Chemelec cell

Chemelec cell BEWT (Water Engineers) Ltd Vertical mesh (or plate) in an electrolyte with fluidized glass beads Discontinuous by manual scraping or reuse as anodes in plating No V ... 

Chemelec cell — An electrolytic cell with electrodes (both anode and cathode) made from expanded metal or simple metal plates. The cell is filled with inert particles, which are floated when the electrolyte solution enters the cell from the bottom. This causes effectively turbulence with increased - mass transport. This cell is employed in wastewater treatment especially from galvanic operations. 

Cells with relatively small electrode area but improved mass transport to increase km by setting the electrodes in motion or by applying turbulence promoters. Examples are the pump cell [55, 56], the Chemelec cell [57], the ECO cell [58-60], the beat-rod cell [61, 62], and cells with vibrating electrodes or electrolytes [63]. 

The Chemelec cell, Fig. 4(b), uses a fluidized bed of glass spheres as turbulence promoters to improve the mass transport to the electrodes consisting of a series of closely spaced gauze or expanded metal sheet. The residence time and the degree of conversion per pass are relatively low because the flow rate has to exceed the fluidization velocity of the bed. This cell is therefore suitable for pretreatment or recycling operations and is commonly used in the electroplating industry for maintaining a moderate metal ion concentration in a recirculated wash-water tank. 

Chemelec cell with fluidized-bed glass beads within electrodes. The cell performance is achieved mainly by electrolyte movement. The cathode product is removed by scraping or used as anodes. 

Chemelec cell (inert fluidised bed) Swiss Roll cell... 

Figure 11.6 (a) Chemelec plant sited above a plating line, (h) Replacement of the electrodes in a Chemelec cell. Photographs supplied by the Electricity Research Council, Capenhurst. 

Two-dimensional electrodes. Two-dimensional electrodes appropriate for metal recycling are typically based on the tank electrolyser to enable ready removal of metal plated electrodes. The simplest cells are the vertical, plate or mesh, electrode in tank units where turbulence is provided by using either inert fluidised beds [8] (Chemelec Cell, BEWT Water Engineers Ltd.) or air agitation (Reconwin cell), in conjunction with electrolyte pumping (see Figure 11.3). 

Fig.3 Chemelec Cell, 1- expanded steel or titanium mesh cathode, 2-DSA Ti/Ru02 coated anode, 3- process steam inlet. A and B expanded view of cathode showing, A expanded mesh and B -inert ballotini used for fluidised mass-transfer enhancement...

The Chemelec cell[16] using mesh electrodes in a nonconducting fluidized bed compartment, with continuously upwards flowing electrolyte. 

A commercially available cell " uses this type of particulate turbulence promoter in the form of a fluidized bed of electrochemically inert particles, typically glass spheres. This Chemelec cell is aimed at the secondary recovery of metals and their removal from effluents. Little reliable information is available on mass transfer to spheres in a fluidized bed. Nassif, using a limited current technique, investigated mass transfer to the particles of a fluidized bed as well as to the wall enclosing them. For the latter he derived ... 

Chemelec cell (inert fluidized bed) Swiss-roll cell... 

Another practical approach is to promote electrolyte turbulence via the use of an expanded-mesh electrode in a solution containing fluidized inert particles (typically 1 mm glass ballotini). This is the principle of the Chemelec cell (Fig. 7.4) which has been widely applied to metal finishing, photographic silver-recovery and precious metal reclamation processes. 

Fig. 7.4 The Chemelec cell installed as part of a batch recycle loop on a static electroplating rinse tank. (Courtesy The Electricity Council.)...

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