Minimisation and recycling of spent acid wastes from galvanizing plants

Stocks, C.; Wood, Joseph; Guy, S.

doi:10.1016/j.resconrec.2004.11.005

Cited by 63 publications

(24 citation statements)

References 4 publications

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“…These values were determined by AAS following the operating conditions presented in Section 2.3 These measured values are similar to those reported in the literature [1,2,7]. This sample was diluted to 1:50, in order to perform the voltammetric and electrolysis experiments.…”

Section: 1-voltammetric Studymentioning

confidence: 60%

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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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Section: 1-voltammetric Studymentioning

confidence: 60%

“…Therefore, spent pickling baths contains hydrochloric acid, ZnCl 2 and FeCl 2 as principal compounds. The composition of the baths will change greatly depending on how long it has been used for pickling [2] but they mainly contain 80-150 g/l FeCl 2 , 5-150 g/l ZnCl 2 and 10-80 g/l HCl [1].…”

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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“…Acid waste of the pickling acid released from galvanization plants in UK contains 192,000 mg l -1 of zinc. The acid waste is transported to special treatment facility, where all the valuable metals are being lost (Stocks et al 2005). Usually, the industries involved in galvanization, other similar type of industries and acid mine drainage operations, recycle their effluents to recover the valuable metals.…”

Section: Zinc Toxicity Remediation Technologies and Characterizationmentioning

confidence: 99%

Biosorption of zinc ion: a deep comprehension

Mishra

2014

Appl Water Sci

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Massive industrialization and urbanization of civilization during the last few decades have made a thrust in heavy metal pollution in various water bodies. In past, various kinds of conventional metal ion remediation technologies, such as cementation, osmosis, reverse osmosis, ultrafiltration, etc., have been practised. However, most of these technologies are quite expensive, and lead to the generation of secondary chemical sludge. However, biosorption of heavy metal ions is significantly inexpensive and an eco-friendly technology. Among the series of heavy metals, zinc has gained the significant interest due to its toxicity and easy availability in water bodies. Biosorption of zinc in liquid phase by living, nonliving, conventional and non-conventional biosorbents has been practised extensively in the past. This literature review focuses on the recent trends practised in the field of biosorption of zinc from liquid phase. The present work provides deep insight into various aspects of biosorption of zinc by different mechanisms of biosorption, bioaccumulation, isotherm, kinetic and mechanistic modeling. An exhaustive comparison among different sorts of biomasses has also been given in the present work to enlist all the milestones of biosorption.

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“…Finally, if both kinds of pieces are treated, a mixture effluent will be obtained, whose typical composition is 80-120 g/l of Fe, 20-60 g/l of Zn and 30-50 g/l of HCl [2]. The production of the spent pickling bath gives rise to an environmental problem that has to be solved due to the hazardous nature of the effluents [3]. However, due to the complexity of the hydrochloric acid effluents, which are usually found as chloro-complexes, the development of an adequate treatment for this effluent is very …”

Section: -Introductionmentioning

confidence: 99%

Treatment of spent pickling baths coming from hot dip galvanizing by means of an electrochemical membrane reactor

2014

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The performance of a one (OCR) and a two-compartment electrochemical reactor in the presence of a cation-exchange membrane (CEM) for the zinc recovery present in the spent pickling baths is analyzed in this paper under galvanostatic control. 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 applied current, the dilution factor of the baths and the presence or absence of initial cathodic zinc is also studied.For the 1:50 diluted spent bath, OCR experiments initially present higher values of the figures of merit than those obtained in the presence of the CEM since zinc is close to the cathode from the first electrolysis instants. However, at long electrolysis times, OCR presents zinc redissolution for all the current values tested due to the chlorine and iron presence close to the zinc deposits. In addition, the iron codeposition phenomenon is also observed in the OCR experiments when pH values are close to 2. On the other hand, CEM experiments become very similar to the OCR experiments at long time values since the CEM under these experimental conditions prevents zinc redissolution phenomenon and also iron codeposition. 2When the 1:50 diluted bath is concentred to 1:10, OCR experiments present the same tendency as that observed for the 1:50 dilution factor but the effect of zinc redissolution is increased due to the greater amount of chlorine generated in the anode. Under these experimental conditions, iron deposition has also been observed in the presence of the cation-exchange membrane as the rate of zinc deposition is greater than that of zinc transport through the membrane, and the zinc/iron ratio in the cathodic compartment is not high enough to prevent iron codeposition. In both cases, the pH values when iron codeposits with zinc is close to 2 and the zinc/iron ratio is below 0.6. The presence of initial zinc in the cathodic compartment of the electrochemical reactor enhances the reactor performance since allows the zinc-iron separation in one single step and avoids the zinc redissolution phenomenon. 1-IntroductionThe pickling step, previous to the galvanized process, consists of attacking the surface of the pieces with HCl in order to clean them from rust and impurities. This process generates a succession of effluents containing, among other substances, high concentrations of ZnCl 2 , FeCl 2 and HCl [1]. The composition of these baths depends on the kind of the pieces cleaned. If the pieces pickled are new ones, an iron rich effluent will be obtained, whose typical composition is 100-160 g/l of Fe, 5-10 g/l of Zn and 30-50 g/l of HCl; but if these pieces have previously been galvanized, the effluent would be rich in zinc and its typical composition would be 10-20 g/l of Fe, 80-230 g/l of Zn and 10-30 g/l of HCl. Finally, if both kinds of pieces are treated, a mixture effluent will be obtained, whose typical composition is 80-120 g/l of Fe, 20-60 g/l of Zn and 30-50 g/l of HCl [2]. The production of the spent ...

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Minimisation and recycling of spent acid wastes from galvanizing plants

Cited by 63 publications

References 4 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

Biosorption of zinc ion: a deep comprehension

Treatment of spent pickling baths coming from hot dip galvanizing by means of an electrochemical membrane reactor

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