An investigation of the spouted bed electrode cell for the electrowinning of metal from dilute solutions - 42 2 g - 2 8 Jj pA =

~ The depletion process of copper ions from dilute solutions has been used as a model system to investigate the spouted bed cell with a three-dimensional electrode of conducting particles. Experiments under potentiostatic and galvanostatic conditions have been carried out. Results obtained indicate that the spouted bed cell has several favourable characteristics for application in metal recovery. The potentiostatic mode of operation appears to be superior to the galvanostatic mode for electrowinning, 1. Introduction Three-dimensional electrode cells have been investigated extensively over the past two decades and have been shown to be suited to applications in different areas such as electrowinning. effluent treatment and electroorganic synthesis. The extremely high specific surface area of these 'new generation' cells makes them attractive systems for numerous electrochemical processes which can only be successfully carried out with low current densities. The early research in three-dimensional electrodes was focused on the fixed and fluidized bed, especially on the latter. The main purpose of these investigations was application of the cell for the winning of heavy metals from very dilute solutions [ 1-31. Despite early optimism the fluidized bed electrode (FBE) cell has manifested many limitations in later investigations such as: poor conductivity of the dispersed phase at higher bed expansion , deposition of metal on the feeder electrode and diaphragm, channelling through the bed in scaled up cells, bipolar characteristics with large interelectrode distances, relatively short lifetime of the diaphragm etc. [ I , 4, 51. Some of these shortcomings have seriously limited the viability of the FBE cell f G i metal iecki-mation. The disadvantages prompted the appearance of some new types of cell, derived from the FBE cell, such as the inclined FBE cell [6], the moving bed cell [7], the vortex bed cell [8] and the spouted bed cell 14, 5, 91. The spouted bed electrode (SBE) cell attracted greater attention than the other types of cells, and there is a greater wealth of published data. Thus, Coeuret el al. [4] have measured the potential distribution across the inclined half column SBE cell. Scott [5] has also investigated the half column SBE cell, also making a comparison between different kinds of three-dimensional cells. Hadfismailovik et ai. [9] have investigated a cylindrical diaphragmless SBE cell with a counter electrode outside the bed with particular. I Based on Scott's results [5] it may be concluded that the SBE cell is a promising electrochemical reactor …