Electrolytic Refining and Winning of Metals

Ettel, V.; Tilak, B. V.

doi:10.1007/978-1-4684-3785-0_6

Cited by 17 publications

(2 citation statements)

References 9 publications

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“…This is not unlike the usual electrowinning industrial practice. The results of Krause and Vogt show that for small flow rates encountered during acid zinc electrowinning (approximately 1.33 cm/s) (52) and high temperatures (353 K), more than 90% of the dissolved hydrogen reaching the solution bulk is evolved as bubbles at current densities higher than I-0.0011A/cm e. This is explained by the fact that the solubility is low and only a small quantity of dissolved gas is carried out by the electrolyte flow. This was confirmed experimentally by the results of MQller et al (41).…”

Section: Discussionmentioning

confidence: 99%

Ionic Mass Transfer of Zinc in Alkaline Solutions with Simultaneous Hydrogen Evolution

St‐Pierre

Piron

1992

J. Electrochem. Soc.

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Sherwood numbers were determined for mass transfer of zinc in alkaline solutions with coevolution of hydrogen (0.15-0.9 mmol/cm 3 ZnO + 8.4 mmol/cm 3 KOH, 300 K). The separation between the zinc and the hydrogen current was performed using polarization curves. The separation between Sherwood numbers due to natural and bubble convection was obtained by an additive law since hydrogen evolution took place only at current densities higher than the zinc limiting current density. It is shown that the contribution to mass transfer by bubbles, relative to natural convection, increases with both zinc concentration and hydrogen current density. Under industrial conditions of high zinc concentration (0.9 mmol/cm 3 ZnO) and high current densities (-0.24 A/cm2), the effect of the hydrogen bubbles is predominant even if the hydrogen current efficiency is low (3.3%), the Sherwood numbers being, respectively, 424 and 115. The data obtained in this work and others give support to the dimensionless correlation StSc 0.~ = 0.035(FrRe) -0.2~

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Section: Discussionmentioning

confidence: 99%

Ionic Mass Transfer of Zinc in Alkaline Solutions with Simultaneous Hydrogen Evolution

St‐Pierre

Piron

1992

J. Electrochem. Soc.

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“…Only in the past 20 years, considerable attention has been paid to two main industrial application of cementation. The first involves the recovery of metals from leach solutions (Biswas and Davenport, 1979) and the second is concerned with the purification of electrolyte solutions to remove metals which are more electropositive than the metal to be deposited, such as Cu, Co, Ni, Cd and as from ZnSO 4 electrolyte (Ettel, 1981). It has been reported that electrochemistry of the reaction at room temperature is diffusion controlled (Antropov and Donchenko, 1972; Biswas and Reid, 1973; El Batouti, 1999; El Batouti, 2003a; El Batouti, 2003b; Power and Ritchie, 1981 and Zaghloul et al , 1996).…”

Section: Introductionmentioning

confidence: 99%

Removal of Pb⁺⁺ in presence of surfactants

El‐Batouti

2007

Anti-Corrosion Methods and Materials

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PurposeThe object of the present work is to study the kinetics of removal of Pb++ on zinc rods in the presence and absence of three surface active substances (SAS) at different concentrations of SAS and different temperatures.Design/methodology/approachThe paper uses a range of recently published (1973‐2003) works, which aim to provide practical and theoretical information about lead, which is a very toxic metal.FindingsLead tends to accumulate a sediment, from which it can be released by various processes of remobilization and in many cases it enters the food chain and is concentrated in fish and other edible organisms. The reaction can be considered as taking place via six steps.Research limitations/implicationsThe work is a list of recent papers which have been published in different European journals and magazines.Practical implicationsThe determination of change of Pb++ concentrations was carried out using a Perkin‐Elmer atomic absorption Spectrophotometer.Originality/valueThe rate of PbII/Zn cementation reaction in the presence of surfactants as non‐ionic (Triton‐X‐100), anionic (SDS) and cationic (CTAB) decreased compared with the blank solution (lead nitrate solution). The order of decreasing rate was as follows: Triton‐X‐100 > CTAB > SDS. The rate of cementation was increased by temperature and the value of ΔE* ranged between 27 and 33 kJmol−1, which indicated that the reaction is a diffusion‐controlled process. The presence of two different SAS in the solution is more effective than the presence of one only.

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