An electrochemical study of the surface oxidation of arsenopyrite in alkaline media

Sánchez, Víctor Hugo; Hiskey, J. B.

doi:10.1007/bf02651417

Cited by 18 publications

(15 citation statements)

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“…18,19. An electrode constructed with a massive crystal sample was used to compare the data obtained with others in literature 3,4,[8][9][10] and with that obtained from the ground mineral electrodes. A complete description of the electrode construction can be found in ref.…”

Section: Methodsmentioning

confidence: 99%

“…Like many other conducting and semiconducting solids, arsenopyrite undergoes dissolution by an electrochemical mechanism. [3][4][5][6][7][8][9][10] The treatment of arsenopyrite usually involves flotation processes and several studies found in literature are directed to the investigation of the mineral dissolution in alkaline media. [3][4][5][6] Arsenopyrite is also worthy of attention because it is abundant and difficult to leach.…”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5][6][7][8][9][10] The treatment of arsenopyrite usually involves flotation processes and several studies found in literature are directed to the investigation of the mineral dissolution in alkaline media. [3][4][5][6] Arsenopyrite is also worthy of attention because it is abundant and difficult to leach. Most of the works about electrochemical oxidation of arsenopyrite in acidic media have been performed at low pH (0.0-2.5) as the electrochemical oxidation pathway could be involved in the leaching and bioleaching processes.…”

Section: Introductionmentioning

confidence: 99%

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Electrochemical study of arsenopyrite weathering

Almeida

Giannetti

2002

Phys. Chem. Chem. Phys.

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Cyclic voltammograms and capacitance measurements are presented to characterize the mineral response at relatively moderate environmental conditions, pH 4.5 and T ¼ 25 C. The experiments involve examining the rates of oxidation and the surface morphology of arsenopyrite, which is oxidized abiotically. The semiconducting properties of the mineral have been investigated in attempt to gain additional information of FeAsS dissolution behavior in acidic solutions at potentials close to the open circuit potential of the mineral. A mechanistic pathway for the anodic dissolution of arsenopyrite in open circuit conditions is also suggested. At high overpotentials, anodic reactions produce mainly sulfate and arsenate ions and may be described as hole limited. The reduction of orpiment-like compounds at potentials more negative than the open circuit potential is discussed.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrochemical study of arsenopyrite weathering

Almeida

Giannetti

2002

Phys. Chem. Chem. Phys.

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“…Inicialmente, o potencial da arsenopirita aumentou, indicando uma rápida oxidação de sua superfície possivelmente de acordo com a reação. (7) FeAsS+9H 2 O=FeOOH+H 2 AsO 3 -+SO 4 2 + 15H + + 12e -A seguir, sofreu uma diminuição até se tornar constante a partir de 10 minutos. Quando o eletrodo de arsenopirita foi interligado ao de pirita, os valores de potencial decaíram nos 10 primeiros minutos, para em seguida, aumentarem até um patamar em torno de 140 mV, evidenciando uma oxidação causada pela interação com a pirita.…”

Section: Resultsunclassified

Estudo Eletroquímico Da Interação Galvânica Entre Pirita E Arsenopirita

Júnior¹,

Dutra²,

Monte³

2006

TMM

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A interação galvânica é a interação entre dois minerais causada pelas suas reatividades eletroquímicas. Ocorre quando os minerais (ou o mineral e o meio de moagem) estão em contato formando uma célula galvânica, que leva a reações de oxirredução devido às diferenças entre os potenciais de repouso dos minerais. A reatividade eletroquímica é indicada pelo potencial de repouso. Logo, na célula galvânica, o mineral com maior potencial de repouso atua como catodo e é considerado um mineral nobre. Já, o mineral com menor potencial de repouso comporta-se como anodo, sendo considerado um mineral mais ativo. A corrente galvânica que flui entre esses minerais está associada às alterações em suas superfícies. A presença de oxigênio dissolvido na solução tem importância fundamental para a interação galvânica, desde que o oxigênio atue como um aceptor de elétrons, reagindo para formar OH -nos minerais mais nobres. Modelos de interações galvânicas podem ser estabelecidos dependendo do número de componentes galvânicos no sistema. Todavia, para um sistema múltiplo mineral-meio de moagem, as interações galvânicas tornam-se mais complexas que para um sistema de dois eletrodos.No ResumoA interação galvânica promove reações de oxirredução devido às diferenças entre os potenciais de repouso dos minerais sulfetados, afetando suas flotabilidades. Por isso, foi iniciado um estudo sobre a interação pirita-arsenopirita sob diferentes condições de aeração. Foram tomadas medidas de potencial de eletrodos minerais com e sem interligação elétrica. Na ausência de interação, a pirita foi oxidada a Fe(OH) 3 . Ao se interligar o eletrodo de pirita ao de arsenopirita, a interação pirita-arsenopirita inibiu a oxidação da pirita. O potencial da arsenopirita aumentou, indicando a formação de FeOOH. Quando o eletrodo de arsenopirita foi interligado ao de pirita, os valores de seu potencial aumentaram, evidenciando uma oxidação. Quando nitrogênio foi borbulhado na solução, o potencial da arsenopirita, ao ser interligada à pirita, atingiu valores mais elevados, sugerindo que nessa interação a arsenopirita comporta-se anodicamente. Palavras-chave: Pirita; Arsenopirita; Interação galvânica; Oxidação. ELECTROCHEMICAL STUDY OF GALVANIC INTERACTION BETWEEN PYRITE AND ARSENOPYRITE AbstractGalvanic interaction leads to redox reactions, due to the sulfide minerals rest potentials difference, affecting their floatabilities. A study about the interaction between pyrite and arsenopyrite, under different aeration conditions was carried out. Rest potentials of mineral electrodes were measured with and without electrical contact. The pyrite electrode without contact with arsenopyrite has been oxidized to Fe(OH) 3 . When kept in contact with arsenopyrite, the interaction pyrite-arsenopyrite inhibited the oxidation of the pyrite. The potential of arsenopyrite increased, indicating the formation of FeOOH. When kept in contact with the pyrite electrode, the values of potential increased, making evident an oxidation. When nitrogen was bubbled in the solution, the potent...

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“…However, there is no agreement on which are the two steps. Sanchez and Hiskey [5] argue that the first step results in the formation of an iron hydroxide/oxide, SO…”

Section: Resultsmentioning

confidence: 99%

Acid Production from Mixed Sulfide Minerals: The Mixture Pyrite/Arsenopyrite

Almeida

Giannetti

2003

Port. Electrochim. Acta

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To evaluate the response of pyrite and arsenopyrite to oxidizing conditions, an electrochemical approach was employed, to set boundaries for the influence of the arsenopyrite content. The effects of galvanic interactions and local pH on the oxidation reaction of pyrite were also studied. With this purpose, artificial two-mineral electrodes were constructed ranging in concentration from 20-80% arsenopyrite. The resulting cyclic voltammograms were analyzed and relative quantities of oxidation products were evaluated.

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An electrochemical study of the surface oxidation of arsenopyrite in alkaline media

Cited by 18 publications

References 5 publications

Electrochemical study of arsenopyrite weathering

Electrochemical study of arsenopyrite weathering

Estudo Eletroquímico Da Interação Galvânica Entre Pirita E Arsenopirita

Acid Production from Mixed Sulfide Minerals: The Mixture Pyrite/Arsenopyrite

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