Zadra cell

Zadra cell — Electrolytic cell employed in -> electrowinning of gold. The design is based on placing into a perforated cylindrical polymer container steel wool as - cathode, a feeder tube, and a -> current distributor. The anode is a stainless steel mesh outside the container. Gold-rich solution is fed at low feed rate through the feeder at the bottom of the steel wool-filled compartment, gold is reductively extracted, and the extracted solution passes the polymer container. 

Porous electrodes have the same advantages as particle bed reactors, but they have the difficulty of becoming plugged as the metal deposit builds up. Sometimes this is not important if the value of the deposited metal is high and the electrode may be sacrificed. An example of such a system is the Zadra cell used in gold electrowinning, where the cathode is a steel mat that can be melted away when gold is recovered. 

FIf. 47 Gold electrowioning cdls. (a) The traditional Zadra cell design, (b) A modified Zadra cell, the improved mass -transfer cell. (Alter US Bureau of Mines.)... 

The Zadra cell, however, suffers from several drawbacks ... 

While many types of cell design are currently in use, the Zadra type of cell (Fig. 4.7(a)) has been favoured by industry since its inception in 1952 The design... 

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