Mechanism of sulfur oxidation in pyrite

Chander, Subhash; Briceno, A.; Pang, J.

doi:10.1007/bf03403011

Cited by 4 publications

(3 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This reaction indicates there should be a surface layer, but a clear passive region cannot be identified in Figure 1. A possible explanation is that there is only a very narrow potential gap between the passive and trans-passive regions, so, according to Chander et al, 19…”

Section: Potentiodynamic Studymentioning

confidence: 99%

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H₂SO₄

Liu

Wang

Chen

et al. 2019

Journal of Chemical Research

View full text Add to dashboard Cite

Chalcopyrite is the most abundant, but also one of the most refractory, copper sources. One way to enhance chalcopyrite’s electrochemical dissolution is by mixing it with pyrite. To understand how and to what extent pyrite affects chalcopyrite’s electrochemical dissolution at different potentials, the electrochemical behaviors of chalcopyrite, pyrite, and chalcopyrite–pyrite couples in pH 1.8 H2SO4 were studied by potentiodynamic and electrochemical impedance spectroscopy. Potentiodynamic curves showed their different electrochemical reaction states and electrode surface characteristics. From open-circuit potential to 470 mV (vs saturated calomel electrode), chalcopyrite–pyrite was passivated with Cu1− xFe1− yS2 [Formula: see text]; from 470 to 580 mV, trans-passive dissolution occurred, and in the passive region, Cu1− xFe1− yS2 transformed into Cu1− x− zS2; from 580 to 700 mV was an active region; and a pseudo-passive region was formed with CuS when the potential was above 700 mV. The smaller charge transfer resistance and passive resistance, as well as the smaller inductive relaxation, revealed how and to what extent the coupled pyrite accelerated the electrochemical dissolution of chalcopyrite.

show abstract

Section: Potentiodynamic Studymentioning

confidence: 99%

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H₂SO₄

Liu

Wang

Chen

et al. 2019

Journal of Chemical Research

View full text Add to dashboard Cite

show abstract

“…For this purpose, various oxidizing agents, such as oxygen, hydrogen peroxide, ferric sulfate, ferric chloride, potassium permanganate, and perchloric and nitric acids, have been used to oxidize pyrite. 3,14-16 In general, at low pH, pyrite oxidation proceeds through two basic steps: 17,18 In the first step, the dissolution of pyrite to ferrous ions in an acid medium proceeds through the formation of an iron-deficient or a sulfur-rich layer rather than elemental sulfur.…”

Section: Introductionmentioning

confidence: 99%

Coal Desulfurization in Oxidative Acid Media Using Hydrogen Peroxide and Ozone: A Kinetic and Statistical Approach

Pedroza¹,

Sánchez²,

Aguilar³

et al. 2009

Energy Fuels

View full text Add to dashboard Cite

The removal of pyritic sulfur from a Mexican sub-bituminous coal in nitric, sulfuric, and hydrochloric acid solutions was investigated. The effect of the type and concentration of acid, in the presence of hydrogen peroxide and ozone as oxidants, in a temperature range of 20−60 °C, was studied. The relevant factors in pyrite dissolution were determined by means of the statistical analysis of variance and optimized by the response surface method. Kinetic models were also evaluated, showing that the dissolution of pyritic sulfur follows the kinetic model of the shrinking core model, with diffusion through the solid product of the reaction as the controlling stage. The results of statistical analysis indicate that the use of ozone as an oxidant improves the pyrite dissolution because, at 0.25 M HNO3 or H2SO4 at 20 °C and 0.33 g/h O3, the obtained dissolution is similar to that of 1 M H2O2 and 1 M HNO3 or H2SO4 at 40 °C.

show abstract

“…Mechanisms of pyrite oxidation have been studied extensively and reviewed thoroughly (Hamilton and Woods 1981, Buckley and Woods 1987, Moses et al 1987, Moses and Herman 1991, Chander et al 1993, Chernyshova 2003, Rimstidt and Vaughan 2003, Evangelou and Zhang 2009, Chandra and Gerson 2010, Chiriţă et al 2014). Hamilton et al (Hamilton and Woods 1981) investigated pyrite surface oxidation mechanism using cyclic voltammetry coupled with Eh-pH diagrams.…”

Section: Significance Of Oxidation Of Pyrite On Flotationmentioning

confidence: 99%

The influence of mineralogy and surface chemistry on flotation of Cortez complex carbonaceous double refractory gold ore

Thella¹

View full text Add to dashboard Cite

The recovery of gold from complex refractory gold ores is challenging. The refractory nature of these ores is due to the encapsulation of gold as colloidal gold particles or as gold in solid solution in a mineral matrix which is unreactive and impervious during the cyanide leaching process. The complexity of processing increases when both the presence of disseminated gold in the mineral matrix as well as the interference phases are present in the ore. The ore investigated in this research, from Barrick's Cortez mine in Nevada, USA, is a notable example of this type of complex refractory ore which is described as double-refractory due to the presence of gold in a sulfide mineral matrix as well as in carbonaceous matter in the ore. Double-refractory ores give low recoveries of gold during the cyanide leaching process, and a pre-concentration stage is required to achieve acceptable gold recoveries. Typically, flotation is the pre-concentration method employed to recover the gold-bearing mineral phases in the ore. Although the flotation response of Cortez double refractory gold ore has been assessed at a number of commercial laboratories, gold recoveries remain lower than expected, and the reasons for this are not well understood. This thesis examines the influence of mineralogy and surface chemistry on the flotation recovery of gold in the Cortez double refractory gold ore. A comprehensive, novel experimental approach that combines solution analysis, optical microscopy, SEM-based automated mineral analysis (MLA/QEMSCAN), Raman spectroscopy, Dynamic secondary ion mass spectrometry, ToF-SIMS and X-ray photoelectron spectroscopy analysis on flotation feed, concentrates (both carbonaceous matter (TCM) and sulfides concentrates) and tailings has been applied to identify the causes of low gold recovery in flotation. The results of the research have shown that contrary to the expected deportment of gold in Carlin-type deposits as invisible gold associated with sulfide minerals, the gold in this Cortez ore is predominantly visible gold, present as native gold grains ranging in size from 2 to 33 µm with an average of 10µm. This is the main cause of the low gold recovery observed for this ore when treated with the standard Cortez ore flotation reagent regime which is designed to recover gold-bearing pyrite. The xanthate collector used in the standard Cortez reagent regime would not selectively recover grains of native gold. Exploratory flotation tests with a collector that specifically targets viii Financial support This research work was fully funded by Barrick Gold Corporation, Canada and I take immense pleasure in thanking Barrick personnel especially Dr. Barun Gorain who made my Ph.D. experience productive and fruitful.

show abstract

Mechanism of sulfur oxidation in pyrite

Cited by 4 publications

References 10 publications

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H₂SO₄

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H₂SO₄

Coal Desulfurization in Oxidative Acid Media Using Hydrogen Peroxide and Ozone: A Kinetic and Statistical Approach

The influence of mineralogy and surface chemistry on flotation of Cortez complex carbonaceous double refractory gold ore

Contact Info

Product

Resources

About

Mechanism of sulfur oxidation in pyrite

Cited by 4 publications

References 10 publications

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H2SO4

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H2SO4

Coal Desulfurization in Oxidative Acid Media Using Hydrogen Peroxide and Ozone: A Kinetic and Statistical Approach

The influence of mineralogy and surface chemistry on flotation of Cortez complex carbonaceous double refractory gold ore

Contact Info

Product

Resources

About

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H₂SO₄

Effect of pyrite on the electrochemical behavior of chalcopyrite at different potentials in pH 1.8 H₂SO₄