Current efficiency studies of the zinc electrowinning process on aluminum rotating cylinder electrode (RCE) in sulfuric acid medium: Influence of different additives

Recéndiz, Alejandro; González, Ignacio; Nava, José L.

doi:10.1016/j.electacta.2007.04.112

Cited by 49 publications

(13 citation statements)

References 22 publications

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“…This peak is a mixture of A1 and A2 peaks, which suggests the zinc deposition over the platinum electrode for the Fe/Zn mixture. The porosity observed by SEM in the majority of the deposit obtained in the conditions presented in curve c), obtained after 2h electrolysis at -1.5V, indicates that a large amount of hydrogen gas is formed as predicted by the cyclic voltammograms experiments [13]. On the other hand, the composition of this sample reveals a zinc percentage of 99%.…”

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confidence: 94%

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Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation

Carrillo-Abad

García-Gabaldón

Ortega

et al. 2011

Separation and Purification Technology

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ElsevierCarrillo Abad, J.; García Gabaldón, M.; Ortega Navarro, EM.; Pérez-Herranz, V. (2011). Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation. Separation and Purification Technology. 81 (2) Keywords: electrochemical deposition, iron, hydrogen evolution reaction, pickling solutions, zinc electrodeposition AbstractAn electrochemical reactor was developed to recover zinc from the spent pickling solutions coming from the hot dip galvanizing industry. These solutions mainly contain ZnCl 2 and FeCl 2 in aqueous HCl media. The effect of the applied potential on the figures of merit (fractional conversion, current efficiency, space-time yield and specific energy consumption) of the electrochemical reactor was analysed. Voltammetric experiments were performed previously in order to select the optimum conditions to be applied in the electrolysis experiments. From the i-V curves it was inferred that bulk zinc deposition started from potential values more cathodic than -0.99V. The hydrogen evolution reaction (HER) appeared from -0.45V and masked the zinc cathodic peak C1, 2 related to bulk zinc deposition, at high HCl concentrations. The presence of HCl inhibited iron deposition in synthetic samples. The additives present in the real baths, which diminish the massive hydrogen generation, allowed the observation of peak C1.The potential values to be applied in the electrolysis experiments were chosen from the voltammetric experiments and ranged between -1V and -1.75V. In the absence of iron in solution, as the electrode potential was shifted towards more negative values, the space-time yield of zinc and its fractional conversion increased because of the increase in the electrode roughness and the hydrogen turbulence-promoting action.Simultaneously, the specific energy consumption decreased initially due to the increase in the zinc conversion rate but decreased for the most cathodic potential value due to HER. The presence of iron in synthetic solutions led to a decrease in current efficiency associated with the reverse redox Fe 2+ /Fe 3+ system and to the enhancement of the HER, which also induced increments in the local pH and the subsequent zinc redissolution for the most cathodic potential values. On the contrary, the additives present in the real spent pickling baths avoided the adverse effects of iron, and zinc electrodeposition was possible even at high cathodic potential values. In fact, a potential value of -1.75V was selected as the optimum since the conversion, the current efficiency and the space time yield obtained in the real baths were relatively high.3

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confidence: 94%

“…On the other hand, the electrolytic recovery of zinc is one of the oldest industrial processes, whose importance lies in the great worldwide demand for this metal that currently reaches an overall production of 9 million tonnes per year [5]. In fact, 80% of world zinc production is obtained by electrowinning [4].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation

Carrillo-Abad

García-Gabaldón

Ortega

et al. 2011

Separation and Purification Technology

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“…Recéndiz et al, (15) have studied the influence of different additives [CTABr, SLS, and AG] on the current efficiency of the zinc EW process on aluminium rotating cylinder electrodes (RCE) in sulfuric acid medium. CTABr favored zinc reduction and inhibited proton reduction, whereas SLS catalyzed proton reduction on aluminium substrates leading to deposit porosity.…”

Section: Introductionmentioning

confidence: 99%

An Investigation on the Effects of Organic Additives on Zinc Electrowinning from Industrial Electrolyte

et al. 2010

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The influence of Saponin, Licorice, Tennafroth 250, and Dowfroth 250 at different concentration levels (0, 5, 10, and 15 ppm) were investigated during zinc electrowinning from industrially supplied spent electrolyte. Acid mist suppression efficiency, polarization behavior, current efficiency and energy consumption were investigated for a current density of 500 A.m -2 . Surface tension measurements were used to find a correlation between the concentration of the different additives and the acid mist suppression efficiencies. Morphological and crystallographic orientation studies indicated dense and well defined crystalline grains with homogeneous distribution mostly at the 5 ppm level of suppressant. Electrowinning in the presence of Saponin and Tennafroth was found to have high current efficiencies of 90% each with low energy consumptions of 2641 and 2675 kWh/t, respectively and the deposited crystals were found to be oriented preferably in the [101]

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“…In addition, the decrease of natural reserves of non-ferrous metals and the requirement of environmental protection make zinc electrowinning from spent pickling solutions an interesting alternative [4,5]. Moreover, the electrolytic recovery of zinc present in the spent pickling baths is a suitable technique because zinc electrowinning has been practiced for many years [6]. In fact, 80% of world zinc production is obtained by electrowinning [1].…”

Section: -Introductionmentioning

confidence: 99%

Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation

Carrillo-Abad

García-Gabaldón

Ortega

et al. 2012

Separation and Purification Technology

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ElsevierCarrillo Abad, J.; García Gabaldón, M.; Ortega Navarro, EM.; Pérez-Herranz, V. (2012). Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation. Separation and Purification Technology. 98:366-374. doi:10.1016/j.seppur.2012.08.006. Keywords: electrochemical deposition, chlorine, iron, redissolution, pickling solutions, zinc electrodeposition 1 RECOVERY OF ZINC FROM SPENT PICKLING SOLUTIONS USING AN ELECTROCHEMICAL REACTOR IN PRESENCE AND ABSENCE OF AN ANION-EXCHANGE AbstractThe performance of a one and two-compartment electrochemical reactor under galvanostatic control for zinc recovery present in the spent pickling solutions is studied in this paper. These solutions, which mainly contain ZnCl 2 and FeCl 2 in aqueous HCl media, come from the hot dip galvanizing industry. The effect of the anion-exchange membrane (AEM) on the figures of merit of the electrochemical reactor is analyzed.In the absence of iron in solution, as the current value was shifted towards more negative values, the zinc fractional conversion increased because of the increase in the 2 zinc reduction rate. However, the increase in current values made current efficiency decrease due to the hydrogen-reduction side reaction, which caused an increment in the specific energy consumption. The presence of iron in synthetic solutions led to a decrease in current efficiency associated with the reverse redox Fe 2+ /Fe 3+ system and to the enhancement of the HER, which also induced increments in the local pH and the subsequent zinc redissolution. These adverse effects related to the presence of iron could be minimized by the interposition of an AEM. In this case, the zinc redissolution was eliminated which enabled zinc conversion values close to 100% together with higher current efficiencies as the consumption of current by the system Fe 2+ /Fe 3+ was diminished.3 1-IntroductionHot dip galvanizing processes offer a simple and effective way for corrosion protection of steel parts. This protection is based on covering the steel with a thin layer of metallic zinc that protects steel from corrosion by two ways: surface coating and sacrificial anode as zinc is lees noble than iron. This process consists of the following steps: HCl. This gives rise to an environmental problem that has to be solved due to the hazardous nature of the effluents [2,3]. In addition, the decrease of natural reserves of non-ferrous metals and the requirement of environmental protection make zinc electrowinning from spent pickling solutions an interesting alternative [4,5]. Moreover, the electrolytic recovery of zinc present in the spent pickling baths is a suitable technique because zinc electrowinning has been practiced for many years [6]. In fact, 80% of world zinc production is obtained by electrowinning [1].In our previous paper [7], the potentiostatic recovery of zinc present in the spent pickling bath using an electrochemical reactor was studied. The major interfering re...

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Current efficiency studies of the zinc electrowinning process on aluminum rotating cylinder electrode (RCE) in sulfuric acid medium: Influence of different additives

Cited by 49 publications

References 22 publications

Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation

Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation

An Investigation on the Effects of Organic Additives on Zinc Electrowinning from Industrial Electrolyte

Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation

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