Electrochemical Properties and Microstructure of Al/Pb–Agand Al/Pb–Ag–Co Anodes for Zinc Electrowinning

Yongchun Zhang • Buming Chen • Zhongcheng Guo

Received: 21 September 2013 / Revised: 8 November 2013 / Published online: 19 April 2014

� The Chinese Society for Metals and Springer-Verlag Berlin Heidelberg 2014

Abstract The Al/Pb–0.8%Ag and Al/Pb–0.75%Ag–0.03%Co (in mass fraction) anodes used in zinc electrowinning are

prepared through the electrodeposition of lead methanesulfonate electrolyte onto an aluminum matrix. The results of anode

polarization curves, Tafel curves, and EIS characterizations indicated that the Al/Pb–0.75%Ag–0.03%Co anode has higher

electrocatalytic activity and corrosion resistance than the Al/Pb–0.8%Ag anode. SEM observations on the fruit surfaces

demonstrated the crystals on the Al/Pb–0.8%Ag anode are larger than on the Al/Pb–0.75%Ag–0.03%Co anode. After 24 h

of anodic polarization, SEM observations and XRD analysis showed that the MnO2–PbO2 layer on the Al/Pb–0.75%Ag–

0.03%Co anode surface is characterized by dendritic crystals, and the PbSO4–PbO2 layer under the MnO2–PbO2 layer is

characterized by uniform and chaotic orientation tetragonal symmetry crystallites of PbSO4. However, the MnO2–PbO2

layer on the Al/Pb–0.8%Ag anode surface is characterized by granular crystals, and the PbSO4–PbO2 layer under the

MnO2–PbO2 layer is characterized by well-organized orientation crystallites of PbSO4, which are concentrated in certain

zones.

KEY WORDS: Zinc electrowinning; Corrosion resistance; Electrocatalytic activity

1 Introduction

Corrosion resistance and electrocatalytic activity are two

problems encountered in a zinc electrowinning system. The

requirements and standards for the purity and grade of a

cathodic product are closely related to the creation of new

anodic materials with higher corrosion resistance and

electrocatalytic activity. Studies have reported that silver

[1–4], calcium and antimony [5, 6], stannum [6],

manganese [7], and cobalt [8–19], when used as alloying

element, increase the corrosion rate and decrease the

oxygen evolution reaction (OER) potential of the anode for

metal electrowinning. In fact, Pb–Ag alloy anodes are

generally used in the zinc electrowinning industry. How-

ever, the higher OER overpotential (approximately

860 mV) and the corrosion resistance of Pb–Ag anodes

remain as concerns in zinc electrowinning. A suitable

alternative to silver, cobalt has been found as a potential

additive in lead alloys. Cobalt doped has three routes:

Co3O4, Co, and Co2?.

The composites composed of Co3O4 particles and

graphite or Co3O4 particles and lead are used as anodes in

lithium ion batteries [8] because of the higher electrocat-

alytic activity. These composites are also used as anodes in

copper electrowinning [9] and zinc electrowinning [10]

because of the lower corrosion rate and oxygen evolution

potential. The presence of Co in Pb (in a concentration of

0.02–0.1 wt%) has been known to notably reduce the

Available online at http://link.springer.com/journal/40195

Y. Zhang � B. Chen (&) � Z. Guo

Faculty of Metallurgy and Energy Engineering, Kunming

University of Science and Technology, Kunming 650093, China

e-mail: 272601291@qq.com

Z. Guo

Kunming Hendera of Science and Technology Co. Ltd,

Kunming 650106, China

123

Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337

DOI 10.1007/s40195-014-0050-6

oxygen overpotential and corrosion rate of Pb [11]. Using

plasma spraying and detonation deposition of Pb–Co alloys

onto Pb, Forsen et al. [12] confirmed that Pb–Co anodes

had better electrochemical properties than Pb–Ag anodes

used in the industry. A new method of electrodeposition for

producing binary Pb–Co alloys was also determined [13–

16]. Used as anodes, Pb–Co composite coating on lead or

lead alloy matrix exhibits a corrosion resistance and elec-

trocatalytic activity higher than those of the Pb–Ag anode

[12–17]. Adding Co2? ion to copper sulfate [18] or zinc

sulfate electrolyte [19] also improves the corrosion resis-

tance and electrocatalytic activity of the anode.

WC, PANI, PbO2, and CeO2 particles electrodeposited

with Pb onto the aluminum matrix are used as anodes in

zinc electrowinning. The Al/Pb-PANI-WC [20], PANI/WC

[21], and Al/a-PbO2–CeO2–TiO2 anodes [22] are only

considered as anode materials in the laboratory. The PANI/

WC anode prepared via pressing is easily spit and peeled

off during electrolysis, thereby resulting in a shorter life-

time. a-PbO2–CeO2–TiO2 composite coating peels off

easily from the aluminum matrix because of the charac-

teristics of a-PbO2.

Based on the low cost and good conductivity of alumi-

num, Al/Pb–Ag and Al/Pb–Ag–Co composite anodes have

higher potential for study in zinc electrowinning. In this

paper, Al/Pb–0.8%Ag and Al/Pb–0.75%Ag–0.03%Co

anodes have been obtained through the electrodeposition of

lead methanesulfonate electrolyte onto aluminum plates.

Anode polarization curves, Tafe curves, and EIS have been

used in zinc sulfate electrolyte to measure the electro-

chemical properties of the two anodes. XRD analysis and

SEM observations showed the phase after 24 h of anode

polarization, as well as the microstructures before and after

24 h of anodic polarization, respectively.

2 Experimental

2.1 Process Method

The anode materials were prepared through electrodepos-

ition onto 3 cm 9 4 cm 9 3 cm aluminum plates, from a

standard lead methanesulfonate electrolyte containing

organic additives. The amount of organic additives, Co

(CH3SO3)2, and AgCH3SO3 used were 0–2 and 0.5–2 g/L,

respectively. Electrodeposition was conducted at pH values

range from 1.5 to 2, at a cathodic current density of 1

A/dm2, and with mechanical bubbling for 24 h at 40 �C.

2.2 Measurement and Analysis

An electrochemical workstation (CHI760C) with three

electrode systems was used to measure anode polarization

curves, Tafel curves, cyclic voltammetry curves, and EIS

characterization for Al/Pb–0.8%Ag and Al/Pb–0.75%Ag–

0.03%Co anodes in zinc sulfate electrolyte. The following

set-up was used: ZnSO4–H2SO4–MnSO4 system (Zn2?,

50 g/L; H2SO4,150 g/L; Mn2?, 3 g/L) and temperature of

35 �C. The counter electrode was a platinum plate and the

reference electrode was SCE with a potential of 0.24 V.

The two anodes were used as working electrodes. In

addition, SEM and XRD were used to determine the sur-

face microstructure and phase of the two anodes after 24 h

of anodic polarization, respectively.

3 Results and Discussion

3.1 Corrosion Resistance

Figure 1 shows the Tafel curves of Al/Pb–Ag and Al/Pb–

Ag–Co anodes in the zinc sulfate electrolyte. The corrosion

potential and corrosion current density are listed in

Table 1. Figure 1 illustrates that the Al/Pb–Ag–Co anode

has a higher potential than the Al/Pb–Ag anode at the same

current density from -0.55 to -0.45 V. As shown in

Table 1, the Al/Pb–Ag–Co anode has a higher corrosion

potential (-0.533 V) and a lower corrosion current density

(3.03 9 10-2 A/cm2), which imply higher corrosion

resistance.

Electrochemical corrosion rate can be defined as

v ¼ MJcorr

nF; ð1Þ

where v is the corrosion rate, Jcorr is the current density, M

is the metallic mole quality, n is the metallic valence, and F

is the Faraday constant. The corrosion rate v of the same

type of metal is proportional to the current density Jcorr.

Fig. 1 Tafel polarization curves of Al/Pb–0.75%Ag–0.03%Co and

Al/Pb–0.75%Ag anodes after anodic polarization for 24 h

332 Yongchun Zhang et al.: Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337

123

Thus, the Al/Pb–Ag–Co anode has a higher corrosion

resistance and a lower corrosion current density

(3.03 9 10-2 A/cm2) than the Al/Pb–Ag anode.

The corrosion tests were conducted on a model zinc

sulfate electrolyte under the following conditions: ZnSO4–

H2SO4–MnSO4 system, Zn2? (50 g/L), H2SO4 (150 g/L),

Mn2? (0.5 g/L), current density (500 A/m2), and temper-

ature (35 �C). Al/Pb–Ag–Co and Al/Pb–Ag anodes were

used as anodes (3 cm 9 4 cm 9 3 mm), and aluminum

plates were used as cathodes (3 cm 9 4 cm). The corrosion

rates of Al/Pb–Ag–Co and Al/Pb–Ag anodes are 0.441 and

0.873 mg/(cm2 h), respectively.

Corrosion rate can be defined as

K1 ¼ ðm0 � m1Þ=ðS0�tÞ;ð2Þ

where K1 is the corrosion rate (mg/(cm2 h)), m0 is the mass

of metal before corrosion, m1 is the mass of metal after

corrosion, S0 is the surface area of corroded metal, and t is

the corrosion time. The Al/Pb–Ag–Co anode has a smaller

corrosion rate (0.441 mg/(cm2 h)), which indicates a

higher corrosion resistance.

3.2 Tafel Curve and EIS Characterization

Figure 2 presents the anode polarization curves for the

Tafel analysis of Al/Pb–Ag and Al/Pb–Ag–Co anodes

conducted on zinc sulfate electrolyte. The parameters of

oxygen evolution dynamics are listed in Table 2.

The anodic polarization curve for Tafel analysis was

corrected by using the following formula [23]:

Ea ¼ Eappl � iRs; ð3Þ

where Ea is the real potential value of OER, Eappl is the

applied potential, i is the Faradaic current, and Rs is the

uncompensated electrolyte resistance. Figure 2 shows the

iR-corrected Tafel lines of Al/Pb–Ag and Al/Pb–Ag–Co

anodes on stable anodic layers after 24 h of anodic

polarization. All lines presented a double-slope behavior.

Based on the OER mechanism [23], the double-slope

values and potential intercepts of the two lines were

separately analyzed by using Origin software. The

overpotential g under specific current was calculated with

Tafel based on the following formula [23]:

g ¼ aþ b lg i0; ð4Þ

where a and b were constants, i0 was the electrode surface

current density, and g was the OER overpotential. a and b

were obtained through liner fitting of the plot g versus lgi0,

where a ¼ ai � E (the intercept value of ai obtained with

Origin). Comparing the Tafel and the Butler–Volmer

formulas in the high anodic polarization region, we can

express the exchange current density i0 as follows:

lg i0 ¼ � a

b; ð5Þ

where i0 is the exchange current density, i is the experiment

current, and E is the standard potential. Generally, the

values of i0 for OER are negligibly small and often con-

sidered meaningless in evaluating the electrocatalytic

activity of anode materials. As a result, the OER overpo-

tentials g are identified as one of the major criteria. The Al/

Pb–Ag–Co anode shows a lower OER overpotential than

the Al/Pb–Ag anode, which indicates that the anodic layer

is preferable to OER. In addition, Al/Pb–Ag–Co anode

presents a higher b1 and a lower b2, probably because of the

impeded mass and charge transfer in the micropores and its

microstructure that is prone to O2 evolution at the high

overpotential region [23].

EIS characterizations (Fig. 3a) of Al/Pb–Ag and Al/Pb–

Ag–Co anodes were conducted on zinc sulfate electrolyte

with an applied anodic potential set at a stable 1.80 V

versus SCE. The equivalent circuit (Fig. 3b) parameters of

the two anodes according to the EIS spectra are reported in

Table 3. Silva et al. [24], S. Palmas et al. [25], and Franco

et al. [26] stated that the introduction of the constant phase

elements (CPE) instead of capacitors (Cdl and Ca) for fit-

ting experimental data is a good approach to the

Fig. 2 Anode polarization curves of Al/Pb–0.8%Ag and Al/Pb–

0.75%Ag–0.03%Co anodes after anodic polarization for 24 h

Table 1 ucorr corrosion potential and Jcorr corrosion current density

of Al/Pb–0.8%Ag and Al/Pb–0.75%Ag–0.03%Co anodes

Anodes ucorr (V) Jcorr (A/cm2)

Al/Pb–Ag -0.545 7.21 9 10-2

Al/Pb–Ag–Co -0.533 3.03 9 10-2

Yongchun Zhang et al.: Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337 333

123

measurement of surface roughness, physical non-unifor-

mity, or non-uniform distribution of the surface reaction

site. CPE impedance (ZCPE) is defined by the following

formula:

ZCPE ¼1

QðjxÞn ; ð6Þ

where Q is the capacity parameter expressed in S cm-2sn,

and n accounts for the deviation from the ideal behavior

and has the value of 1 for perfect capacitors. Moreover, the

double-layer capacitance Cdl is coupled with the

uncompensated solution resistance Rs and the charge

transfer resistance Rt according to the following equation

[27]:

Qdl ¼ ðCdlÞn½ðRsÞ�1 þ ðRtÞ�1�ð1�nÞ: ð7Þ

Thus, using the model described by Eq. (7), Cdl is cal-

culated with the Qdl values obtained from the CNLS fit

[23]. Since Eq. (7) is specifically proposed for double-layer

capacitance, Qa parameters can be used to describe the

variation of adsorption pseudocapacitance Ca during elec-

trolysis, which actually reflects the variation of interme-

diate coverage on the anode surface. Such consideration is

based on the condition that n is close to 1. Q parameters

adequately describe the pseudocapacitance.

As shown in Table 3, the charge transfer resistance Rt

removes only a small part of the entire resistance, whereas

the film resistance Rf and adsorption resistance Ra domi-

nantly determine the final resistance values. In addition, the

Al/Pb–Ag–Co anode presents larger Qdl values than the Al/

Pb–Ag anode in the latter electrolysis, which may be

caused by the multilaminate (Fig. 4) and b-PbO2-rich (as

shown in Fig. 5) anodic layer.

3.3 Surface Microstructure and Phase

Figure 4 illustrates the SEM observations of the MnO2–

PbO2 and the PbSO4–PbO2 layers [28] under the MnO2–

PbO2 layer of Al/Pb–Ag and Al/Pb–Ag–Co anodes after

24 h of anodic polarization. Figure 4a, d indicates that the

oxide layers of Al/Pb–Ag and Al/Pb–Ag–Co anodes con-

sist of the MnO2–PbO2 and PbSO4–PbO2 layers, respec-

tively. The MnO2–PbO2 layer of the Al/Pb–Ag anode is

characterized by spherical particles with needle-like crys-

tals (Fig. 4c), and the PbSO4–PbO2 layer by uniform and

chaotic orientation tetragonal symmetry crystallites of

PbSO4 (Fig. 4b). The MnO2–PbO2 layer of the Al/Pb–Ag

anode is characterized by dendritic crystals (Fig. 4f), and

that of PbSO4–PbO2 by well-organized orientation crys-

tallites of PbSO4 concentrated in certain zones (Fig. 4d)

[29]. In addition, Fig. 5 shows the non-conducting phase of

PbSO4 and a-PbO2, as well as the conducting phase of b-

PbO2 on the PbSO4–PbO2 layer of the two anodes occur

after 24 h of anodic polarization. The conducting phase of

b-PbO2 on the PbSO4–PbO2 layer of the Al/Pb–Ag–Co

anode is greater than that of the Al/Pb–Ag anode.

Table 2 Parameters of oxygen evolution dynamics of Al/Pb–

0.8%Ag and Al/Pb–0.75%Ag–0.03%Co anodes

Anode g (mV) b1

(mV/dec)

b2

(mV/dec)

i0 (A/cm2)

Al/Pb–Ag 0.943 357 258 1.288 9 10-4

Al/Pb–Ag–Co 0.702 495 251 1.905 9 10-3

Fig. 3 a EIS characterization of Al/Pb–0.8%Ag and Al/Pb–0.75%Ag–0.03%Co anodes after anodic polarization for 24 h b the equivalent circuit

334 Yongchun Zhang et al.: Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337

123

Figure 6 shows the SEM observations on the fruit sur-

face of the Al/Pb–Ag (Fig. 6a–c) and Al/Pb–Ag–Co

(Fig. 6d, e) anodes. As indicated in Fig. 6d, the crystals of

lead on the fruit surface of the Al/Pb–Ag–Co anode are

dense with silver spherical crystallites, but the fruit surface

of the Al/Pb–Ag anode (Fig. 6a) is characterized by larger

lead crystals. This condition results in interstice and silver

on the fruit surface, which is not clearly related to the type

of inorganic additives of cobalt ions in the electrolyte. As

shown in Fig. 6b, e, the size of the lead crystals on the Al/

Pb–Ag–Co anode is smaller than that of crystals on the Al/

Pb–Ag anode. The silver on the fruit surface of the Al/Pb–

Ag–Co anode is bulbiform, and the silver crystals are

attached to the surface of the lead composite coating

(Fig. 6e). However, the silver on the fruit surface of the Al/

Pb–Ag anode has an elliptical shape and the silver crystals

are covered with lead (Fig. 6b). The different crystal sizes

of the lead, as well as the shape and existing way of silver,

are probably caused by the existence of the cobalt in the

Pb–Ag–Co composite coating.

Nucleation energy of the metallic ions on the electrode

surface can be calculated with the following formula:

A ¼ 32r2v2

n2F2g2A

; ð8Þ

where A is the nucleation energy of the crystal nucleus, gA

is the overpotential, r is the surface tension, and v is the

molar volume of the crystal. The relationship between

formation probability W and overpotential gA of the crystal

nucleus can be expressed as

W ¼ B exp � b

g2A

� �: ð9Þ

As shown in Fig. 6a, d, the lead crystals of the Al/Pb–Ag–

Co anode are smaller than the Al/Pb–Ag anode. As such, the

Al/Pb–Ag–Co anode has lower nucleation energy because of

Table 3 Equivalent circuit parameters of Al/Pb–0.8%Ag and Al/Pb–0.75%Ag–0.03%Co anodes after 24 h of anodic polarization according to

the EIS spectra

Anode Rs (X/cm2) Cf (F/cm2) Rf (X/cm2) Cdl (F/cm2) Rt (X/cm2) Qa (S/cm2sn) n Ra (X/cm2)

Al/Pb–Ag 0.89 0.04 0.55 4.35 0.08 5.10 0.86 3.76

Al/Pb–Ag–Co 0.95 0.03 0.51 18.45 0.10 14.30 0.87 3.53

Fig. 4 SEM images of Al/Pb–0.75%Ag–0.03%Co a–c and Al/Pb–0.8%Ag d–f anodes after anodic polarization for 24 h

Yongchun Zhang et al.: Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337 335

123

the smaller grain size that leads to higher corrosion resistance

[20]. A section of the Al/Pb–Ag anode is presented in

Fig. 6c, which demonstrates that the aluminum matrix of the

nickel transition layer, and in turn, of the lead–silver

composite coating, is combined tightly. Line scanning of

the Al/Pb–Ag anode section shows the same result (Fig. 6f).

The metallurgical process is apparent from the aluminum

matrix to the nickel transition layer and, in turn, to the lead–

silver composite coating. The results also prove that the

silver in the lead–silver composite coating has uniform

distribution.

4 Discussion

Based on the aforementioned considerations, the Al/Pb–

Ag–Co anode has a higher electrocatalytic activity and

corrosion resistance, which may be related to the cobalt

content of the Al/Pb–Ag–Co anode.

Ivanov et al. [29] reported that Co could promote the

process of O to O2 and of H to H2 on the surface of an

anode and a cathode, respectively. Mei et al. [30] and

Zhang et al. [31] determined that the main oxidation pro-

cesses involved in the lead anode were as follows:

Pb + SO24 � 2e = PbSO4 ESCE ¼ þ0:359 V

; ð10Þ

4OH� � 4e ¼ O2 + 2H2O ESCE ¼ þ1:473 V; ð11Þ

PbSO4 + 2H2O� 2e = PbO2 + H2SO4 + 2Hþ

ESCE ¼ þ1:924 V:ð12Þ

On a fresh anode surface, reaction (10) occurs first. The

anode surface is gradually covered with a non-conducting

layer of PbSO4. The current and potential on that part of

the anode surface are not yet covered with PbSO4. Reaction

(11) occurs instead of reaction (10) for a higher oxygen

Fig. 5 XRD of Al/Pb0.8%Ag a and Al/Pb–0.75%Ag–0.03%Co

b anodes after anodic polarization for 24 h

Fig. 6 SEM images on the fruit surface of Al/Pb–0.8%Ag a–c and Al/Pb–0.75%Ag–0.03%Co d, e anodes, line scanning of section of Al/Pb–

0.8%Ag anode f

336 Yongchun Zhang et al.: Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337

123

overpotential on the lead surface. PbO2 covers the surface,

which is well conducting, and the current density and the

anodic potential both decrease. The reaction of the O2

evolution (11) starts on the layer of PbO2 and sulfuric acid

renews in the electrolyte.

According to Alamdari et al. [19], the following con-

tinuous process occurs on the anode that contains Co:

4Co3þ + 2H2O ¼ 4Co2þ + 4Hþ + O2; ð13Þ

Co2þ � e ¼ Co3þ ESCE ¼ þ1:83 V: ð14Þ

This process occurs faster than reaction (15) and leads to

a lower oxygen potential, which is expressed as follows:

2H2O� 4e ¼ 4Hþ + O2; ð15Þ

Co� 2e ¼ Co2þ ESCE ¼ þ0:233 V: ð16Þ

Based on the aforementioned results, as well as

reactions (10), (13), (14), (15), and (16), the reactions of

Co on the surface of the Al/Pb–Ag–Co anode during zinc

electrowinning can be deduced. The catalytic processes of

Co on the surface of the Al/Pb–Ag–Co anode during zinc

electrowinning can be described by the following reaction:

Co! Co2þ ! Co3þ.

5 Conclusions

(1) Compared with the Al/Pb–0.8%Ag anode, the Al/Pb–

0.75%Ag–0.03%Co anode has a higher electrocata-

lytic activity, a lower OER overpotential (0.81 V), and

a double-layer capacitance. The Al/Pb–0.75%Ag–

0.03%Co anode also has a higher corrosion resistance

for a higher corrosion potential (-0.533 V), lower

corrosion current density (3.03 9 10-2 A/cm2), and a

corrosion rate of 0.441 mg/(cm2 h). Such results may

be attributed to the preparation of the Al/Pb–0.75%Ag–

0.03%Co anode and the reaction of Co during zinc

electrowinning.

(2) In addition, the Al/Pb–0.75%Ag–0.03%Co anode has

MnO2–PbO2 and PbSO4–PbO2 layers with the differ-

ent microstructures from that of the Al/Pb–0.8%Ag

anode, which may attributed to the cobalt in the Pb–

Ag–Co composite coating.

(3) The catalytic processes of Co on the surface of the Al/

Pb–Ag–Co anode during zinc electrowinning probably

occur via the following reaction:Co! Co2þ ! Co3þ.

Acknowledgments This work was financially supported by the

National Natural Science Foundation of China (No. 51004056),

Kunming Hendera of Science and Technology Co. Ltd., and the

Analysis and Measurement Foundation of Kunming University of

Science and Technology.

References

[1] P. Yu, T.J. O’Keefe, J. Electrochem. Soc. 149, 558 (2002)

[2] C. Rerolle, R. Wiart, J. Electroch. Acta 40, 939 (1995)

[3] A. Felder, R.D. Prengaman, J. Miner. Metals Mater. Soc. 5, 28

(2006)

[4] Y.Q. Lai, L.X. Jiang, J. Li, S.P. Zhong, X.J. Lv, H.J. Peng, Y.X.

Liu, Hydrometallurgy 102, 73 (2010)

[5] C. Lupi, D. Pilone, Hydrometallurgy 44, 347 (1997)

[6] A. Hrussanova, L. Mirkova, T. Dobrev, Hydrometallurgy 72,

215 (2004)

[7] H. Liu, Y.Y. Wang, L.Y. Chai, H.J. Xiao, F. Pei, Y.D. Shu,

Trans. Nonferr. Metal Soc. China 21, 1665 (2001)

[8] H.J. Guo, X.Q. Li, X.H. Li, Z.X. Wang, W.J. Peng, Q.M. Sun, J.

Xie, J. Cent. South Univ. Technol. 17, 4983 (2010)

[9] A. Hrussanova, L. Mirkova, T. Dobrev, Hydrometallurgy 7, 205

(2004)

[10] S. Cattarin, P. Guerriero, M. Musiani, Electrochim. Acta 46,

4229 (2001)

[11] Y. Stefanov, Ts Dobrev, Trans. Inst. Metal Finish. 83, 296

(2005)

[12] O. Forsen, J. Kukkonen, J. Aromaa, S. Ylasaary, in Proceeding

to the European seminar Improved Technologies for the

Rational Use of Energy in the Non-ferrous Industry in Europe,

Milan, Italy, Proc., November 18–20, 1992

[13] S. Rashkov, T. Dobrev, Z. Noncheva, Y. Stefanov, B. Rashkova,

M. Petrova, Hydrometallurgy 52, 223 (1999)

[14] I. Ivanov, Y. Stefanov, Z. Noncheva, M. Petrova, T. Dobrev, L.

Mirkova, R. Vermeersch, J.P. Demaerel, Hydrometallurgy 57,

125 (2000)

[15] S. Luby, E. Majkova, M. Jergel, R. Senderak, G. D’Anna, A.

Leggieri, M.M. Luches, Thin Solid Films 359, 141 (2000)

[16] Y. Stehanov, T. Dobrev, Trans. Inst. Metal Finish. 83, 296

(2000)

[17] C. Cacahet, C.L. Rerolle, R. Wiart, J. Appl. Electrochem. 29,

811 (1999)

[18] H. Huang, J.Y. Zhou, Z.C. Guo, Trans. Nonferr. Met. Soc. China

20, 55 (2010)

[19] E.K. Alamdari, D. Darvishi, M.S. Khoshkhoo, F.A. Javid, S.P.H.

Marashi, Hydrometallurgy 119, 77 (2012)

[20] R.D. Xu, L.P. Huang, J.F. Zhou, P. Zhai, Y.Y. Guan, Y. Kong,

Hydrometallurgy 125, 8 (2012)

[21] H. Huang, Z.C. Guo, J.K. Li, Chin. J. Process Eng. 10, 1020

(2010). (in Chinese)

[22] B.M. Chen, Z.C. Guo, H. Huang, Adv. Mater. Res. 306, 787

(2011)

[23] Y.Q. Lai, Y. Li, L.X. Jiang, W. Xu, X.J. Lv, J. Lie, Y.X. Liu, J.

Electroanal. Chem. 671, 16 (2012)

[24] L.M. Silva, J.F.C. Boodts, L.A.D. Faria, Electrochim. Acta 46,

1369 (2011)

[25] S. Palmas, A.M. Polcaro, F. Ferrara, J.R. Ruiz, F. Delogu, C.

Bonatto-Mine, G. Mulas, J. Appl. Electrochem. 38, 907 (2008)

[26] D.V. Franco, L.M.D. Silva, W.F. Jardim, F.C.J. Boodts, J.

Brazil, Chem. Soc. 17, 746 (2006)

[27] G.J. Brug, A.L.G. Vanden-Eeden, M. Sluyters-Rehbach, J.H.

Sluyters, J. Electroanal. Chem. 176, 275 (1984)

[28] T.T. Chen, J.E. Dutrizac, J. Electrochem. Soc. 149, A5589 (2002)

[29] I. Ivanov, Y. Stefanov, Z. Noncheva, M. Petrova, T. Dobrev, L.

Mirkova, R. Vermeersch, J.P. Demaerel, Hydrometallurgy 57,

109 (2000)

[30] G.G. Mei, D.R. Wang, J.Y. Zhou, Hydrometallurgy of zinc

(Central South University Publishers, Changsha, 2001),

pp. 342–343. in Chinese

[31] W. Zhang, G. Houlachi, Hydrometallurgy 104, 129 (2010)

Yongchun Zhang et al.: Acta Metall. Sin. (Engl. Lett.), 2014, 27(2), 331–337 337

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