further weathering was unlikely to be significant because only the coarse, less reactive sludge particles remained in the soil; and (iv) a significant portion of the Zn released appeared to be occluded in Fe oxides resulting from the oxidation of pyrite.…”

mentioning

confidence: 96%

Experimental Oxidative Dissolution of Sphalerite in the Aznalcóllar Sludge and Other Pyritic Matrices

2006

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After the collapse on 25 Apr. 1998 of the Aznalcóllar mine tailings dike in southwestern Spain, 45 km2 of the Guadiamar valley were covered by a pyritic sludge containing up to 2% sphalerite (ZnS). Later, the sludge was mechanically removed and calcium carbonate was plowed into the soil to immobilize heavy metals. By June 2001 more than 60% of the sulfides in the residual sludge had oxidized and soil Zn contents reached locally phytotoxic levels. Therefore, the oxidative dissolution of sphalerite in the sludge and other pyritic samples was examined. Flow-through oxidation experiments showed that: (i) about 5 and 17% of the sludge Fe and Zn were in soluble form, respectively, because the sludge sample had been partly oxidized in the field; (ii) the oxidation rates of the residual pyrite and sphalerite were similar; (iii) the overall sulfide oxidation rate was relatively unaffected by the addition of calcite; and (iv) poorly crystalline Fe (hydr)oxides containing Zn in occluded form and Zn (hydroxi)carbonates were formed in the presence of calcite. The rate of oxidation of reference sphalerite greatly increased when it was incorporated in the sludge or in a reference pyrite matrix. This enhancement was due to galvanic interaction because pyrite oxidation was depressed in the presence of sphalerite. Oxidation by Fe3+ ions was less important because the oxidation rates of native sphalerite were not greater at low than at high pH. The fast oxidation rate of sphalerite in the Aznalcóllar sludge indicates a need for quick adoption of remediation measures in similar accidents elsewhere. The use of calcite amendments has little influence on the oxidation rate but does result in the accumulation of Zn in relatively insoluble forms.

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“…However, this order is subject to change when other factors such as galvanic interactions (Kwong et al, 2003;Cruz et al, 2005) and biological interactions (Kuyucak, 2002;Egiebor and Oni, 2007) are considered. On oxidation product layers may develop which can control the rate of diffusion and thus the overall rate of oxidation (pyrite and pyrrhotite, Blowes and Jambor, 1990;Lottermoser, 2010;galena, Garcia et al, 1995;Diehl et al, 2006;sphalerite, Weisner et al, 2003;arsenopyrite, Harvey et al, 2006;Murceigo et al, 2011).…”

Section: Acid Rock Drainage Formationmentioning

confidence: 99%