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Journal of Applied Electrochemistry

, Volume 1, Issue 2, pp 103–112 | Cite as

Fluidized bed electrodes Part IV. Electrodeposition of copper in a fluidized bed of copper-coated spheres

  • M. Fleischmann
  • J. W. Oldfield
  • L. Tennakoon
Papers

Abstract

The effective resistivity of the discontinuous metal phase in a fluidized bed copper electrode is derived from measurements of the potential distribution in the solution. The values are similar to those which have been previously observed for a fluidized bed of silver-coated particles and are compared with a theoretical expression based on a model of charge sharing during single particle elastic collisions. It is shown that the metal resistivity follows the predicted dependence on bed expansion and solution resistivity; the constant of proportionality is, however, different and this is attributed to a stagnation zone close to the feeder electrode. Such a stagnant zone is also indicated by comparison of the experimental and theoretically predicted distribution of potential in the metal phase.

The diffusion controlled removal of copper from 10−4 M copper sulphate is also shown to follow the theoretically predicted behaviour; the mass transfer coefficient indicates a high degree of turbulence within the bed. It is shown that scale-up factors of the order of 300 can be achieved in the processing of such dilute solutions. In view of the relatively high resistivity of the metal phase it is suggested that practical systems would arrange for a current and fluid flow to be at right angles to each other.

Keywords

Mass Transfer Coefficient Metal Phase Copper Electrode Elastic Collision Theoretical Expression 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Glossary

A

surface area per unit volume of electrode (cm−1)

C

double layer capacity (Farads cm−2)

c0

concentration (moles cm−3)

D

diffusion coefficient (cm2 s−1)

F

the Faraday (coulombs mole−1)

I

total current (A cm−2)

i

local current density (A cm−2)

io

exchange current density (A cm−2)

Km

mass transfer coefficient (cm s−1)

n

equivalents per mole

R

gas constant (volt coulomb deg−1 mole−1)

r

particle radius (cm)

T

absolute temperature

u

superficial solution velocity (cm s−1)

V

voidage

vp

mean particle velocity (cm s−1)

x

distance from feeder in direction of current flow (cm)

α

electrochemical transfer coefficient for an anodic reaction

γ

Young's modulus (dynes cm−2)

δ

Solution-metal diffusion layer thickness (cm)

ε

electrode length normalized w.r.t. the static bed length

η

local overpotential (volts)

λ

characteristic length (cm)

π

solution-particle density difference (g cm−3)

πm

effective specific resistivity of the discontinuous metal phase (ω cm)

πs

effective specific resistivity of the solution phase (ω cm)

φm

metal potential (volts)

φs

solution potential (volts)

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Copyright information

© Chapman and Hall Ltd 1971

Authors and Affiliations

  • M. Fleischmann
    • 1
  • J. W. Oldfield
    • 1
  • L. Tennakoon
    • 1
  1. 1.Department of ChemistryThe UniversitySouthamptonUK

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