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2 edition of Mechanism for anodic dissolution of chalcocite in cupric chloride solution found in the catalog.

Mechanism for anodic dissolution of chalcocite in cupric chloride solution

Srinivasan Venkatesh

Mechanism for anodic dissolution of chalcocite in cupric chloride solution

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  • 28 Currently reading

Published .
Written in English

    Subjects:
  • Chalcocite.,
  • Copper -- Oxidation.,
  • Metals -- Anodic oxidation.

  • Edition Notes

    Statementby Srinivasan Venkatesh.
    The Physical Object
    Paginationx, 109 leaves, bound :
    Number of Pages109
    ID Numbers
    Open LibraryOL16862256M


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Mechanism for anodic dissolution of chalcocite in cupric chloride solution by Srinivasan Venkatesh Download PDF EPUB FB2

Mechanism of anodic dissolution of chalcocite in hydrochloric acid solutionCited by: 3. The positive-going branch of the anodic voltammograms for chalcopyrite in dilute HCl solutions in the potential range appropriate to dissolution are shown in Fig.

low concentrations, two (perhaps three) peaks are apparent at about V and V ( V) that merge into a single peak in the solution of 1 M by:   In the most recent study (Miki et al., ), the effect of controlled solution potential on the rate of dissolution of synthetic covellite, chalcocite and digenite was studied in chloride solutions containing copper(II) and iron(III) ions under ambient conditions.

The results showed that the rate of dissolution of covellite is similar at Cited by: investigation of chalcopyrite (CuFeS2) dissolution in cupric chloride solutions. Firstly, the formation and composition of reaction product layers formed on chalcopyrite were studied.

Secondly, the rate-controlling step in chalcopyrite dissolution was defined and thirdly, the prevailing cupric and cuprous species were observed. Chemistry of chloride solutions 29 Thermodynamics of chalcopyrite oxidation in chloride solutions 34 Kinetics of the dissolution of chalcopyrite 41 Temperature 51 Particle size 52 The effect of additives 53 Effect of potential 63 Mechanism of the dissolution of chalcopyrite in chloride.

In the present work, an electrochemical study of the dissolution behaviour of chalcopyrite, the most common copper mineral, was made in a concentrated sodium chloride solution ( g/l) with. Comparison of chalcocite dissolution Fig SEM view ( X) of a partially leached (chloride system) particle Fig SEM view (1, X) of the layered structure developed during formation of blue-remaining covellite The first stage rate law for chalcocite dissolution in the chloride system is given by: Rate = k2AI[CI']I (10) which shows.

Chalcocite Cu2S c Mineral Data Publishing, version 1 Crystal Data: Monoclinic, pseudo-orthorhombic. Point Group: 2/m or m. Crystals are short prismatic [], thick to tabular {}, to 12 cm across, and prismatic [], to 25 cm long.

S.B. Lyon, in Shreir's Corrosion, Anion adsorption effects on the mechanism of dissolution. As key steps in the anodic dissolution mechanism for iron involve the adsorption of water or hydroxyl ions, it is evident that the presence of other anions that compete for adsorption will influence the concentration of the adsorbed hydroxyl intermediate and, in consequence, the.

Anodic dissolution assisted cracking is characteristically an intergranular mode of failure [1, 8, 20, 29].According to electrochemical theory anodic dissolution assisted cracking requires a condition that makes the grain boundaries or adjacent regions Mechanism for anodic dissolution of chalcocite in cupric chloride solution book to the rest of the microstructure, so that the dissolution proceeds selectively along the boundaries.

Abstract. One of the most important outstanding problems with the hydrometallurgy of copper is the low temperature leaching of chalcopyrite. In this thesis, a fundamental study at low temperature was undertaken in order to establish a mechanism, which is consistent with the data obtained in an extensive study of the kinetics of dissolution of several chalcopyrite concentrates.\ud \ud It will.

The anodic dissolution mechanism of copper in neutral aqueous solutions containing CO 3 2-and Cl-ions has been studied by channel flow electrode method.

The two consecutive Tafel regions appear on the anodic polarization curve in the potential range of. In a strong chloride solution the predominant cuprous, cupric, ferrous, and ferric chloride complexes are CuCl3 −2, CuCl+, CuCl2, FeCl2, and FeCl2 + respectively.

The probable dissolution reaction for chalcopyrite in cupric chloride solution is CuFeS2 + 3CuCl+ + 11Cl−2 = 4CuCl3 −2 + FeCl2 + 2S The standard free energy change for this reaction at 25°C and unit activities. The stoichiometry of anodic dissolution in both sulfate and chloride solutions at high potentials has confirmed published data of a consistent value of – F/mol copper dissolved that is independent of the source of the mineral, potential and solution composition.

measured in cupric chloride solution (F igure 1), b oth platinum and glassy carbon can be consid ered as suitable electrode materials for the study of cathodic reactions in cupric chloride solutions.

In the present paper, the influences of chloride and sulfate ions in natural aqueous solution on the anodic dissolution of copper have been investigated by using the electrochemical techniques. The anodic dissolution mechanisms of copper were proposed by determining the reaction parameters by the anodic polarization curves.

The region II has a slope of mV/decade in the potential range from to V and the current in this region depended on concentration of chloride ion (∂log i/∂log [Cl-]=1). Active dissolution mechanism of copper in weak alkaline carbonate solution containing chloride ion was proposed on the basis of these results.

Chloride solutions have become of great interest, having high leaching kinetics and no passivation of sulfide minerals. This thesis presents an investigation of chalcopyrite (CuFeS2) dissolution in cupric chloride solutions.

Firstly, the formation and composition of reaction product layers formed on chalcopyrite were studied. This paper summarizes the results of a voltammetric study of the anodic characteristics of chalcopyrite in the potential region relevant to heap leaching in concentrated chloride solutions.

Distinct peaks in the potential region of to V have been observed in the voltammograms, the magnitude of which depend on the chloride concentration and, particularly, the pH in the range 1 to 3.

The rate of anodic dissolution of pyrite in chloride solutions is independent of the acid and chloride concentration except at high chloride concentrations when the rate decreases slightly. In cupric chloride leaching, Cu+ forms very strong complexes with chloride ions, increasing Cu 2+ activity.

In addition, the redox potential of Cu 2+ /Cu+ is greater than that of Fe 3+ /Fe 2+ in concentrated chloride solutions. This makes the dissolution more beneficial in cupric chloride solutions compared to ferric chloride solutions [43,44,45].

The electrochemical behavior and electrodeposition of Sn were investigated in choline chloride (ChCl)–urea deep eutectic solvents (DESs) containing SnCl2 by cyclic voltammetry (CV) and chronoamperometry techniques. The electrodeposition of Sn(II) was a quasi-reversible, single-step two-electron-transfer process.

The average transfer coefficient and diffusion coefficient of M Sn(II) in. Fe-Cr alloys form a solid solution over a wide Cr content and anodic dissolution of these all oys is found "For correspondence: (E-mail: [email protected]) to be unifonn4.

An alloy containing> 12% chromium exhibited the behaviour of chromium electrode in. Chalcocite, copper(I) sulfide (Cu 2 S), is an important copper ore mineral. It has been mined for centuries and is one of the most profitable copper ores.

The reasons for this is its high copper content (67% atomic ratio and nearly 80% by weight) and the ease at which copper can be separated from sulfur. Investigation of the Anodic Dissolution of Zinc in Sodium Chloride Electrolyte – A Green Process 25 | Page chloride system [45], in potassium nitrate solution [46], in aqueous salt solutions such as Cl−, Br −, I, Ac−, SO 4 2− −and NO.

Copper(II), rather than oxygen, was found to be the primary oxidant on the mineral surface. Rapid formation of an iron oxide layer on the electrode surface was observed, which did not inhibit but slowed down the rate of anodic dissolution over time.

No iron was found in solution, whereas no copper was found in the surface layer. The anodic dissolution of zinc electrodes in sodium chloride aqueous solution has been investigated experimentally. The effects of application of polarity reversal (PR), ultrasonic (US) enhancement, stirring, current density (CD), concentration and pH of the supporting electrolyte, and.

This paper summarises the results of the first part of an electrochemical study of the anodic characteristics of chalcopyrite in the potential region relevant to ambient temperature heap leaching in chloride solutions during which both iron(II) and copper(II) act as oxidants for the mineral.

Mixed potential (Em) measurements in concentrated chloride solutions in the presence of iron(II) or. powdered chalcocite in air.

They found that both cupric sulfate and ferrous sul­ fate were formed slowly at about C. Ferrous sulfate reached its maximum form­ ation at 0 C; at C, its rate of formation equaled its rate of decomposi­ tion. Cupric sulfate reached its maximum formation at C. Above C, it. The mechanisms were uncovered using various surface characterization techniques, including SEM-EDX and XPS.

The thermodynamic calculation determined the speciation of iron and copper at increasing chloride concentration up to 3 M, based on which the actual cathodic and anodic reactions responsible for copper extraction were proposed. Extraction of copper from sufidic ores, either by pyrometallurgy or hydrometallurgy, has various limitations.

In this study, a solvometallurgical process for the extraction of copper from sulfidic ore minerals (chalcopyrite, bornite, chalcocite and digenite) was developed by using an organic lixiviant (FeCl 3 as oxidizing agent and ethylene glycol (EG) as organic solvent).

from to increased the copper ion concentration from to g/L. The results were in accordance with those by VILCÁEZ et al [4]. Chalcopyrite dissolution rate increases with the decrease of the initial pH for the dissolution of chalcopyrite in chemical leaching, which could be.

A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below mV (vs. SHE) to cause dissolution of the copper sulphide.

It was investigated that the kinetic parameters on the anodic dissolution mechanism of zinc in chloride solution with the measurement of anodic polarization. The following results were found. (1) The reaction rate of zinc anodic dissolution is proportional to the third order against the concentration of Cl - ion and to the zero order against.

The formation of a Cu2O precipitate induced via anodic copper dissolution in an aqueous sodium chloride electrolyte was studied over the pH range 1–7 by means of laser illumination and digital processing of video images.

A mechanism of precipitation is proposed on the basis of the experimental findings and the theory of ionic equilibria. A heap leaching method to recover copper from a primary copper sulphide mineral wherein the mineral is leached in an acidic chloride or mixed chloride/sulphate solution in the presence of oxygen with the surface potential of the mineral below mV (vs.

SHE) to cause dissolution of the copper sulphide. Copper(II), rather than oxygen, was found to be the primary oxidant on the mineral surface. Rapid formation of an iron oxide layer on the electrode surface was observed, which did not inhibit, but slowed down, the rate of anodic dissolution over time.

No iron was found in solution, whereas no copper was found in the surface layer. In the typical cupric chloride leaching system for gold, cupric ion concentration is between 1 and 40 g/L, redox potential for the couple [CuCl] + /[CuCl 3] 2− is between and mV vs.

Ag/AgCl and pH, typically kept at lower than 3. Gold dissolution rate increases at elevated temperature (65–95 °C) and with increasing cupric chloride concentration [].

Thus, another goal of this investigation is to compare the dissolution of copper in the chloride-rich ionic liquids with dissolution in aqueous chloride solutions. In this presentation, we will describe a kinetic analysis of the anodic dissolution of copper in the Lewis acidic and basic compositions of the AlCl 3 -EtMeImCl ionic liquid.

Chalcopyrite (CuFeS 2), a sulphidic copper mineral, is the primary sources of copper. The direct production of copper sulphate from sulphidic copper ores is an important route to recover copper.

The conditions, however, are dependent on temperature and sulphatising environment and then dissolution. An electrochemical study was conducted on a stationary, synthetically produced, covellite electrode in acidic, chloride solutions at ambient conditions to investigate the dissolution behaviour of the mineral over a surface potential range from the open circuit potential (OCP) to about V (vs.

SHE).The dissolution of chalcocite in oxygenated sulfuric acid solution, ([New Mexico. Bureau of Mines and Mineral Resources]) Unknown Binding – January 1, by Walter W Fisher (Author) See all formats and editions Hide other formats and editions.

The Amazon Book Review Book recommendations, author interviews, editors' picks, and more. Author: Walter W Fisher.Vereecken, J. and Winand, R., “Influence of Poly-acrylamides on the Quality of Copper Deposits from Acidic Copper Sulfate Solutions,” Surface Technology, Vol.

4.