Oxidation states and speciation of secondary products on pyrite and arsenopyrite reacted with mine waste waters and air

Nesbitt, H.W.; Muir, I.J.

doi:10.1007/bf01173766

Cited by 181 publications

(108 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[38,46,48,50,51]. It should be noted that the hydroxide and sulfate were fitted at 531.3 ± 0.1 eV due to overlapping of the binding energy of these two O species [52]. The presence of oxide on chalcopyrite surface was consistent with the S 2p analysis discussed above.…”

Section: S 2p Spectrasupporting

confidence: 71%

The Influencing Mechanisms of Sodium Hexametaphosphate on Chalcopyrite Flotation in the Presence of MgCl2 and CaCl2

Xiao

et al. 2018

Minerals

View full text Add to dashboard Cite

Sea water has been used in flotation plants, showing a promising way to save fresh water usage. Previous studies indicated that divalent salts in sea water played negative roles in chalcopyrite flotation, but not much work have been conducted to understand the eliminating mechanisms. This study systematically investigated the effects of divalent cations of Ca 2+ and Mg 2+ on natural flotability of chalcopyrite in the absence of collectors and frothers. The reduced recovery was mainly due to the adsorption of Mg and Ca hydroxyl complexes and precipitation on chalcopyrite surfaces, giving rise to a less hydrophobic surface. The addition of sodium hexametaphosphate (SHMP), however, significantly improved chalcopyrite recovery. Species calculation, contact angle, zeta potential, FTIR and XPS analyses were conducted to understand the influencing mechanisms of divalent ions and the beneficial effects of SHMP on chalcopyrite recovery. The primary mechanism was that SHMP prevented the adsorption of positively charged Mg and Ca compounds or precipitation with hydrophilic properties such as Mg(OH) 2 on chalcopyrite surfaces, confirmed by the Derjguin-Landau-Verwey-Overbeek (DLVO) theory. Secondly, SHMP reacted with Mg 2+ and Ca 2+ to form dissolvable complexes, thereby declining the formation of insoluble Mg 2+ and Ca 2+ compounds or precipitation.

show abstract

Section: S 2p Spectrasupporting

confidence: 71%

The Influencing Mechanisms of Sodium Hexametaphosphate on Chalcopyrite Flotation in the Presence of MgCl2 and CaCl2

Xiao

et al. 2018

Minerals

View full text Add to dashboard Cite

show abstract

“…The binding energy of Fe(III)-S is generally accepted to be 707-708 eV while 711-712 eV is indicative of Fe(III)-O/OH [74][75][76]. Li, et al [20] reported that synchrotron XPS Fe 2p spectra collected from a freshly fractured chalcopyrite surface showed a strong peak around 708 eV arising from fully coordinated Fe(III) bonded to S in the bulk chalcopyrite, in accord with other literature reports [5,36,[77][78][79][80].…”

Section: Xps Analyses For 1 and 30 H Leach Residues From Ph 1 Lixiviantsupporting

confidence: 61%

Kinetics and Mechanisms of Chalcopyrite Dissolution at Controlled Redox Potential of 750 mV in Sulfuric Acid Solution

Wei

Qian

et al. 2016

Minerals

View full text Add to dashboard Cite

Abstract:To better understand chalcopyrite leach mechanisms and kinetics, for improved Cu extraction during hydrometallurgical processing, chalcopyrite leaching has been conducted at solution redox potential 750 mV, 35-75˝C, and pH 1.0 with and without aqueous iron addition, and pH 1.5 and 2.0 without aqueous iron addition. The activation energy (E a ) values derived indicate chalcopyrite dissolution is initially surface chemical reaction controlled, which is associated with the activities of Fe 3+ and H + with reaction orders of 0.12 and´0.28, respectively. A surface diffusion controlled mechanism is proposed for the later leaching stage with correspondingly low E a values. Surface analyses indicate surface products (predominantly S n 2´a nd S 0 ) did not inhibit chalcopyrite dissolution, consistent with the increased surface area normalised leach rate during the later stage. The addition of aqueous iron plays an important role in accelerating Cu leaching rates, especially at lower temperature, primarily by reducing the length of time of the initial surface chemical reaction controlled stage.

show abstract

“…None of the wells near the cores have conditions for sulfide equilibrium, but arsenopyrite is often observed out of equilibrium with its environment, and this disequilibrium persistence has been attributed to rinds of oxides forming on the outside of arsenopyrite grains in sediments and in lab-based oxidation experiments (Richardson and Vaughan, 1989;Craw et al, 2003). However, long-term experiments on mine wastes have shown that poorly crystalline Fe(III)(oxyhydr)oxide rinds are very effective at passivating the surface of arsenopyrite in air, but in aqueous solutions the rinds permit extensive leaching of As from the mineral grain into solution (Nesbitt and Muir, 1998).…”

Section: Geochemical Disequilibrium In Glacial Aquifersmentioning

confidence: 99%

Solid-phase arsenic speciation in aquifer sediments: A micro-X-ray absorption spectroscopy approach for quantifying trace-level speciation

Nicholas

Erickson

Woodruff

et al. 2017

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Arsenic (As) is a geogenic contaminant affecting groundwater in geologically diverse systems globally. Arsenic release from aquifer sediments to groundwater is favored when biogeochemical conditions, especially oxidation-reduction (redox) potential, in aquifers fluctuate. The specific objective of this research is to identify the solid-phase sources and geochemical mechanisms of release of As in aquifers of the Des Moines Lobe glacial advance. The overarching concept is that conditions present at the aquifer-aquitard interfaces promote a suite of geochemical reactions leading to mineral alteration and release of As to groundwater. A microprobe X-ray absorption spectroscopy (lXAS) approach is developed and applied to rotosonic drill core samples to identify the solid-phase speciation of As in aquifer, aquitard, and aquifer-aquitard interface sediments. This approach addresses the low solid-phase As concentrations, as well as the fine-scale physical and chemical heterogeneity of the sediments. The spectroscopy data are analyzed using novel cosine-distance and correlation-distance hierarchical clustering for Fe 1s and As 1s lXAS datasets. The solid-phase Fe and As speciation is then interpreted using sediment and well-water chemical data to propose solid-phase As reservoirs and release mechanisms. The results confirm that in two of the three locations studied, the glacial sediment forming the aquitard is the source of As to the aquifer sediments. The results are consistent with three different As release mechanisms: (1) desorption from Fe (oxyhydr)oxides, (2) reductive dissolution of Fe (oxyhydr) oxides, and (3) oxidative dissolution of Fe sulfides. The findings confirm that glacial sediments at the interface between aquifer and aquitard are geochemically active zones for As. The diversity of As release mechanisms is consistent with the geographic heterogeneity observed in the distribution of elevated-As wells.

show abstract

Oxidation states and speciation of secondary products on pyrite and arsenopyrite reacted with mine waste waters and air

Cited by 181 publications

References 22 publications

The Influencing Mechanisms of Sodium Hexametaphosphate on Chalcopyrite Flotation in the Presence of MgCl2 and CaCl2

The Influencing Mechanisms of Sodium Hexametaphosphate on Chalcopyrite Flotation in the Presence of MgCl2 and CaCl2

Kinetics and Mechanisms of Chalcopyrite Dissolution at Controlled Redox Potential of 750 mV in Sulfuric Acid Solution

Solid-phase arsenic speciation in aquifer sediments: A micro-X-ray absorption spectroscopy approach for quantifying trace-level speciation

Contact Info

Product

Resources

About