Electrochemical sulfur removal from chalcopyrite in molten NaCl-KCl

Mingsheng Tan; Rui He; Yating Yuan; Zhiyong Wang; Xianbo Jin

doi:10.1016/j.electacta.2016.07.088

Electrochemical sulfur removal from chalcopyrite in molten NaCl-KCl

Mingsheng Tan, Rui He, Yating Yuan, Zhiyong Wang, Xianbo Jin

Research output: Contribution to journal › Article › peer-review

37 Scopus citations

Abstract

Electrolysis of solid chalcopyrite (CuFeS₂) against a graphite inert anode has been studied in equimolar NaCl-KCl melt at 700 °C. During electrolysis, S²⁻ ions are released from the solid CuFeS₂ cathode, transfer to the graphite anode and discharge to S₂ gas. The reduction mechanism of CuFeS₂ was investigated by cyclic voltammetry, potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction contains mainly three stages: the insertion of Na⁺ or K⁺ into CuFeS₂, forming L_xCuFeS₂ (L = Na or K, x ≤ 1); the partial reduction of L_xCuFeS₂ to L_x-wCuFe_1-yS_2-z and Fe; the complete reduction to a mixture of Cu and Fe, which can be magnetically separated. After the separation, pure Cu can be obtained by leaching out the residual Fe with acid. Electrolysis at a cell voltage of 2.4 V has led to a rapid reduction of CuFeS₂. The current efficiency and energy consumption were 85% and 1.68 kWh/kg-CuFeS₂, respectively.

Original language	English
Pages (from-to)	148-154
Number of pages	7
Journal	Electrochimica Acta
Volume	213
DOIs	https://doi.org/10.1016/j.electacta.2016.07.088
State	Published - Sep 20 2016
Externally published	Yes

Keywords

chalcopyrite metallurgy
copper
metal sulfides
molten salts
solid state electrolysis

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10.1016/j.electacta.2016.07.088

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title = "Electrochemical sulfur removal from chalcopyrite in molten NaCl-KCl",

abstract = "Electrolysis of solid chalcopyrite (CuFeS2) against a graphite inert anode has been studied in equimolar NaCl-KCl melt at 700 °C. During electrolysis, S2− ions are released from the solid CuFeS2 cathode, transfer to the graphite anode and discharge to S2 gas. The reduction mechanism of CuFeS2 was investigated by cyclic voltammetry, potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction contains mainly three stages: the insertion of Na+ or K+ into CuFeS2, forming LxCuFeS2 (L = Na or K, x ≤ 1); the partial reduction of LxCuFeS2 to Lx-wCuFe1-yS2-z and Fe; the complete reduction to a mixture of Cu and Fe, which can be magnetically separated. After the separation, pure Cu can be obtained by leaching out the residual Fe with acid. Electrolysis at a cell voltage of 2.4 V has led to a rapid reduction of CuFeS2. The current efficiency and energy consumption were 85% and 1.68 kWh/kg-CuFeS2, respectively.",

keywords = "chalcopyrite metallurgy, copper, metal sulfides, molten salts, solid state electrolysis",

author = "Mingsheng Tan and Rui He and Yating Yuan and Zhiyong Wang and Xianbo Jin",

note = "Publisher Copyright: {\textcopyright} 2016 Elsevier Ltd",

year = "2016",

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doi = "10.1016/j.electacta.2016.07.088",

language = "English",

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T1 - Electrochemical sulfur removal from chalcopyrite in molten NaCl-KCl

AU - Tan, Mingsheng

AU - He, Rui

AU - Yuan, Yating

AU - Wang, Zhiyong

AU - Jin, Xianbo

PY - 2016/9/20

Y1 - 2016/9/20

N2 - Electrolysis of solid chalcopyrite (CuFeS2) against a graphite inert anode has been studied in equimolar NaCl-KCl melt at 700 °C. During electrolysis, S2− ions are released from the solid CuFeS2 cathode, transfer to the graphite anode and discharge to S2 gas. The reduction mechanism of CuFeS2 was investigated by cyclic voltammetry, potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction contains mainly three stages: the insertion of Na+ or K+ into CuFeS2, forming LxCuFeS2 (L = Na or K, x ≤ 1); the partial reduction of LxCuFeS2 to Lx-wCuFe1-yS2-z and Fe; the complete reduction to a mixture of Cu and Fe, which can be magnetically separated. After the separation, pure Cu can be obtained by leaching out the residual Fe with acid. Electrolysis at a cell voltage of 2.4 V has led to a rapid reduction of CuFeS2. The current efficiency and energy consumption were 85% and 1.68 kWh/kg-CuFeS2, respectively.

AB - Electrolysis of solid chalcopyrite (CuFeS2) against a graphite inert anode has been studied in equimolar NaCl-KCl melt at 700 °C. During electrolysis, S2− ions are released from the solid CuFeS2 cathode, transfer to the graphite anode and discharge to S2 gas. The reduction mechanism of CuFeS2 was investigated by cyclic voltammetry, potentiostatic and constant voltage electrolysis together with spectroscopic and scanning electron microscopic analyses. The reduction contains mainly three stages: the insertion of Na+ or K+ into CuFeS2, forming LxCuFeS2 (L = Na or K, x ≤ 1); the partial reduction of LxCuFeS2 to Lx-wCuFe1-yS2-z and Fe; the complete reduction to a mixture of Cu and Fe, which can be magnetically separated. After the separation, pure Cu can be obtained by leaching out the residual Fe with acid. Electrolysis at a cell voltage of 2.4 V has led to a rapid reduction of CuFeS2. The current efficiency and energy consumption were 85% and 1.68 kWh/kg-CuFeS2, respectively.

KW - chalcopyrite metallurgy

KW - copper

KW - metal sulfides

KW - molten salts

KW - solid state electrolysis

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U2 - 10.1016/j.electacta.2016.07.088

DO - 10.1016/j.electacta.2016.07.088

M3 - Article

AN - SCOPUS:84979025668

SN - 0013-4686

VL - 213

SP - 148

EP - 154

JO - Electrochimica Acta

JF - Electrochimica Acta

ER -

Electrochemical sulfur removal from chalcopyrite in molten NaCl-KCl

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