Anodic behaviour of lead sulphide in hydrochloric acid

Ghali, Edward; Dandapani, B.

doi:10.1007/bf00617208

Cited by 17 publications

(3 citation statements)

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“…2 The physicochemical surface properties of sulfide minerals are also important for hydrometallurgical operations such as leaching performed under acidic and oxidizing conditions. [3][4][5][6][7][8] In this case, the formation of oxidation products, such as elemental sulfur, will influence the rate of dissolution of metal ions into solution. The nucleation, growth, and overlap of oxidation products can result in a passivating layer, which obstructs the reacting sulfide mineral surface and hinders dissolution.…”

Section: Introductionmentioning

confidence: 99%

Physical and Chemical Analysis of Elemental Sulfur Formation during Galena Surface Oxidation

2011

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The surface oxidation of sulfide minerals, such as galena (PbS), in aqueous solutions is of critical importance in a number of applications. A comprehensive understanding of the formation of oxidation species at the galena surface is still lacking. Much controversy over the nature of these oxidation products exists. A number of oxidation pathways have been proposed, and experimental evidence for the formation of elemental sulfur, metal polysulfides, and metal-deficient lead sulfides in acidic conditions has been shown and argued. This paper provides further insight into the electrochemical behavior of galena at pH 4.5. Utilizing a novel experimental system that combines in situ electrochemical control and AC mode atomic force microscopy (AFM) surface imaging, the formation and growth of nanoscopic domains on the galena surface are detected and examined at anodic potentials. AFM phase images indicate that these domains have different material properties to the underlying galena. Continued oxidation results in nanoscopic pitting and the formation of microscopic surface domains, which are confirmed to be elemental sulfur by Raman spectroscopy. Further clarification of the presence of elemental sulfur is provided by Cryo-XPS. Polysulfide and metal-deficient sulfide could not be detected within this system.

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Section: Introductionmentioning

confidence: 99%

Physical and Chemical Analysis of Elemental Sulfur Formation during Galena Surface Oxidation

2011

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“…The choice of the acidified ammonium acetate bath was based on previous studies carried out in our laboratory (12)(13)(14) to investigate the dissolution of galena in different media. The results showed that the anodic passivation caused mainly by lead chloride formation is reduced in acetate medium due to the strong activity of ammonium acetate in dissolving PbC12.…”

Section: Introductionmentioning

confidence: 99%

“…Considerable difficulties arise in the electrochemical studies of metal deposition due to the complex structure of the underlying metal (6) which lead to poor reproducibility, particularly in the appearance and structure of the deposits (7). There have been several studies of electrodeposition of lead (8-1 1).The choice of the acidified ammonium acetate bath was based on previous studies carried out in our laboratory (12)(13)(14) to investigate the dissolution of galena in different media. The results showed that the anodic passivation caused mainly by lead chloride formation is reduced in acetate medium due to the strong activity of ammonium acetate in dissolving PbC12.…”

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Effect of temperature on cyclic voltammograms during the electrodeposition of lead

Girgis¹,

Ghali²

1989

Can. J. Chem.

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MAGDY GIRGIS and EDWARD GHALI. Can. J. Chem. 67, 130 (1989). The electrochemical behavior of lead deposition process in a temperature range between 25 and 75°C was studied in a medium of lead chloride and ammonium acetate by linear and cyclic sweep perturbation. The study was undertaken on four substrates: Pb, Cu, Ag, and C. An increase in temperature resulted in accelerating the deposition process and promoted dendrite formation. Moreover, different kinetic parameters such as adsorption isotherms, Tafel slopes, and diffusion coefficient were affected as a function of temperature elevation. Surface analytical study performed by Auger electron spectroscopy revealed an increase in peak intensities of C1 and Pb as the temperature increased.Key words: electrodeposition, cyclic voltammetry, potentiostatic transients, underpotential deposition, temperature effect. IntroductionThe use of stationary electrode voltammetry in qualitative and quantitative investigations of electrolysis mechanisms has been extensive (1 -3), particularly in the field of electrocrystallization (4, 5). Considerable difficulties arise in the electrochemical studies of metal deposition due to the complex structure of the underlying metal (6) which lead to poor reproducibility, particularly in the appearance and structure of the deposits (7). There have been several studies of electrodeposition of lead (8-1 1).The choice of the acidified ammonium acetate bath was based on previous studies carried out in our laboratory (12)(13)(14) to investigate the dissolution of galena in different media. The results showed that the anodic passivation caused mainly by lead chloride formation is reduced in acetate medium due to the strong activity of ammonium acetate in dissolving PbC12.In the frame work of this approach, other studies (15, 16) have been undertaken to study lead deposition process from these media in order to find the optimum conditions necessary to obtain the metal directly from the sulphide ore. The investigation of this system at ambient temperature was carried out using different electrochemical techniques ( 17). To obtain more information about the cathodic process we tried to study the effect of elevated temperature on the system. To our knowledge, the effect of temperature on the behaviour of lead ions during the deposition process has not been reported in literature. This paper, therefore, has been intended to shed some light on the reaction mechanism during the deposition process in acetate medium as a function of temperature by employing the techni-

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Concentration effects of hydrochloric acid on the anodic behaviour of lead sulphide

Dandapani

Ghali

1982

J Appl Electrochem

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Anodic behaviour of lead sulphide in hydrochloric acid

Cited by 17 publications

References 3 publications

Physical and Chemical Analysis of Elemental Sulfur Formation during Galena Surface Oxidation

Physical and Chemical Analysis of Elemental Sulfur Formation during Galena Surface Oxidation

Effect of temperature on cyclic voltammograms during the electrodeposition of lead

Concentration effects of hydrochloric acid on the anodic behaviour of lead sulphide

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